This is a resend of [1] with a few modification due to drm core function
changes and use regmap abstraction.
The gpio mux driver is required for MT8173 board layout:
/-- anx7688
-- MT8173 HDMI bridge -- GPIO mux
\-- native HDMI
[1] https://lore.kernel.org/lkml/[email protected]/
Nicolas Boichat (4):
dt-bindings: drm/bridge: analogix-anx7688: Add ANX7688 transmitter
binding
drm: bridge: anx7688: Add anx7688 bridge driver support.
dt-bindings: drm/bridge: Add GPIO display mux binding
drm: bridge: Generic GPIO mux driver
.../bindings/display/bridge/anx7688.yaml | 60 ++++
.../bindings/display/bridge/gpio-mux.yaml | 89 +++++
drivers/gpu/drm/bridge/Kconfig | 19 ++
drivers/gpu/drm/bridge/Makefile | 2 +
drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++
drivers/gpu/drm/bridge/generic-gpio-mux.c | 306 ++++++++++++++++++
6 files changed, 678 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c
create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c
--
2.24.0.525.g8f36a354ae-goog
From: Nicolas Boichat <[email protected]>
Add support for analogix,anx7688
Signed-off-by: Nicolas Boichat <[email protected]>
Signed-off-by: Hsin-Yi Wang <[email protected]>
---
Change from RFC to v1:
- txt to yaml
---
.../bindings/display/bridge/anx7688.yaml | 60 +++++++++++++++++++
1 file changed, 60 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
new file mode 100644
index 000000000000..cf79f7cf8fdf
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/anx7688.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analogix ANX7688 SlimPort (Single-Chip Transmitter for DP over USB-C)
+
+maintainers:
+ - Nicolas Boichat <[email protected]>
+
+description: |
+ The ANX7688 is a single-chip mobile transmitter to support 4K 60 frames per
+ second (4096x2160p60) or FHD 120 frames per second (1920x1080p120) video
+ resolution from a smartphone or tablet with full function USB-C.
+
+ This binding only describes the HDMI to DP display bridge.
+
+properties:
+ compatible:
+ const: analogix,anx7688
+
+ reg:
+ maxItems: 1
+ description: I2C address of the device
+
+ ports:
+ type: object
+
+ properties:
+ port@0:
+ type: object
+ description: |
+ Video port for HDMI input
+
+ port@1:
+ type: object
+ description: |
+ Video port for eDP output
+
+ required:
+ - port@0
+
+required:
+ - compatible
+ - reg
+ - ports
+
+examples:
+ - |
+ anx7688: anx7688@2c {
+ compatible = "analogix,anx7688";
+ reg = <0x2c>;
+
+ port {
+ anx7688_in: endpoint {
+ remote-endpoint = <&hdmi0_out>;
+ };
+ };
+ };
--
2.24.0.525.g8f36a354ae-goog
From: Nicolas Boichat <[email protected]>
ANX7688 is a HDMI to DP converter (as well as USB-C port controller),
that has an internal microcontroller.
The only reason a Linux kernel driver is necessary is to reject
resolutions that require more bandwidth than what is available on
the DP side. DP bandwidth and lane count are reported by the bridge
via 2 registers on I2C.
Signed-off-by: Nicolas Boichat <[email protected]>
Signed-off-by: Hsin-Yi Wang <[email protected]>
---
drivers/gpu/drm/bridge/Kconfig | 9 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++++++++++++
3 files changed, 212 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 34362976cd6f..1f3fc6bec842 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -16,6 +16,15 @@ config DRM_PANEL_BRIDGE
menu "Display Interface Bridges"
depends on DRM && DRM_BRIDGE
+config DRM_ANALOGIX_ANX7688
+ tristate "Analogix ANX7688 bridge"
+ select DRM_KMS_HELPER
+ select REGMAP_I2C
+ ---help---
+ ANX7688 is a transmitter to support DisplayPort over USB-C for
+ smartphone and tablets.
+ This driver only supports the HDMI to DP component of the chip.
+
config DRM_ANALOGIX_ANX78XX
tristate "Analogix ANX78XX bridge"
select DRM_KMS_HELPER
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 4934fcf5a6f8..7a1e0ec032e6 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -1,4 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c
new file mode 100644
index 000000000000..baaed48d6201
--- /dev/null
+++ b/drivers/gpu/drm/bridge/analogix-anx7688.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ANX7688 HDMI->DP bridge driver
+ *
+ * Copyright 2016 Google LLC
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <drm/drm_bridge.h>
+
+/* Register addresses */
+#define VENDOR_ID_REG 0x00
+#define DEVICE_ID_REG 0x02
+
+#define FW_VERSION_REG 0x80
+
+#define DP_BANDWIDTH_REG 0x85
+#define DP_LANE_COUNT_REG 0x86
+
+#define VENDOR_ID 0x1f29
+#define DEVICE_ID 0x7688
+
+/* First supported firmware version (0.85) */
+#define MINIMUM_FW_VERSION 0x0085
+
+struct anx7688 {
+ struct drm_bridge bridge;
+ struct i2c_client *client;
+ struct regmap *regmap;
+
+ bool filter;
+};
+
+static inline struct anx7688 *bridge_to_anx7688(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct anx7688, bridge);
+}
+
+static bool anx7688_bridge_mode_fixup(struct drm_bridge *bridge,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ struct anx7688 *anx7688 = bridge_to_anx7688(bridge);
+ u8 regs[2];
+ u8 dpbw, lanecount;
+ int totalbw, requiredbw;
+ int ret;
+
+ if (!anx7688->filter)
+ return true;
+
+ /* Read both regs 0x85 (bandwidth) and 0x86 (lane count). */
+ ret = regmap_bulk_read(anx7688->regmap, DP_BANDWIDTH_REG, regs, 2);
+ if (ret < 0) {
+ dev_err(&anx7688->client->dev,
+ "Failed to read bandwidth/lane count\n");
+ return false;
+ }
+ dpbw = regs[0];
+ lanecount = regs[1];
+
+ /* Maximum 0x19 bandwidth (6.75 Gbps Turbo mode), 2 lanes */
+ if (dpbw > 0x19 || lanecount > 2) {
+ dev_err(&anx7688->client->dev,
+ "Invalid bandwidth/lane count (%02x/%d)\n",
+ dpbw, lanecount);
+ return false;
+ }
+
+ /* Compute available bandwidth (kHz) */
+ totalbw = dpbw * lanecount * 270000 * 8 / 10;
+
+ /* Required bandwidth (8 bpc, kHz) */
+ requiredbw = mode->clock * 8 * 3;
+
+ dev_dbg(&anx7688->client->dev,
+ "DP bandwidth: %d kHz (%02x/%d); mode requires %d Khz\n",
+ totalbw, dpbw, lanecount, requiredbw);
+
+ if (totalbw == 0) {
+ dev_warn(&anx7688->client->dev,
+ "Bandwidth/lane count are 0, not rejecting modes\n");
+ return true;
+ }
+
+ return totalbw >= requiredbw;
+}
+
+static const struct drm_bridge_funcs anx7688_bridge_funcs = {
+ .mode_fixup = anx7688_bridge_mode_fixup,
+};
+
+static const struct regmap_config anx7688_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static int anx7688_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct anx7688 *anx7688;
+ struct device *dev = &client->dev;
+ int ret;
+ u8 buffer[4];
+ u16 vendor, device, fwversion;
+
+ anx7688 = devm_kzalloc(dev, sizeof(*anx7688), GFP_KERNEL);
+ if (!anx7688)
+ return -ENOMEM;
+
+#if IS_ENABLED(CONFIG_OF)
+ anx7688->bridge.of_node = client->dev.of_node;
+#endif
+
+ anx7688->client = client;
+ i2c_set_clientdata(client, anx7688);
+
+ anx7688->regmap =
+ devm_regmap_init_i2c(client, &anx7688_regmap_config);
+
+ /* Read both vendor and device id (4 bytes). */
+ ret = regmap_bulk_read(anx7688->regmap, VENDOR_ID_REG, buffer, 4);
+ if (ret) {
+ dev_err(dev, "Failed to read chip vendor/device id\n");
+ return ret;
+ }
+
+ vendor = (u16)buffer[1] << 8 | buffer[0];
+ device = (u16)buffer[3] << 8 | buffer[2];
+ if (vendor != VENDOR_ID || device != DEVICE_ID) {
+ dev_err(dev, "Invalid vendor/device id %04x/%04x\n",
+ vendor, device);
+ return -ENODEV;
+ }
+
+ ret = regmap_bulk_read(anx7688->regmap, FW_VERSION_REG, buffer, 2);
+ if (ret) {
+ dev_err(&client->dev, "Failed to read firmware version\n");
+ return ret;
+ }
+
+ fwversion = (u16)buffer[0] << 8 | buffer[1];
+ dev_info(dev, "ANX7688 firwmare version %02x.%02x\n",
+ buffer[0], buffer[1]);
+
+ /* FW version >= 0.85 supports bandwidth/lane count registers */
+ if (fwversion >= MINIMUM_FW_VERSION) {
+ anx7688->filter = true;
+ } else {
+ /* Warn, but not fail, for backwards compatibility. */
+ dev_warn(dev,
+ "Old ANX7688 FW version (%02x.%02x), not filtering\n",
+ buffer[0], buffer[1]);
+ }
+
+ anx7688->bridge.funcs = &anx7688_bridge_funcs;
+ drm_bridge_add(&anx7688->bridge);
+
+ return 0;
+}
+
+static int anx7688_i2c_remove(struct i2c_client *client)
+{
+ struct anx7688 *anx7688 = i2c_get_clientdata(client);
+
+ drm_bridge_remove(&anx7688->bridge);
+
+ return 0;
+}
+
+static const struct i2c_device_id anx7688_id[] = {
+ { "anx7688", 0 },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(i2c, anx7688_id);
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id anx7688_match_table[] = {
+ { .compatible = "analogix,anx7688", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, anx7688_match_table);
+#endif
+
+static struct i2c_driver anx7688_driver = {
+ .driver = {
+ .name = "anx7688",
+ .of_match_table = of_match_ptr(anx7688_match_table),
+ },
+ .probe = anx7688_i2c_probe,
+ .remove = anx7688_i2c_remove,
+ .id_table = anx7688_id,
+};
+
+module_i2c_driver(anx7688_driver);
+
+MODULE_DESCRIPTION("ANX7688 SlimPort Transmitter driver");
+MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
+MODULE_LICENSE("GPL v2");
--
2.24.0.525.g8f36a354ae-goog
From: Nicolas Boichat <[email protected]>
Add bindings for Generic GPIO mux driver.
Signed-off-by: Nicolas Boichat <[email protected]>
Signed-off-by: Hsin-Yi Wang <[email protected]>
---
Change from RFC to v1:
- txt to yaml
---
.../bindings/display/bridge/gpio-mux.yaml | 89 +++++++++++++++++++
1 file changed, 89 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
diff --git a/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
new file mode 100644
index 000000000000..cef098749066
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/gpio-mux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic display mux (1 input, 2 outputs)
+
+maintainers:
+ - Nicolas Boichat <[email protected]>
+
+description: |
+ This bindings describes a simple display (e.g. HDMI) mux, that has 1
+ input, and 2 outputs. The mux status is controlled by hardware, and
+ its status is read back using a GPIO.
+
+properties:
+ compatible:
+ const: gpio-display-mux
+
+ detect-gpios:
+ maxItems: 1
+ description: GPIO that indicates the active output
+
+ ports:
+ type: object
+
+ properties:
+ port@0:
+ type: object
+ description: |
+ Video port for input.
+
+ port@1:
+ type: object
+ description: |
+ 2 video ports for output.
+ The reg value in the endpoints matches the GPIO status: when
+ GPIO is asserted, endpoint with reg value <1> is selected.
+
+ required:
+ - port@0
+ - port@1
+
+required:
+ - compatible
+ - detect-gpios
+ - ports
+
+examples:
+ - |
+ hdmi_mux: hdmi_mux {
+ compatible = "gpio-display-mux";
+ status = "okay";
+ detect-gpios = <&pio 36 GPIO_ACTIVE_HIGH>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&hdmi_mux_pins>;
+ ddc-i2c-bus = <&hdmiddc0>;
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 { /* input */
+ reg = <0>;
+
+ hdmi_mux_in: endpoint {
+ remote-endpoint = <&hdmi0_out>;
+ };
+ };
+
+ port@1 { /* output */
+ reg = <1>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ hdmi_mux_out_anx: endpoint@0 {
+ reg = <0>;
+ remote-endpoint = <&anx7688_in>;
+ };
+
+ hdmi_mux_out_hdmi: endpoint@1 {
+ reg = <1>;
+ remote-endpoint = <&hdmi_connector_in>;
+ };
+ };
+ };
+ };
--
2.24.0.525.g8f36a354ae-goog
From: Nicolas Boichat <[email protected]>
This driver supports single input, 2 output display mux (e.g.
HDMI mux), that provide its status via a GPIO.
Signed-off-by: Nicolas Boichat <[email protected]>
Signed-off-by: Hsin-Yi Wang <[email protected]>
---
drivers/gpu/drm/bridge/Kconfig | 10 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/generic-gpio-mux.c | 306 ++++++++++++++++++++++
3 files changed, 317 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 1f3fc6bec842..4734f6993858 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -54,6 +54,16 @@ config DRM_DUMB_VGA_DAC
Support for non-programmable RGB to VGA DAC bridges, such as ADI
ADV7123, TI THS8134 and THS8135 or passive resistor ladder DACs.
+config DRM_GENERIC_GPIO_MUX
+ tristate "Generic GPIO-controlled mux"
+ depends on OF
+ select DRM_KMS_HELPER
+ ---help---
+ This bridge driver models a GPIO-controlled display mux with one
+ input, 2 outputs (e.g. an HDMI mux). The hardware decides which output
+ is active, reports it as a GPIO, and the driver redirects calls to the
+ appropriate downstream bridge (if any).
+
config DRM_LVDS_ENCODER
tristate "Transparent parallel to LVDS encoder support"
depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 7a1e0ec032e6..1c0c92667ac4 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
+obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o
obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o
obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
diff --git a/drivers/gpu/drm/bridge/generic-gpio-mux.c b/drivers/gpu/drm/bridge/generic-gpio-mux.c
new file mode 100644
index 000000000000..ba08321dcc17
--- /dev/null
+++ b/drivers/gpu/drm/bridge/generic-gpio-mux.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic gpio mux bridge driver
+ *
+ * Copyright 2016 Google LLC
+ */
+
+
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_graph.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_probe_helper.h>
+
+struct gpio_display_mux {
+ struct device *dev;
+
+ struct gpio_desc *gpiod_detect;
+ int detect_irq;
+
+ struct drm_bridge bridge;
+
+ struct drm_bridge *next[2];
+};
+
+static inline struct gpio_display_mux *bridge_to_gpio_display_mux(
+ struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct gpio_display_mux, bridge);
+}
+
+static irqreturn_t gpio_display_mux_det_threaded_handler(int unused, void *data)
+{
+ struct gpio_display_mux *gpio_display_mux = data;
+ int active = gpiod_get_value(gpio_display_mux->gpiod_detect);
+
+ dev_dbg(gpio_display_mux->dev, "Interrupt %d!\n", active);
+
+ if (gpio_display_mux->bridge.dev)
+ drm_kms_helper_hotplug_event(gpio_display_mux->bridge.dev);
+
+ return IRQ_HANDLED;
+}
+
+static int gpio_display_mux_attach(struct drm_bridge *bridge)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ struct drm_bridge *next;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
+ next = gpio_display_mux->next[i];
+ if (next)
+ next->encoder = bridge->encoder;
+ }
+
+ return 0;
+}
+
+static bool gpio_display_mux_mode_fixup(struct drm_bridge *bridge,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ int active;
+ struct drm_bridge *next;
+
+ active = gpiod_get_value(gpio_display_mux->gpiod_detect);
+ next = gpio_display_mux->next[active];
+
+ if (next && next->funcs->mode_fixup)
+ return next->funcs->mode_fixup(next, mode, adjusted_mode);
+ else
+ return true;
+}
+
+static void gpio_display_mux_mode_set(struct drm_bridge *bridge,
+ struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ int active;
+ struct drm_bridge *next;
+
+ active = gpiod_get_value(gpio_display_mux->gpiod_detect);
+ next = gpio_display_mux->next[active];
+
+ if (next && next->funcs->mode_set)
+ next->funcs->mode_set(next, mode, adjusted_mode);
+}
+
+/**
+ * Since this driver _reacts_ to mux changes, we need to make sure all
+ * downstream bridges are pre-enabled.
+ */
+static void gpio_display_mux_pre_enable(struct drm_bridge *bridge)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ struct drm_bridge *next;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
+ next = gpio_display_mux->next[i];
+ if (next && next->funcs->pre_enable)
+ next->funcs->pre_enable(next);
+ }
+}
+
+static void gpio_display_mux_post_disable(struct drm_bridge *bridge)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ struct drm_bridge *next;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
+ next = gpio_display_mux->next[i];
+ if (next && next->funcs->post_disable)
+ next->funcs->post_disable(next);
+ }
+}
+
+/**
+ * In an ideal mux driver, only the currently selected bridge should be enabled.
+ * For the sake of simplicity, we just just enable/disable all downstream
+ * bridges at the same time.
+ */
+static void gpio_display_mux_enable(struct drm_bridge *bridge)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ struct drm_bridge *next;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
+ next = gpio_display_mux->next[i];
+ if (next && next->funcs->enable)
+ next->funcs->enable(next);
+ }
+}
+
+static void gpio_display_mux_disable(struct drm_bridge *bridge)
+{
+ struct gpio_display_mux *gpio_display_mux =
+ bridge_to_gpio_display_mux(bridge);
+ struct drm_bridge *next;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
+ next = gpio_display_mux->next[i];
+ if (next && next->funcs->disable)
+ next->funcs->disable(next);
+ }
+}
+
+static const struct drm_bridge_funcs gpio_display_mux_bridge_funcs = {
+ .attach = gpio_display_mux_attach,
+ .mode_fixup = gpio_display_mux_mode_fixup,
+ .disable = gpio_display_mux_disable,
+ .post_disable = gpio_display_mux_post_disable,
+ .mode_set = gpio_display_mux_mode_set,
+ .pre_enable = gpio_display_mux_pre_enable,
+ .enable = gpio_display_mux_enable,
+};
+
+static int gpio_display_mux_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct gpio_display_mux *gpio_display_mux;
+ struct device_node *port, *ep, *remote;
+ int ret;
+ u32 reg;
+
+ gpio_display_mux = devm_kzalloc(dev, sizeof(*gpio_display_mux),
+ GFP_KERNEL);
+ if (!gpio_display_mux)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, gpio_display_mux);
+ gpio_display_mux->dev = &pdev->dev;
+
+ gpio_display_mux->bridge.of_node = dev->of_node;
+
+ gpio_display_mux->gpiod_detect =
+ devm_gpiod_get(dev, "detect", GPIOD_IN);
+ if (IS_ERR(gpio_display_mux->gpiod_detect))
+ return PTR_ERR(gpio_display_mux->gpiod_detect);
+
+ gpio_display_mux->detect_irq =
+ gpiod_to_irq(gpio_display_mux->gpiod_detect);
+ if (gpio_display_mux->detect_irq < 0) {
+ dev_err(dev, "Failed to get output irq %d\n",
+ gpio_display_mux->detect_irq);
+ return -ENODEV;
+ }
+
+ port = of_graph_get_port_by_id(dev->of_node, 1);
+ if (!port) {
+ dev_err(dev, "Missing output port node\n");
+ return -EINVAL;
+ }
+
+ for_each_child_of_node(port, ep) {
+ if (!ep->name || (of_node_cmp(ep->name, "endpoint") != 0)) {
+ of_node_put(ep);
+ continue;
+ }
+
+ if (of_property_read_u32(ep, "reg", ®) < 0 ||
+ reg >= ARRAY_SIZE(gpio_display_mux->next)) {
+ dev_err(dev,
+ "Missing/invalid reg property for endpoint %s\n",
+ ep->full_name);
+ of_node_put(ep);
+ of_node_put(port);
+ return -EINVAL;
+ }
+
+ remote = of_graph_get_remote_port_parent(ep);
+ if (!remote) {
+ dev_err(dev,
+ "Missing connector/bridge node for endpoint %s\n",
+ ep->full_name);
+ of_node_put(ep);
+ of_node_put(port);
+ return -EINVAL;
+ }
+ of_node_put(ep);
+
+ if (of_device_is_compatible(remote, "hdmi-connector")) {
+ of_node_put(remote);
+ continue;
+ }
+
+ gpio_display_mux->next[reg] = of_drm_find_bridge(remote);
+ if (!gpio_display_mux->next[reg]) {
+ dev_err(dev, "Waiting for external bridge %s\n",
+ remote->name);
+ of_node_put(remote);
+ of_node_put(port);
+ return -EPROBE_DEFER;
+ }
+
+ of_node_put(remote);
+ }
+ of_node_put(port);
+
+ gpio_display_mux->bridge.funcs = &gpio_display_mux_bridge_funcs;
+ drm_bridge_add(&gpio_display_mux->bridge);
+
+ ret = devm_request_threaded_irq(dev, gpio_display_mux->detect_irq,
+ NULL,
+ gpio_display_mux_det_threaded_handler,
+ IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
+ IRQF_ONESHOT,
+ "gpio-display-mux-det", gpio_display_mux);
+ if (ret) {
+ dev_err(dev, "Failed to request MUX_DET threaded irq\n");
+ goto err_bridge_remove;
+ }
+
+ return 0;
+
+err_bridge_remove:
+ drm_bridge_remove(&gpio_display_mux->bridge);
+
+ return ret;
+}
+
+static int gpio_display_mux_remove(struct platform_device *pdev)
+{
+ struct gpio_display_mux *gpio_display_mux = platform_get_drvdata(pdev);
+
+ drm_bridge_remove(&gpio_display_mux->bridge);
+
+ return 0;
+}
+
+static const struct of_device_id gpio_display_mux_match[] = {
+ { .compatible = "gpio-display-mux", },
+ {},
+};
+
+struct platform_driver gpio_display_mux_driver = {
+ .probe = gpio_display_mux_probe,
+ .remove = gpio_display_mux_remove,
+ .driver = {
+ .name = "gpio-display-mux",
+ .of_match_table = gpio_display_mux_match,
+ },
+};
+
+module_platform_driver(gpio_display_mux_driver);
+
+MODULE_DESCRIPTION("GPIO-controlled display mux");
+MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
+MODULE_LICENSE("GPL v2");
--
2.24.0.525.g8f36a354ae-goog
Hi Hsin-Yi,
On 11/12/19 7:19, Hsin-Yi Wang wrote:
> From: Nicolas Boichat <[email protected]>
>
> ANX7688 is a HDMI to DP converter (as well as USB-C port controller),
> that has an internal microcontroller.
>
> The only reason a Linux kernel driver is necessary is to reject
> resolutions that require more bandwidth than what is available on
> the DP side. DP bandwidth and lane count are reported by the bridge
> via 2 registers on I2C.
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
> ---
Although I am not a drm expert I did an initial review of this patch before
sending and looks good to me now. Also I just tested with current mainline on my
ELM device and I am happy to have display now, so thanks for sending this upstream:
Tested-by: Enric Balletbo i Serra <[email protected]>
> drivers/gpu/drm/bridge/Kconfig | 9 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++++++++++++
> 3 files changed, 212 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 34362976cd6f..1f3fc6bec842 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -16,6 +16,15 @@ config DRM_PANEL_BRIDGE
> menu "Display Interface Bridges"
> depends on DRM && DRM_BRIDGE
>
> +config DRM_ANALOGIX_ANX7688
> + tristate "Analogix ANX7688 bridge"
> + select DRM_KMS_HELPER
> + select REGMAP_I2C
> + ---help---
> + ANX7688 is a transmitter to support DisplayPort over USB-C for
> + smartphone and tablets.
> + This driver only supports the HDMI to DP component of the chip.
> +
> config DRM_ANALOGIX_ANX78XX
> tristate "Analogix ANX78XX bridge"
> select DRM_KMS_HELPER
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 4934fcf5a6f8..7a1e0ec032e6 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
> obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
> obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c
> new file mode 100644
> index 000000000000..baaed48d6201
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/analogix-anx7688.c
> @@ -0,0 +1,202 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ANX7688 HDMI->DP bridge driver
> + *
> + * Copyright 2016 Google LLC
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <drm/drm_bridge.h>
> +
> +/* Register addresses */
> +#define VENDOR_ID_REG 0x00
> +#define DEVICE_ID_REG 0x02
> +
> +#define FW_VERSION_REG 0x80
> +
> +#define DP_BANDWIDTH_REG 0x85
> +#define DP_LANE_COUNT_REG 0x86
> +
> +#define VENDOR_ID 0x1f29
> +#define DEVICE_ID 0x7688
> +
> +/* First supported firmware version (0.85) */
> +#define MINIMUM_FW_VERSION 0x0085
> +
> +struct anx7688 {
> + struct drm_bridge bridge;
> + struct i2c_client *client;
> + struct regmap *regmap;
> +
> + bool filter;
> +};
> +
> +static inline struct anx7688 *bridge_to_anx7688(struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct anx7688, bridge);
> +}
> +
> +static bool anx7688_bridge_mode_fixup(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct anx7688 *anx7688 = bridge_to_anx7688(bridge);
> + u8 regs[2];
> + u8 dpbw, lanecount;
> + int totalbw, requiredbw;
> + int ret;
> +
> + if (!anx7688->filter)
> + return true;
> +
> + /* Read both regs 0x85 (bandwidth) and 0x86 (lane count). */
> + ret = regmap_bulk_read(anx7688->regmap, DP_BANDWIDTH_REG, regs, 2);
> + if (ret < 0) {
> + dev_err(&anx7688->client->dev,
> + "Failed to read bandwidth/lane count\n");
> + return false;
> + }
> + dpbw = regs[0];
> + lanecount = regs[1];
> +
> + /* Maximum 0x19 bandwidth (6.75 Gbps Turbo mode), 2 lanes */
> + if (dpbw > 0x19 || lanecount > 2) {
> + dev_err(&anx7688->client->dev,
> + "Invalid bandwidth/lane count (%02x/%d)\n",
> + dpbw, lanecount);
> + return false;
> + }
> +
> + /* Compute available bandwidth (kHz) */
> + totalbw = dpbw * lanecount * 270000 * 8 / 10;
> +
> + /* Required bandwidth (8 bpc, kHz) */
> + requiredbw = mode->clock * 8 * 3;
> +
> + dev_dbg(&anx7688->client->dev,
> + "DP bandwidth: %d kHz (%02x/%d); mode requires %d Khz\n",
> + totalbw, dpbw, lanecount, requiredbw);
> +
> + if (totalbw == 0) {
> + dev_warn(&anx7688->client->dev,
> + "Bandwidth/lane count are 0, not rejecting modes\n");
> + return true;
> + }
> +
> + return totalbw >= requiredbw;
> +}
> +
> +static const struct drm_bridge_funcs anx7688_bridge_funcs = {
> + .mode_fixup = anx7688_bridge_mode_fixup,
> +};
> +
> +static const struct regmap_config anx7688_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +};
> +
> +static int anx7688_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct anx7688 *anx7688;
> + struct device *dev = &client->dev;
> + int ret;
> + u8 buffer[4];
> + u16 vendor, device, fwversion;
> +
> + anx7688 = devm_kzalloc(dev, sizeof(*anx7688), GFP_KERNEL);
> + if (!anx7688)
> + return -ENOMEM;
> +
> +#if IS_ENABLED(CONFIG_OF)
> + anx7688->bridge.of_node = client->dev.of_node;
> +#endif
> +
> + anx7688->client = client;
> + i2c_set_clientdata(client, anx7688);
> +
> + anx7688->regmap =
> + devm_regmap_init_i2c(client, &anx7688_regmap_config);
> +
> + /* Read both vendor and device id (4 bytes). */
> + ret = regmap_bulk_read(anx7688->regmap, VENDOR_ID_REG, buffer, 4);
> + if (ret) {
> + dev_err(dev, "Failed to read chip vendor/device id\n");
> + return ret;
> + }
> +
> + vendor = (u16)buffer[1] << 8 | buffer[0];
> + device = (u16)buffer[3] << 8 | buffer[2];
> + if (vendor != VENDOR_ID || device != DEVICE_ID) {
> + dev_err(dev, "Invalid vendor/device id %04x/%04x\n",
> + vendor, device);
> + return -ENODEV;
> + }
> +
> + ret = regmap_bulk_read(anx7688->regmap, FW_VERSION_REG, buffer, 2);
> + if (ret) {
> + dev_err(&client->dev, "Failed to read firmware version\n");
> + return ret;
> + }
> +
> + fwversion = (u16)buffer[0] << 8 | buffer[1];
> + dev_info(dev, "ANX7688 firwmare version %02x.%02x\n",
> + buffer[0], buffer[1]);
> +
> + /* FW version >= 0.85 supports bandwidth/lane count registers */
> + if (fwversion >= MINIMUM_FW_VERSION) {
> + anx7688->filter = true;
> + } else {
> + /* Warn, but not fail, for backwards compatibility. */
> + dev_warn(dev,
> + "Old ANX7688 FW version (%02x.%02x), not filtering\n",
> + buffer[0], buffer[1]);
> + }
> +
> + anx7688->bridge.funcs = &anx7688_bridge_funcs;
> + drm_bridge_add(&anx7688->bridge);
> +
> + return 0;
> +}
> +
> +static int anx7688_i2c_remove(struct i2c_client *client)
> +{
> + struct anx7688 *anx7688 = i2c_get_clientdata(client);
> +
> + drm_bridge_remove(&anx7688->bridge);
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id anx7688_id[] = {
> + { "anx7688", 0 },
> + { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, anx7688_id);
> +
> +#if IS_ENABLED(CONFIG_OF)
> +static const struct of_device_id anx7688_match_table[] = {
> + { .compatible = "analogix,anx7688", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, anx7688_match_table);
> +#endif
> +
> +static struct i2c_driver anx7688_driver = {
> + .driver = {
> + .name = "anx7688",
> + .of_match_table = of_match_ptr(anx7688_match_table),
> + },
> + .probe = anx7688_i2c_probe,
> + .remove = anx7688_i2c_remove,
> + .id_table = anx7688_id,
> +};
> +
> +module_i2c_driver(anx7688_driver);
> +
> +MODULE_DESCRIPTION("ANX7688 SlimPort Transmitter driver");
> +MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
> +MODULE_LICENSE("GPL v2");
>
Hi Hsin-Yi,
On 11/12/19 7:19, Hsin-Yi Wang wrote:
> From: Nicolas Boichat <[email protected]>
>
> This driver supports single input, 2 output display mux (e.g.
> HDMI mux), that provide its status via a GPIO.
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
I'll let drm maintainers comment on this but if that's the way to go you can add my:
Tested-by: Enric Balletbo i Serra <[email protected]>
Only one issue that needs to be solved in next version, see below.
> ---
> drivers/gpu/drm/bridge/Kconfig | 10 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/generic-gpio-mux.c | 306 ++++++++++++++++++++++
> 3 files changed, 317 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 1f3fc6bec842..4734f6993858 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -54,6 +54,16 @@ config DRM_DUMB_VGA_DAC
> Support for non-programmable RGB to VGA DAC bridges, such as ADI
> ADV7123, TI THS8134 and THS8135 or passive resistor ladder DACs.
>
> +config DRM_GENERIC_GPIO_MUX
> + tristate "Generic GPIO-controlled mux"
> + depends on OF
> + select DRM_KMS_HELPER
> + ---help---
> + This bridge driver models a GPIO-controlled display mux with one
> + input, 2 outputs (e.g. an HDMI mux). The hardware decides which output
> + is active, reports it as a GPIO, and the driver redirects calls to the
> + appropriate downstream bridge (if any).
> +
> config DRM_LVDS_ENCODER
> tristate "Transparent parallel to LVDS encoder support"
> depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 7a1e0ec032e6..1c0c92667ac4 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
> obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
> obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> +obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o
> obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o
> obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
> diff --git a/drivers/gpu/drm/bridge/generic-gpio-mux.c b/drivers/gpu/drm/bridge/generic-gpio-mux.c
> new file mode 100644
> index 000000000000..ba08321dcc17
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/generic-gpio-mux.c
> @@ -0,0 +1,306 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Generic gpio mux bridge driver
> + *
> + * Copyright 2016 Google LLC
> + */
> +
> +
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_graph.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_probe_helper.h>
> +
> +struct gpio_display_mux {
> + struct device *dev;
> +
> + struct gpio_desc *gpiod_detect;
> + int detect_irq;
> +
> + struct drm_bridge bridge;
> +
> + struct drm_bridge *next[2];
> +};
> +
> +static inline struct gpio_display_mux *bridge_to_gpio_display_mux(
> + struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct gpio_display_mux, bridge);
> +}
> +
> +static irqreturn_t gpio_display_mux_det_threaded_handler(int unused, void *data)
> +{
> + struct gpio_display_mux *gpio_display_mux = data;
> + int active = gpiod_get_value(gpio_display_mux->gpiod_detect);
> +
> + dev_dbg(gpio_display_mux->dev, "Interrupt %d!\n", active);
> +
> + if (gpio_display_mux->bridge.dev)
> + drm_kms_helper_hotplug_event(gpio_display_mux->bridge.dev);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int gpio_display_mux_attach(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next)
> + next->encoder = bridge->encoder;
> + }
> +
> + return 0;
> +}
> +
> +static bool gpio_display_mux_mode_fixup(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + int active;
> + struct drm_bridge *next;
> +
> + active = gpiod_get_value(gpio_display_mux->gpiod_detect);
> + next = gpio_display_mux->next[active];
> +
> + if (next && next->funcs->mode_fixup)
> + return next->funcs->mode_fixup(next, mode, adjusted_mode);
> + else
> + return true;
> +}
> +
> +static void gpio_display_mux_mode_set(struct drm_bridge *bridge,
> + struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
Those two need to be const now.
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + int active;
> + struct drm_bridge *next;
> +
> + active = gpiod_get_value(gpio_display_mux->gpiod_detect);
> + next = gpio_display_mux->next[active];
> +
> + if (next && next->funcs->mode_set)
> + next->funcs->mode_set(next, mode, adjusted_mode);
> +}
> +
> +/**
> + * Since this driver _reacts_ to mux changes, we need to make sure all
> + * downstream bridges are pre-enabled.
> + */
> +static void gpio_display_mux_pre_enable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->pre_enable)
> + next->funcs->pre_enable(next);
> + }
> +}
> +
> +static void gpio_display_mux_post_disable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->post_disable)
> + next->funcs->post_disable(next);
> + }
> +}
> +
> +/**
> + * In an ideal mux driver, only the currently selected bridge should be enabled.
> + * For the sake of simplicity, we just just enable/disable all downstream
> + * bridges at the same time.
> + */
> +static void gpio_display_mux_enable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->enable)
> + next->funcs->enable(next);
> + }
> +}
> +
> +static void gpio_display_mux_disable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->disable)
> + next->funcs->disable(next);
> + }
> +}
> +
> +static const struct drm_bridge_funcs gpio_display_mux_bridge_funcs = {
> + .attach = gpio_display_mux_attach,
> + .mode_fixup = gpio_display_mux_mode_fixup,
> + .disable = gpio_display_mux_disable,
> + .post_disable = gpio_display_mux_post_disable,
> + .mode_set = gpio_display_mux_mode_set,
> + .pre_enable = gpio_display_mux_pre_enable,
> + .enable = gpio_display_mux_enable,
> +};
> +
> +static int gpio_display_mux_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct gpio_display_mux *gpio_display_mux;
> + struct device_node *port, *ep, *remote;
> + int ret;
> + u32 reg;
> +
> + gpio_display_mux = devm_kzalloc(dev, sizeof(*gpio_display_mux),
> + GFP_KERNEL);
> + if (!gpio_display_mux)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, gpio_display_mux);
> + gpio_display_mux->dev = &pdev->dev;
> +
> + gpio_display_mux->bridge.of_node = dev->of_node;
> +
> + gpio_display_mux->gpiod_detect =
> + devm_gpiod_get(dev, "detect", GPIOD_IN);
> + if (IS_ERR(gpio_display_mux->gpiod_detect))
> + return PTR_ERR(gpio_display_mux->gpiod_detect);
> +
> + gpio_display_mux->detect_irq =
> + gpiod_to_irq(gpio_display_mux->gpiod_detect);
> + if (gpio_display_mux->detect_irq < 0) {
> + dev_err(dev, "Failed to get output irq %d\n",
> + gpio_display_mux->detect_irq);
> + return -ENODEV;
> + }
> +
> + port = of_graph_get_port_by_id(dev->of_node, 1);
> + if (!port) {
> + dev_err(dev, "Missing output port node\n");
> + return -EINVAL;
> + }
> +
> + for_each_child_of_node(port, ep) {
> + if (!ep->name || (of_node_cmp(ep->name, "endpoint") != 0)) {
> + of_node_put(ep);
> + continue;
> + }
> +
> + if (of_property_read_u32(ep, "reg", ®) < 0 ||
> + reg >= ARRAY_SIZE(gpio_display_mux->next)) {
> + dev_err(dev,
> + "Missing/invalid reg property for endpoint %s\n",
> + ep->full_name);
> + of_node_put(ep);
> + of_node_put(port);
> + return -EINVAL;
> + }
> +
> + remote = of_graph_get_remote_port_parent(ep);
> + if (!remote) {
> + dev_err(dev,
> + "Missing connector/bridge node for endpoint %s\n",
> + ep->full_name);
> + of_node_put(ep);
> + of_node_put(port);
> + return -EINVAL;
> + }
> + of_node_put(ep);
> +
> + if (of_device_is_compatible(remote, "hdmi-connector")) {
> + of_node_put(remote);
> + continue;
> + }
> +
> + gpio_display_mux->next[reg] = of_drm_find_bridge(remote);
> + if (!gpio_display_mux->next[reg]) {
> + dev_err(dev, "Waiting for external bridge %s\n",
> + remote->name);
> + of_node_put(remote);
> + of_node_put(port);
> + return -EPROBE_DEFER;
> + }
> +
> + of_node_put(remote);
> + }
> + of_node_put(port);
> +
> + gpio_display_mux->bridge.funcs = &gpio_display_mux_bridge_funcs;
> + drm_bridge_add(&gpio_display_mux->bridge);
> +
> + ret = devm_request_threaded_irq(dev, gpio_display_mux->detect_irq,
> + NULL,
> + gpio_display_mux_det_threaded_handler,
> + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> + IRQF_ONESHOT,
> + "gpio-display-mux-det", gpio_display_mux);
> + if (ret) {
> + dev_err(dev, "Failed to request MUX_DET threaded irq\n");
> + goto err_bridge_remove;
> + }
> +
> + return 0;
> +
> +err_bridge_remove:
> + drm_bridge_remove(&gpio_display_mux->bridge);
> +
> + return ret;
> +}
> +
> +static int gpio_display_mux_remove(struct platform_device *pdev)
> +{
> + struct gpio_display_mux *gpio_display_mux = platform_get_drvdata(pdev);
> +
> + drm_bridge_remove(&gpio_display_mux->bridge);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id gpio_display_mux_match[] = {
> + { .compatible = "gpio-display-mux", },
> + {},
> +};
> +
> +struct platform_driver gpio_display_mux_driver = {
> + .probe = gpio_display_mux_probe,
> + .remove = gpio_display_mux_remove,
> + .driver = {
> + .name = "gpio-display-mux",
> + .of_match_table = gpio_display_mux_match,
> + },
> +};
> +
> +module_platform_driver(gpio_display_mux_driver);
> +
> +MODULE_DESCRIPTION("GPIO-controlled display mux");
> +MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
> +MODULE_LICENSE("GPL v2");
>
On Wed, Dec 11, 2019 at 12:19 AM Hsin-Yi Wang <[email protected]> wrote:
>
> From: Nicolas Boichat <[email protected]>
>
> Add bindings for Generic GPIO mux driver.
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
> ---
> Change from RFC to v1:
> - txt to yaml
> ---
> .../bindings/display/bridge/gpio-mux.yaml | 89 +++++++++++++++++++
> 1 file changed, 89 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> new file mode 100644
> index 000000000000..cef098749066
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/gpio-mux.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic display mux (1 input, 2 outputs)
What makes it generic? Doesn't the mux chip have power supply,
possibly a reset line or not, etc.? What about a mux where the GPIO
controls the mux?
Generally, we avoid 'generic' bindings because h/w is rarely generic.
You can have a generic driver which works on multiple devices.
> +
> +maintainers:
> + - Nicolas Boichat <[email protected]>
> +
> +description: |
> + This bindings describes a simple display (e.g. HDMI) mux, that has 1
> + input, and 2 outputs. The mux status is controlled by hardware, and
> + its status is read back using a GPIO.
> +
> +properties:
> + compatible:
> + const: gpio-display-mux
> +
> + detect-gpios:
> + maxItems: 1
> + description: GPIO that indicates the active output
> +
> + ports:
> + type: object
> +
> + properties:
> + port@0:
> + type: object
> + description: |
> + Video port for input.
> +
> + port@1:
> + type: object
> + description: |
> + 2 video ports for output.
> + The reg value in the endpoints matches the GPIO status: when
> + GPIO is asserted, endpoint with reg value <1> is selected.
You should describe 'endpoint@0' and 'endpoint@1' here too.
> +
> + required:
> + - port@0
> + - port@1
> +
> +required:
> + - compatible
> + - detect-gpios
> + - ports
> +
> +examples:
> + - |
> + hdmi_mux: hdmi_mux {
> + compatible = "gpio-display-mux";
> + status = "okay";
Don't show status in examples.
> + detect-gpios = <&pio 36 GPIO_ACTIVE_HIGH>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&hdmi_mux_pins>;
> + ddc-i2c-bus = <&hdmiddc0>;
Not documented. Is the i2c bus muxed too? If not, then this is in the
wrong place.
> +
> + ports {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + port@0 { /* input */
> + reg = <0>;
> +
> + hdmi_mux_in: endpoint {
> + remote-endpoint = <&hdmi0_out>;
> + };
> + };
> +
> + port@1 { /* output */
> + reg = <1>;
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + hdmi_mux_out_anx: endpoint@0 {
> + reg = <0>;
> + remote-endpoint = <&anx7688_in>;
> + };
> +
> + hdmi_mux_out_hdmi: endpoint@1 {
> + reg = <1>;
> + remote-endpoint = <&hdmi_connector_in>;
> + };
> + };
> + };
> + };
> --
> 2.24.0.525.g8f36a354ae-goog
>
Hi Hsin-Yi and Nicolas,
Thank you for the patch.
On Wed, Dec 11, 2019 at 02:19:11PM +0800, Hsin-Yi Wang wrote:
> From: Nicolas Boichat <[email protected]>
>
> This driver supports single input, 2 output display mux (e.g.
> HDMI mux), that provide its status via a GPIO.
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
> ---
> drivers/gpu/drm/bridge/Kconfig | 10 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/generic-gpio-mux.c | 306 ++++++++++++++++++++++
> 3 files changed, 317 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 1f3fc6bec842..4734f6993858 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -54,6 +54,16 @@ config DRM_DUMB_VGA_DAC
> Support for non-programmable RGB to VGA DAC bridges, such as ADI
> ADV7123, TI THS8134 and THS8135 or passive resistor ladder DACs.
>
> +config DRM_GENERIC_GPIO_MUX
> + tristate "Generic GPIO-controlled mux"
> + depends on OF
> + select DRM_KMS_HELPER
> + ---help---
> + This bridge driver models a GPIO-controlled display mux with one
> + input, 2 outputs (e.g. an HDMI mux). The hardware decides which output
> + is active, reports it as a GPIO, and the driver redirects calls to the
> + appropriate downstream bridge (if any).
My understanding of the issue was that the mux was controllable by a
GPIO, not that the GPIO would report its status. This changes a few
things. How is the mux controlled then ?
> config DRM_LVDS_ENCODER
> tristate "Transparent parallel to LVDS encoder support"
> depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 7a1e0ec032e6..1c0c92667ac4 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
> obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
> obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> +obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o
> obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o
> obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
> diff --git a/drivers/gpu/drm/bridge/generic-gpio-mux.c b/drivers/gpu/drm/bridge/generic-gpio-mux.c
> new file mode 100644
> index 000000000000..ba08321dcc17
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/generic-gpio-mux.c
> @@ -0,0 +1,306 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Generic gpio mux bridge driver
> + *
> + * Copyright 2016 Google LLC
> + */
> +
> +
One blank line is enough.
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_graph.h>
Could you please sort these headers alphabetically ?
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_probe_helper.h>
> +
> +struct gpio_display_mux {
> + struct device *dev;
> +
> + struct gpio_desc *gpiod_detect;
> + int detect_irq;
> +
> + struct drm_bridge bridge;
> +
> + struct drm_bridge *next[2];
> +};
> +
> +static inline struct gpio_display_mux *bridge_to_gpio_display_mux(
> + struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct gpio_display_mux, bridge);
> +}
> +
> +static irqreturn_t gpio_display_mux_det_threaded_handler(int unused, void *data)
> +{
> + struct gpio_display_mux *gpio_display_mux = data;
gpio_display_mux is a long variable name. You can shorten it to mux here
and below.
> + int active = gpiod_get_value(gpio_display_mux->gpiod_detect);
> +
> + dev_dbg(gpio_display_mux->dev, "Interrupt %d!\n", active);
> +
> + if (gpio_display_mux->bridge.dev)
> + drm_kms_helper_hotplug_event(gpio_display_mux->bridge.dev);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int gpio_display_mux_attach(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
i never takes negative values, you can make it an unsigned int.
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next)
> + next->encoder = bridge->encoder;
> + }
> +
> + return 0;
> +}
> +
> +static bool gpio_display_mux_mode_fixup(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + int active;
> + struct drm_bridge *next;
> +
> + active = gpiod_get_value(gpio_display_mux->gpiod_detect);
What if the value of the GPIO changes between, let's say, this operation
and gpio_display_mux_mode_set() ? This doesn't seem very stable to me.
DRM/KMS hasn't been designed to have the output routing configured
externally without any control from the drivers.
> + next = gpio_display_mux->next[active];
This will crash if gpiod_get_value() returns an error. Same for the
other functions below.
> +
> + if (next && next->funcs->mode_fixup)
> + return next->funcs->mode_fixup(next, mode, adjusted_mode);
> + else
> + return true;
> +}
> +
> +static void gpio_display_mux_mode_set(struct drm_bridge *bridge,
> + struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + int active;
> + struct drm_bridge *next;
> +
> + active = gpiod_get_value(gpio_display_mux->gpiod_detect);
> + next = gpio_display_mux->next[active];
> +
> + if (next && next->funcs->mode_set)
> + next->funcs->mode_set(next, mode, adjusted_mode);
> +}
> +
> +/**
This isn't kerneldoc, the comment should start with /*. Same comment
below.
> + * Since this driver _reacts_ to mux changes, we need to make sure all
> + * downstream bridges are pre-enabled.
I'm afraid the problem scope seems bigger than I initially anticipated
:-( We're in the hack territory here, and I think we need to search for
a proper solution. We need to start with a detailed description of the
hardware and the use cases.
> + */
> +static void gpio_display_mux_pre_enable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->pre_enable)
> + next->funcs->pre_enable(next);
> + }
> +}
> +
> +static void gpio_display_mux_post_disable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->post_disable)
> + next->funcs->post_disable(next);
> + }
> +}
> +
> +/**
> + * In an ideal mux driver, only the currently selected bridge should be enabled.
> + * For the sake of simplicity, we just just enable/disable all downstream
> + * bridges at the same time.
> + */
> +static void gpio_display_mux_enable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->enable)
> + next->funcs->enable(next);
> + }
> +}
> +
> +static void gpio_display_mux_disable(struct drm_bridge *bridge)
> +{
> + struct gpio_display_mux *gpio_display_mux =
> + bridge_to_gpio_display_mux(bridge);
> + struct drm_bridge *next;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {
> + next = gpio_display_mux->next[i];
> + if (next && next->funcs->disable)
> + next->funcs->disable(next);
> + }
> +}
> +
> +static const struct drm_bridge_funcs gpio_display_mux_bridge_funcs = {
> + .attach = gpio_display_mux_attach,
> + .mode_fixup = gpio_display_mux_mode_fixup,
> + .disable = gpio_display_mux_disable,
> + .post_disable = gpio_display_mux_post_disable,
> + .mode_set = gpio_display_mux_mode_set,
> + .pre_enable = gpio_display_mux_pre_enable,
> + .enable = gpio_display_mux_enable,
> +};
> +
> +static int gpio_display_mux_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct gpio_display_mux *gpio_display_mux;
> + struct device_node *port, *ep, *remote;
> + int ret;
> + u32 reg;
> +
> + gpio_display_mux = devm_kzalloc(dev, sizeof(*gpio_display_mux),
> + GFP_KERNEL);
> + if (!gpio_display_mux)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, gpio_display_mux);
> + gpio_display_mux->dev = &pdev->dev;
> +
> + gpio_display_mux->bridge.of_node = dev->of_node;
> +
> + gpio_display_mux->gpiod_detect =
> + devm_gpiod_get(dev, "detect", GPIOD_IN);
> + if (IS_ERR(gpio_display_mux->gpiod_detect))
> + return PTR_ERR(gpio_display_mux->gpiod_detect);
> +
> + gpio_display_mux->detect_irq =
> + gpiod_to_irq(gpio_display_mux->gpiod_detect);
> + if (gpio_display_mux->detect_irq < 0) {
> + dev_err(dev, "Failed to get output irq %d\n",
> + gpio_display_mux->detect_irq);
> + return -ENODEV;
> + }
> +
> + port = of_graph_get_port_by_id(dev->of_node, 1);
> + if (!port) {
> + dev_err(dev, "Missing output port node\n");
> + return -EINVAL;
> + }
> +
> + for_each_child_of_node(port, ep) {
> + if (!ep->name || (of_node_cmp(ep->name, "endpoint") != 0)) {
> + of_node_put(ep);
> + continue;
> + }
> +
> + if (of_property_read_u32(ep, "reg", ®) < 0 ||
> + reg >= ARRAY_SIZE(gpio_display_mux->next)) {
> + dev_err(dev,
> + "Missing/invalid reg property for endpoint %s\n",
> + ep->full_name);
> + of_node_put(ep);
> + of_node_put(port);
> + return -EINVAL;
> + }
> +
> + remote = of_graph_get_remote_port_parent(ep);
> + if (!remote) {
> + dev_err(dev,
> + "Missing connector/bridge node for endpoint %s\n",
> + ep->full_name);
> + of_node_put(ep);
> + of_node_put(port);
> + return -EINVAL;
> + }
> + of_node_put(ep);
> +
> + if (of_device_is_compatible(remote, "hdmi-connector")) {
> + of_node_put(remote);
> + continue;
> + }
This special case makes me think that something is wrong. I believe the
connector driver from
https://patchwork.freedesktop.org/patch/344477/?series=63328&rev=59
could help.
> +
> + gpio_display_mux->next[reg] = of_drm_find_bridge(remote);
What if the connected device is a panel and not a bridge ?
> + if (!gpio_display_mux->next[reg]) {
> + dev_err(dev, "Waiting for external bridge %s\n",
> + remote->name);
> + of_node_put(remote);
> + of_node_put(port);
> + return -EPROBE_DEFER;
> + }
> +
> + of_node_put(remote);
> + }
> + of_node_put(port);
> +
> + gpio_display_mux->bridge.funcs = &gpio_display_mux_bridge_funcs;
> + drm_bridge_add(&gpio_display_mux->bridge);
> +
> + ret = devm_request_threaded_irq(dev, gpio_display_mux->detect_irq,
> + NULL,
> + gpio_display_mux_det_threaded_handler,
> + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
> + IRQF_ONESHOT,
> + "gpio-display-mux-det", gpio_display_mux);
> + if (ret) {
> + dev_err(dev, "Failed to request MUX_DET threaded irq\n");
> + goto err_bridge_remove;
> + }
> +
> + return 0;
> +
> +err_bridge_remove:
> + drm_bridge_remove(&gpio_display_mux->bridge);
> +
> + return ret;
> +}
> +
> +static int gpio_display_mux_remove(struct platform_device *pdev)
> +{
> + struct gpio_display_mux *gpio_display_mux = platform_get_drvdata(pdev);
> +
> + drm_bridge_remove(&gpio_display_mux->bridge);
If the GPIO IRQ is triggered here you'll have trouble. You need to
disable the IRQ, or free it, before removing the bridge.
> +
> + return 0;
> +}
> +
> +static const struct of_device_id gpio_display_mux_match[] = {
> + { .compatible = "gpio-display-mux", },
> + {},
> +};
> +
> +struct platform_driver gpio_display_mux_driver = {
> + .probe = gpio_display_mux_probe,
> + .remove = gpio_display_mux_remove,
> + .driver = {
> + .name = "gpio-display-mux",
> + .of_match_table = gpio_display_mux_match,
> + },
> +};
> +
> +module_platform_driver(gpio_display_mux_driver);
> +
> +MODULE_DESCRIPTION("GPIO-controlled display mux");
> +MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
> +MODULE_LICENSE("GPL v2");
--
Regards,
Laurent Pinchart
Hi Hsin-Yi and Nicolas,
Thank you for the patch.
On Wed, Dec 11, 2019 at 02:19:09PM +0800, Hsin-Yi Wang wrote:
> From: Nicolas Boichat <[email protected]>
>
> ANX7688 is a HDMI to DP converter (as well as USB-C port controller),
> that has an internal microcontroller.
>
> The only reason a Linux kernel driver is necessary is to reject
> resolutions that require more bandwidth than what is available on
> the DP side. DP bandwidth and lane count are reported by the bridge
> via 2 registers on I2C.
How about power, doesn't this chip have power supplies that potentially
need to be controlled ?
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
> ---
> drivers/gpu/drm/bridge/Kconfig | 9 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/analogix-anx7688.c | 202 ++++++++++++++++++++++
> 3 files changed, 212 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 34362976cd6f..1f3fc6bec842 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -16,6 +16,15 @@ config DRM_PANEL_BRIDGE
> menu "Display Interface Bridges"
> depends on DRM && DRM_BRIDGE
>
> +config DRM_ANALOGIX_ANX7688
> + tristate "Analogix ANX7688 bridge"
> + select DRM_KMS_HELPER
> + select REGMAP_I2C
> + ---help---
> + ANX7688 is a transmitter to support DisplayPort over USB-C for
> + smartphone and tablets.
> + This driver only supports the HDMI to DP component of the chip.
> +
> config DRM_ANALOGIX_ANX78XX
> tristate "Analogix ANX78XX bridge"
> select DRM_KMS_HELPER
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 4934fcf5a6f8..7a1e0ec032e6 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
> obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
> obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c
> new file mode 100644
> index 000000000000..baaed48d6201
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/analogix-anx7688.c
> @@ -0,0 +1,202 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ANX7688 HDMI->DP bridge driver
> + *
> + * Copyright 2016 Google LLC
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <drm/drm_bridge.h>
> +
> +/* Register addresses */
> +#define VENDOR_ID_REG 0x00
> +#define DEVICE_ID_REG 0x02
> +
> +#define FW_VERSION_REG 0x80
> +
> +#define DP_BANDWIDTH_REG 0x85
> +#define DP_LANE_COUNT_REG 0x86
Are these registers defined by the ANX7688 hardware, or by the firmware
running on the chip (and, I assume, developed by Google) ?
> +
> +#define VENDOR_ID 0x1f29
> +#define DEVICE_ID 0x7688
> +
> +/* First supported firmware version (0.85) */
> +#define MINIMUM_FW_VERSION 0x0085
> +
> +struct anx7688 {
> + struct drm_bridge bridge;
> + struct i2c_client *client;
> + struct regmap *regmap;
> +
> + bool filter;
> +};
> +
> +static inline struct anx7688 *bridge_to_anx7688(struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct anx7688, bridge);
> +}
> +
> +static bool anx7688_bridge_mode_fixup(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct anx7688 *anx7688 = bridge_to_anx7688(bridge);
> + u8 regs[2];
> + u8 dpbw, lanecount;
> + int totalbw, requiredbw;
> + int ret;
> +
> + if (!anx7688->filter)
> + return true;
> +
> + /* Read both regs 0x85 (bandwidth) and 0x86 (lane count). */
> + ret = regmap_bulk_read(anx7688->regmap, DP_BANDWIDTH_REG, regs, 2);
> + if (ret < 0) {
> + dev_err(&anx7688->client->dev,
> + "Failed to read bandwidth/lane count\n");
> + return false;
> + }
> + dpbw = regs[0];
> + lanecount = regs[1];
> +
> + /* Maximum 0x19 bandwidth (6.75 Gbps Turbo mode), 2 lanes */
> + if (dpbw > 0x19 || lanecount > 2) {
> + dev_err(&anx7688->client->dev,
> + "Invalid bandwidth/lane count (%02x/%d)\n",
> + dpbw, lanecount);
> + return false;
> + }
> +
> + /* Compute available bandwidth (kHz) */
> + totalbw = dpbw * lanecount * 270000 * 8 / 10;
> +
> + /* Required bandwidth (8 bpc, kHz) */
> + requiredbw = mode->clock * 8 * 3;
> +
> + dev_dbg(&anx7688->client->dev,
> + "DP bandwidth: %d kHz (%02x/%d); mode requires %d Khz\n",
> + totalbw, dpbw, lanecount, requiredbw);
> +
> + if (totalbw == 0) {
> + dev_warn(&anx7688->client->dev,
> + "Bandwidth/lane count are 0, not rejecting modes\n");
> + return true;
> + }
> +
> + return totalbw >= requiredbw;
> +}
> +
> +static const struct drm_bridge_funcs anx7688_bridge_funcs = {
> + .mode_fixup = anx7688_bridge_mode_fixup,
> +};
> +
> +static const struct regmap_config anx7688_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +};
> +
> +static int anx7688_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct anx7688 *anx7688;
> + struct device *dev = &client->dev;
> + int ret;
> + u8 buffer[4];
> + u16 vendor, device, fwversion;
> +
> + anx7688 = devm_kzalloc(dev, sizeof(*anx7688), GFP_KERNEL);
> + if (!anx7688)
> + return -ENOMEM;
> +
> +#if IS_ENABLED(CONFIG_OF)
> + anx7688->bridge.of_node = client->dev.of_node;
> +#endif
> +
> + anx7688->client = client;
> + i2c_set_clientdata(client, anx7688);
> +
> + anx7688->regmap =
> + devm_regmap_init_i2c(client, &anx7688_regmap_config);
> +
> + /* Read both vendor and device id (4 bytes). */
> + ret = regmap_bulk_read(anx7688->regmap, VENDOR_ID_REG, buffer, 4);
> + if (ret) {
> + dev_err(dev, "Failed to read chip vendor/device id\n");
> + return ret;
> + }
> +
> + vendor = (u16)buffer[1] << 8 | buffer[0];
> + device = (u16)buffer[3] << 8 | buffer[2];
> + if (vendor != VENDOR_ID || device != DEVICE_ID) {
> + dev_err(dev, "Invalid vendor/device id %04x/%04x\n",
> + vendor, device);
> + return -ENODEV;
> + }
> +
> + ret = regmap_bulk_read(anx7688->regmap, FW_VERSION_REG, buffer, 2);
> + if (ret) {
> + dev_err(&client->dev, "Failed to read firmware version\n");
> + return ret;
> + }
> +
> + fwversion = (u16)buffer[0] << 8 | buffer[1];
> + dev_info(dev, "ANX7688 firwmare version %02x.%02x\n",
> + buffer[0], buffer[1]);
> +
> + /* FW version >= 0.85 supports bandwidth/lane count registers */
> + if (fwversion >= MINIMUM_FW_VERSION) {
> + anx7688->filter = true;
> + } else {
> + /* Warn, but not fail, for backwards compatibility. */
> + dev_warn(dev,
> + "Old ANX7688 FW version (%02x.%02x), not filtering\n",
> + buffer[0], buffer[1]);
> + }
> +
> + anx7688->bridge.funcs = &anx7688_bridge_funcs;
> + drm_bridge_add(&anx7688->bridge);
> +
> + return 0;
> +}
> +
> +static int anx7688_i2c_remove(struct i2c_client *client)
> +{
> + struct anx7688 *anx7688 = i2c_get_clientdata(client);
> +
> + drm_bridge_remove(&anx7688->bridge);
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id anx7688_id[] = {
> + { "anx7688", 0 },
> + { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, anx7688_id);
> +
> +#if IS_ENABLED(CONFIG_OF)
> +static const struct of_device_id anx7688_match_table[] = {
> + { .compatible = "analogix,anx7688", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, anx7688_match_table);
> +#endif
> +
> +static struct i2c_driver anx7688_driver = {
> + .driver = {
> + .name = "anx7688",
> + .of_match_table = of_match_ptr(anx7688_match_table),
> + },
> + .probe = anx7688_i2c_probe,
> + .remove = anx7688_i2c_remove,
> + .id_table = anx7688_id,
> +};
> +
> +module_i2c_driver(anx7688_driver);
> +
> +MODULE_DESCRIPTION("ANX7688 SlimPort Transmitter driver");
> +MODULE_AUTHOR("Nicolas Boichat <[email protected]>");
> +MODULE_LICENSE("GPL v2");
--
Regards,
Laurent Pinchart
On Wed, Dec 11, 2019 at 02:19:08PM +0800, Hsin-Yi Wang wrote:
> From: Nicolas Boichat <[email protected]>
>
> Add support for analogix,anx7688
>
> Signed-off-by: Nicolas Boichat <[email protected]>
> Signed-off-by: Hsin-Yi Wang <[email protected]>
> ---
> Change from RFC to v1:
> - txt to yaml
> ---
> .../bindings/display/bridge/anx7688.yaml | 60 +++++++++++++++++++
> 1 file changed, 60 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> new file mode 100644
> index 000000000000..cf79f7cf8fdf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> @@ -0,0 +1,60 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/anx7688.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analogix ANX7688 SlimPort (Single-Chip Transmitter for DP over USB-C)
> +
> +maintainers:
> + - Nicolas Boichat <[email protected]>
> +
> +description: |
> + The ANX7688 is a single-chip mobile transmitter to support 4K 60 frames per
> + second (4096x2160p60) or FHD 120 frames per second (1920x1080p120) video
> + resolution from a smartphone or tablet with full function USB-C.
> +
> + This binding only describes the HDMI to DP display bridge.
> +
> +properties:
> + compatible:
> + const: analogix,anx7688
> +
> + reg:
> + maxItems: 1
> + description: I2C address of the device
> +
> + ports:
> + type: object
> +
> + properties:
> + port@0:
> + type: object
> + description: |
> + Video port for HDMI input
> +
> + port@1:
> + type: object
> + description: |
> + Video port for eDP output
> +
> + required:
> + - port@0
Sometimes you have no output?
> +
> +required:
> + - compatible
> + - reg
> + - ports
The example will have errors because it is missing 'ports'. Run 'make
dt_binding_check'.
Add:
additionalProperties: false
> +
> +examples:
> + - |
> + anx7688: anx7688@2c {
> + compatible = "analogix,anx7688";
> + reg = <0x2c>;
> +
> + port {
> + anx7688_in: endpoint {
> + remote-endpoint = <&hdmi0_out>;
> + };
> + };
> + };
> --
> 2.24.0.525.g8f36a354ae-goog
>
On Mon, Dec 16, 2019 at 03:16:23PM +0800, Hsin-Yi Wang wrote:
> On Sat, Dec 14, 2019 at 5:29 AM Rob Herring <[email protected]> wrote:
> >
> > On Wed, Dec 11, 2019 at 12:19 AM Hsin-Yi Wang <[email protected]> wrote:
> > >
> > > From: Nicolas Boichat <[email protected]>
> > >
> > > Add bindings for Generic GPIO mux driver.
> > >
> > > Signed-off-by: Nicolas Boichat <[email protected]>
> > > Signed-off-by: Hsin-Yi Wang <[email protected]>
> > > ---
> > > Change from RFC to v1:
> > > - txt to yaml
> > > ---
> > > .../bindings/display/bridge/gpio-mux.yaml | 89 +++++++++++++++++++
> > > 1 file changed, 89 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > > new file mode 100644
> > > index 000000000000..cef098749066
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > > @@ -0,0 +1,89 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/bridge/gpio-mux.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Generic display mux (1 input, 2 outputs)
> >
> > What makes it generic? Doesn't the mux chip have power supply,
> > possibly a reset line or not, etc.? What about a mux where the GPIO
> > controls the mux?
> >
> > Generally, we avoid 'generic' bindings because h/w is rarely generic.
> > You can have a generic driver which works on multiple devices.
> >
> Then how about making it mt8173-oak-gpio-mux? Since this is currently
> only used in this board.
Isn't there an underlying part# you can use? Or if you can point me to
multiple chips implementing the same thing, then maybe a generic binding
is fine.
Rob
On Fri, Dec 20, 2019 at 4:45 AM Rob Herring <[email protected]> wrote:
>
> On Wed, Dec 11, 2019 at 02:19:08PM +0800, Hsin-Yi Wang wrote:
> > From: Nicolas Boichat <[email protected]>
> >
> > Add support for analogix,anx7688
> >
> > Signed-off-by: Nicolas Boichat <[email protected]>
> > Signed-off-by: Hsin-Yi Wang <[email protected]>
> > ---
> > Change from RFC to v1:
> > - txt to yaml
> > ---
> > .../bindings/display/bridge/anx7688.yaml | 60 +++++++++++++++++++
> > 1 file changed, 60 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > new file mode 100644
> > index 000000000000..cf79f7cf8fdf
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > @@ -0,0 +1,60 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/display/bridge/anx7688.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Analogix ANX7688 SlimPort (Single-Chip Transmitter for DP over USB-C)
> > +
> > +maintainers:
> > + - Nicolas Boichat <[email protected]>
> > +
> > +description: |
> > + The ANX7688 is a single-chip mobile transmitter to support 4K 60 frames per
> > + second (4096x2160p60) or FHD 120 frames per second (1920x1080p120) video
> > + resolution from a smartphone or tablet with full function USB-C.
> > +
> > + This binding only describes the HDMI to DP display bridge.
> > +
> > +properties:
> > + compatible:
> > + const: analogix,anx7688
> > +
> > + reg:
> > + maxItems: 1
> > + description: I2C address of the device
> > +
> > + ports:
> > + type: object
> > +
> > + properties:
> > + port@0:
> > + type: object
> > + description: |
> > + Video port for HDMI input
> > +
> > + port@1:
> > + type: object
> > + description: |
> > + Video port for eDP output
> > +
> > + required:
> > + - port@0
>
> Sometimes you have no output?
Yes, only input is required.
>
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - ports
>
> The example will have errors because it is missing 'ports'. Run 'make
> dt_binding_check'.
>
> Add:
>
> additionalProperties: false
>
Ack, will fix this. Thanks
> > +
> > +examples:
> > + - |
> > + anx7688: anx7688@2c {
> > + compatible = "analogix,anx7688";
> > + reg = <0x2c>;
> > +
> > + port {
> > + anx7688_in: endpoint {
> > + remote-endpoint = <&hdmi0_out>;
> > + };
> > + };
> > + };
> > --
> > 2.24.0.525.g8f36a354ae-goog
> >
Hi Hsin-Yi,
On Fri, Dec 20, 2019 at 11:20:13AM +0800, Hsin-Yi Wang wrote:
> On Fri, Dec 20, 2019 at 4:45 AM Rob Herring wrote:
> > On Wed, Dec 11, 2019 at 02:19:08PM +0800, Hsin-Yi Wang wrote:
> > > From: Nicolas Boichat <[email protected]>
> > >
> > > Add support for analogix,anx7688
> > >
> > > Signed-off-by: Nicolas Boichat <[email protected]>
> > > Signed-off-by: Hsin-Yi Wang <[email protected]>
> > > ---
> > > Change from RFC to v1:
> > > - txt to yaml
> > > ---
> > > .../bindings/display/bridge/anx7688.yaml | 60 +++++++++++++++++++
> > > 1 file changed, 60 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > > new file mode 100644
> > > index 000000000000..cf79f7cf8fdf
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > > @@ -0,0 +1,60 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/bridge/anx7688.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Analogix ANX7688 SlimPort (Single-Chip Transmitter for DP over USB-C)
> > > +
> > > +maintainers:
> > > + - Nicolas Boichat <[email protected]>
> > > +
> > > +description: |
> > > + The ANX7688 is a single-chip mobile transmitter to support 4K 60 frames per
> > > + second (4096x2160p60) or FHD 120 frames per second (1920x1080p120) video
> > > + resolution from a smartphone or tablet with full function USB-C.
> > > +
> > > + This binding only describes the HDMI to DP display bridge.
> > > +
> > > +properties:
> > > + compatible:
> > > + const: analogix,anx7688
> > > +
> > > + reg:
> > > + maxItems: 1
> > > + description: I2C address of the device
> > > +
> > > + ports:
> > > + type: object
> > > +
> > > + properties:
> > > + port@0:
> > > + type: object
> > > + description: |
> > > + Video port for HDMI input
> > > +
> > > + port@1:
> > > + type: object
> > > + description: |
> > > + Video port for eDP output
> > > +
> > > + required:
> > > + - port@0
> >
> > Sometimes you have no output?
>
> Yes, only input is required.
But what happens in that case ? What's the use of a bridge with a
non-connected output ? :-)
> > > +
> > > +required:
> > > + - compatible
> > > + - reg
> > > + - ports
> >
> > The example will have errors because it is missing 'ports'. Run 'make
> > dt_binding_check'.
> >
> > Add:
> >
> > additionalProperties: false
> >
>
> Ack, will fix this. Thanks
>
> > > +
> > > +examples:
> > > + - |
> > > + anx7688: anx7688@2c {
> > > + compatible = "analogix,anx7688";
> > > + reg = <0x2c>;
> > > +
> > > + port {
> > > + anx7688_in: endpoint {
> > > + remote-endpoint = <&hdmi0_out>;
> > > + };
> > > + };
> > > + };
--
Regards,
Laurent Pinchart
On Fri, Dec 20, 2019 at 11:22 AM Laurent Pinchart
<[email protected]> wrote:
>
> Hi Hsin-Yi,
>
> On Fri, Dec 20, 2019 at 11:20:13AM +0800, Hsin-Yi Wang wrote:
> > On Fri, Dec 20, 2019 at 4:45 AM Rob Herring wrote:
> > > On Wed, Dec 11, 2019 at 02:19:08PM +0800, Hsin-Yi Wang wrote:
> > > > From: Nicolas Boichat <[email protected]>
> > > >
> > > > Add support for analogix,anx7688
> > > >
> > > > Signed-off-by: Nicolas Boichat <[email protected]>
> > > > Signed-off-by: Hsin-Yi Wang <[email protected]>
> > > > ---
> > > > Change from RFC to v1:
> > > > - txt to yaml
> > > > ---
> > > > .../bindings/display/bridge/anx7688.yaml | 60 +++++++++++++++++++
> > > > 1 file changed, 60 insertions(+)
> > > > create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.yaml b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > > > new file mode 100644
> > > > index 000000000000..cf79f7cf8fdf
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/display/bridge/anx7688.yaml
> > > > @@ -0,0 +1,60 @@
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/display/bridge/anx7688.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Analogix ANX7688 SlimPort (Single-Chip Transmitter for DP over USB-C)
> > > > +
> > > > +maintainers:
> > > > + - Nicolas Boichat <[email protected]>
> > > > +
> > > > +description: |
> > > > + The ANX7688 is a single-chip mobile transmitter to support 4K 60 frames per
> > > > + second (4096x2160p60) or FHD 120 frames per second (1920x1080p120) video
> > > > + resolution from a smartphone or tablet with full function USB-C.
> > > > +
> > > > + This binding only describes the HDMI to DP display bridge.
> > > > +
> > > > +properties:
> > > > + compatible:
> > > > + const: analogix,anx7688
> > > > +
> > > > + reg:
> > > > + maxItems: 1
> > > > + description: I2C address of the device
> > > > +
> > > > + ports:
> > > > + type: object
> > > > +
> > > > + properties:
> > > > + port@0:
> > > > + type: object
> > > > + description: |
> > > > + Video port for HDMI input
> > > > +
> > > > + port@1:
> > > > + type: object
> > > > + description: |
> > > > + Video port for eDP output
> > > > +
> > > > + required:
> > > > + - port@0
> > >
> > > Sometimes you have no output?
> >
> > Yes, only input is required.
>
> But what happens in that case ? What's the use of a bridge with a
> non-connected output ? :-)
>
There's output connected, but doesn't need a driver. For example, in
our use case it's connected to a usb-c connector. We don't need to
state it in dts.
I also checked https://elixir.bootlin.com/linux/v5.5-rc2/source/Documentation/devicetree/bindings/display/bridge/anx6345.yaml
and thought that output could be optional. Also
https://elixir.bootlin.com/linux/v5.5-rc2/source/arch/arm64/boot/dts/allwinner/sun50i-a64-teres-i.dts#L116
Or maybe we can add output in example as anx6345?
> > > > +
> > > > +required:
> > > > + - compatible
> > > > + - reg
> > > > + - ports
> > >
> > > The example will have errors because it is missing 'ports'. Run 'make
> > > dt_binding_check'.
> > >
> > > Add:
> > >
> > > additionalProperties: false
> > >
> >
> > Ack, will fix this. Thanks
> >
> > > > +
> > > > +examples:
> > > > + - |
> > > > + anx7688: anx7688@2c {
> > > > + compatible = "analogix,anx7688";
> > > > + reg = <0x2c>;
> > > > +
> > > > + port {
> > > > + anx7688_in: endpoint {
> > > > + remote-endpoint = <&hdmi0_out>;
> > > > + };
> > > > + };
> > > > + };
>
> --
> Regards,
>
> Laurent Pinchart
On Fri, Dec 20, 2019 at 4:48 AM Rob Herring <[email protected]> wrote:
>
> On Mon, Dec 16, 2019 at 03:16:23PM +0800, Hsin-Yi Wang wrote:
> > On Sat, Dec 14, 2019 at 5:29 AM Rob Herring <[email protected]> wrote:
> > >
> > > On Wed, Dec 11, 2019 at 12:19 AM Hsin-Yi Wang <[email protected]> wrote:
> > > >
> > > > From: Nicolas Boichat <[email protected]>
> > > >
> > > > Add bindings for Generic GPIO mux driver.
> > > >
> > > > Signed-off-by: Nicolas Boichat <[email protected]>
> > > > Signed-off-by: Hsin-Yi Wang <[email protected]>
> > > > ---
> > > > Change from RFC to v1:
> > > > - txt to yaml
> > > > ---
> > > > .../bindings/display/bridge/gpio-mux.yaml | 89 +++++++++++++++++++
> > > > 1 file changed, 89 insertions(+)
> > > > create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > > > new file mode 100644
> > > > index 000000000000..cef098749066
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
> > > > @@ -0,0 +1,89 @@
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/display/bridge/gpio-mux.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Generic display mux (1 input, 2 outputs)
> > >
> > > What makes it generic? Doesn't the mux chip have power supply,
> > > possibly a reset line or not, etc.? What about a mux where the GPIO
> > > controls the mux?
> > >
> > > Generally, we avoid 'generic' bindings because h/w is rarely generic.
> > > You can have a generic driver which works on multiple devices.
> > >
> > Then how about making it mt8173-oak-gpio-mux? Since this is currently
> > only used in this board.
>
> Isn't there an underlying part# you can use? Or if you can point me to
> multiple chips implementing the same thing, then maybe a generic binding
> is fine.
There are some similar chips, for example:
https://www.paradetech.com/zh-hant/%E7%94%A2%E5%93%81%E4%BB%8B%E7%B4%B9/ps8223-3-0gbps-hdmi-12-demultiplexer/
and http://www.ti.com/lit/ds/symlink/ts3dv642.pdf
If they are used in a similar way
(https://lore.kernel.org/lkml/CANMq1KDDEzPWhByEtn-EjNcg+ofVT2MW-hOXANGooYFOYJ35VA@mail.gmail.com/),
they would need such driver. But currently we only know that mt8173
oak board have this use case.
>
> Rob