This patch series introduces LVDS controller support for the SAM9X75 SoC. The
LVDS controller is designed to work with Microchip's sam9x7 series
System-on-Chip (SoC) devices, providing Low Voltage Differential Signaling
capabilities.
Patch series Changelog:
- Include configs: at91: Enable LVDS serializer
- include all necessary To/Cc entries.
The Individual Changelogs are available on the respective patches.
Dharma Balasubiramani (4):
dt-bindings: display: bridge: add sam9x75-lvds binding
drm/bridge: add lvds controller support for sam9x7
MAINTAINERS: add SAM9X7 SoC's LVDS controller
ARM: configs: at91: Enable LVDS serializer support
.../bridge/microchip,sam9x75-lvds.yaml | 55 +++++
MAINTAINERS | 8 +
arch/arm/configs/at91_dt_defconfig | 1 +
drivers/gpu/drm/bridge/Kconfig | 7 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++
6 files changed, 300 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
--
2.25.1
Add a new LVDS controller driver for sam9x7 which does the following:
- Prepares and enables the LVDS Peripheral clock
- Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
to the global bridge list.
- Identifies its output endpoint as panel and adds it to the encoder
display pipeline
- Enables the LVDS serializer
Signed-off-by: Manikandan Muralidharan <[email protected]>
Signed-off-by: Dharma Balasubiramani <[email protected]>
---
Changelog
v5 -> v6
- No Changes.
v4 -> v5
- Drop the unused variable 'format'.
- Use DRM wrapper for dev_err() to maintain uniformity.
- return -ENODEV instead of -EINVAL to maintain consistency with other DRM
bridge drivers.
v3 -> v4
- No changes.
v2 ->v3
- Correct Typo error "serializer".
- Consolidate get() and prepare() functions and use devm_clk_get_prepared().
- Remove unused variable 'ret' in probe().
- Use devm_pm_runtime_enable() and drop the mchp_lvds_remove().
v1 -> v2
- Drop 'res' variable and combine two lines into one.
- Handle deferred probe properly, use dev_err_probe().
- Don't print anything on deferred probe. Dropped print.
- Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
- symbol 'mchp_lvds_driver' was not declared. It should be static.
---
drivers/gpu/drm/bridge/Kconfig | 7 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++++++++
3 files changed, 236 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index efd996f6c138..889098e2d65f 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -190,6 +190,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
to DP++. This is used with the i.MX6 imx-ldb
driver. You are likely to say N here.
+config DRM_MICROCHIP_LVDS_SERIALIZER
+ tristate "Microchip LVDS serializer support"
+ depends on OF
+ depends on DRM_ATMEL_HLCDC
+ help
+ Support for Microchip's LVDS serializer.
+
config DRM_NWL_MIPI_DSI
tristate "Northwest Logic MIPI DSI Host controller"
depends on DRM
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 017b5832733b..7df87b582dca 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
+obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
new file mode 100644
index 000000000000..149704f498a6
--- /dev/null
+++ b/drivers/gpu/drm/bridge/microchip-lvds.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Manikandan Muralidharan <[email protected]>
+ * Author: Dharma Balasubiramani <[email protected]>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_graph.h>
+#include <linux/pinctrl/devinfo.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#define LVDS_POLL_TIMEOUT_MS 1000
+
+/* LVDSC register offsets */
+#define LVDSC_CR 0x00
+#define LVDSC_CFGR 0x04
+#define LVDSC_SR 0x0C
+#define LVDSC_WPMR 0xE4
+
+/* Bitfields in LVDSC_CR (Control Register) */
+#define LVDSC_CR_SER_EN BIT(0)
+
+/* Bitfields in LVDSC_CFGR (Configuration Register) */
+#define LVDSC_CFGR_PIXSIZE_24BITS 0
+#define LVDSC_CFGR_DEN_POL_HIGH 0
+#define LVDSC_CFGR_DC_UNBALANCED 0
+#define LVDSC_CFGR_MAPPING_JEIDA BIT(6)
+
+/*Bitfields in LVDSC_SR */
+#define LVDSC_SR_CS BIT(0)
+
+/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
+#define LVDSC_WPMR_WPKEY_MASK GENMASK(31, 8)
+#define LVDSC_WPMR_WPKEY_PSSWD 0x4C5644
+
+struct mchp_lvds {
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *pclk;
+ struct drm_panel *panel;
+ struct drm_bridge bridge;
+ struct drm_bridge *panel_bridge;
+};
+
+static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct mchp_lvds, bridge);
+}
+
+static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
+{
+ return readl_relaxed(lvds->regs + offset);
+}
+
+static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
+{
+ writel_relaxed(val, lvds->regs + offset);
+}
+
+static void lvds_serialiser_on(struct mchp_lvds *lvds)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
+
+ /* The LVDSC registers can only be written if WPEN is cleared */
+ lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
+ LVDSC_WPMR_WPKEY_MASK));
+
+ /* Wait for the status of configuration registers to be changed */
+ while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
+ if (time_after(jiffies, timeout)) {
+ DRM_DEV_ERROR(lvds->dev, "%s: timeout error\n",
+ __func__);
+ return;
+ }
+ usleep_range(1000, 2000);
+ }
+
+ /* Configure the LVDSC */
+ lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
+ LVDSC_CFGR_DC_UNBALANCED |
+ LVDSC_CFGR_DEN_POL_HIGH |
+ LVDSC_CFGR_PIXSIZE_24BITS));
+
+ /* Enable the LVDS serializer */
+ lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
+}
+
+static int mchp_lvds_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+
+ bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
+
+ return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
+ bridge, flags);
+}
+
+static void mchp_lvds_enable(struct drm_bridge *bridge)
+{
+ struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+ int ret;
+
+ ret = clk_enable(lvds->pclk);
+ if (ret < 0) {
+ DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
+ return;
+ }
+
+ ret = pm_runtime_get_sync(lvds->dev);
+ if (ret < 0) {
+ DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
+ clk_disable(lvds->pclk);
+ return;
+ }
+
+ lvds_serialiser_on(lvds);
+}
+
+static void mchp_lvds_disable(struct drm_bridge *bridge)
+{
+ struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+
+ pm_runtime_put(lvds->dev);
+ clk_disable(lvds->pclk);
+}
+
+static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
+ .attach = mchp_lvds_attach,
+ .enable = mchp_lvds_enable,
+ .disable = mchp_lvds_disable,
+};
+
+static int mchp_lvds_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mchp_lvds *lvds;
+ struct device_node *port;
+
+ if (!dev->of_node)
+ return -ENODEV;
+
+ lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
+ if (!lvds)
+ return -ENOMEM;
+
+ lvds->dev = dev;
+
+ lvds->regs = devm_ioremap_resource(lvds->dev,
+ platform_get_resource(pdev, IORESOURCE_MEM, 0));
+ if (IS_ERR(lvds->regs))
+ return PTR_ERR(lvds->regs);
+
+ lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
+ if (IS_ERR(lvds->pclk))
+ return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
+ "could not get pclk_lvds prepared\n");
+
+ port = of_graph_get_remote_node(dev->of_node, 1, 0);
+ if (!port) {
+ DRM_DEV_ERROR(dev,
+ "can't find port point, please init lvds panel port!\n");
+ return -ENODEV;
+ }
+
+ lvds->panel = of_drm_find_panel(port);
+ of_node_put(port);
+
+ if (IS_ERR(lvds->panel))
+ return -EPROBE_DEFER;
+
+ lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
+
+ if (IS_ERR(lvds->panel_bridge))
+ return PTR_ERR(lvds->panel_bridge);
+
+ lvds->bridge.of_node = dev->of_node;
+ lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
+ lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
+
+ dev_set_drvdata(dev, lvds);
+ devm_pm_runtime_enable(dev);
+
+ drm_bridge_add(&lvds->bridge);
+
+ return 0;
+}
+
+static const struct of_device_id mchp_lvds_dt_ids[] = {
+ {
+ .compatible = "microchip,sam9x75-lvds",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
+
+static struct platform_driver mchp_lvds_driver = {
+ .probe = mchp_lvds_probe,
+ .driver = {
+ .name = "microchip-lvds",
+ .of_match_table = mchp_lvds_dt_ids,
+ },
+};
+module_platform_driver(mchp_lvds_driver);
+
+MODULE_AUTHOR("Manikandan Muralidharan <[email protected]>");
+MODULE_AUTHOR("Dharma Balasubiramani <[email protected]>");
+MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
+MODULE_LICENSE("GPL");
--
2.25.1
Enable LVDS serializer support for display pipeline.
Signed-off-by: Dharma Balasubiramani <[email protected]>
Acked-by: Hari Prasath Gujulan Elango <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
---
Changelog
v4 -> v5
v3 -> v4
v2 -> v3
- No Changes.
---
arch/arm/configs/at91_dt_defconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
index 1d53aec4c836..6eabe2313c9a 100644
--- a/arch/arm/configs/at91_dt_defconfig
+++ b/arch/arm/configs/at91_dt_defconfig
@@ -143,6 +143,7 @@ CONFIG_VIDEO_OV2640=m
CONFIG_VIDEO_OV7740=m
CONFIG_DRM=y
CONFIG_DRM_ATMEL_HLCDC=y
+CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER=y
CONFIG_DRM_PANEL_SIMPLE=y
CONFIG_DRM_PANEL_EDP=y
CONFIG_FB_ATMEL=y
--
2.25.1
Add the newly added LVDS controller for the SAM9X7 SoC to the existing
MAINTAINERS entry.
Signed-off-by: Dharma Balasubiramani <[email protected]>
Reviewed-by: Neil Armstrong <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
---
Changelog
v5 -> v6
- Correct the file name sam9x7-lvds.yaml -> sam9x75-lvds.yaml.
v4 -> v5
v3 -> v4
- No changes.
v2 -> v3
- Move the entry before "MICROCHIP SAMA5D2-COMPATIBLE ADC DRIVER".
v1 -> v2
- No Changes.
---
MAINTAINERS | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index c23fda1aa1f0..e49347eac596 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14563,6 +14563,14 @@ S: Supported
F: Documentation/devicetree/bindings/pwm/atmel,at91sam-pwm.yaml
F: drivers/pwm/pwm-atmel.c
+MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
+M: Manikandan Muralidharan <[email protected]>
+M: Dharma Balasubiramani <[email protected]>
+L: [email protected]
+S: Supported
+F: Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
+F: drivers/gpu/drm/bridge/microchip-lvds.c
+
MICROCHIP SAMA5D2-COMPATIBLE ADC DRIVER
M: Eugen Hristev <[email protected]>
L: [email protected]
--
2.25.1
On Wed, Apr 17, 2024 at 08:11:35AM +0530, Dharma Balasubiramani wrote:
> Add a new LVDS controller driver for sam9x7 which does the following:
> - Prepares and enables the LVDS Peripheral clock
> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
> to the global bridge list.
> - Identifies its output endpoint as panel and adds it to the encoder
> display pipeline
> - Enables the LVDS serializer
>
> Signed-off-by: Manikandan Muralidharan <[email protected]>
> Signed-off-by: Dharma Balasubiramani <[email protected]>
> ---
> Changelog
> v5 -> v6
> - No Changes.
> v4 -> v5
> - Drop the unused variable 'format'.
> - Use DRM wrapper for dev_err() to maintain uniformity.
> - return -ENODEV instead of -EINVAL to maintain consistency with other DRM
> bridge drivers.
> v3 -> v4
> - No changes.
> v2 ->v3
> - Correct Typo error "serializer".
> - Consolidate get() and prepare() functions and use devm_clk_get_prepared().
> - Remove unused variable 'ret' in probe().
> - Use devm_pm_runtime_enable() and drop the mchp_lvds_remove().
> v1 -> v2
> - Drop 'res' variable and combine two lines into one.
> - Handle deferred probe properly, use dev_err_probe().
> - Don't print anything on deferred probe. Dropped print.
> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
> - symbol 'mchp_lvds_driver' was not declared. It should be static.
> ---
> drivers/gpu/drm/bridge/Kconfig | 7 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++++++++
> 3 files changed, 236 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index efd996f6c138..889098e2d65f 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -190,6 +190,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
> to DP++. This is used with the i.MX6 imx-ldb
> driver. You are likely to say N here.
>
> +config DRM_MICROCHIP_LVDS_SERIALIZER
> + tristate "Microchip LVDS serializer support"
> + depends on OF
> + depends on DRM_ATMEL_HLCDC
> + help
> + Support for Microchip's LVDS serializer.
> +
> config DRM_NWL_MIPI_DSI
> tristate "Northwest Logic MIPI DSI Host controller"
> depends on DRM
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 017b5832733b..7df87b582dca 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
> obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
> obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
> obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> +obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
> obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
> obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
> diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
> new file mode 100644
> index 000000000000..149704f498a6
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/microchip-lvds.c
> @@ -0,0 +1,228 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
> + *
> + * Author: Manikandan Muralidharan <[email protected]>
> + * Author: Dharma Balasubiramani <[email protected]>
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/delay.h>
> +#include <linux/jiffies.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_graph.h>
> +#include <linux/pinctrl/devinfo.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_simple_kms_helper.h>
> +
> +#define LVDS_POLL_TIMEOUT_MS 1000
> +
> +/* LVDSC register offsets */
> +#define LVDSC_CR 0x00
> +#define LVDSC_CFGR 0x04
> +#define LVDSC_SR 0x0C
> +#define LVDSC_WPMR 0xE4
> +
> +/* Bitfields in LVDSC_CR (Control Register) */
> +#define LVDSC_CR_SER_EN BIT(0)
> +
> +/* Bitfields in LVDSC_CFGR (Configuration Register) */
> +#define LVDSC_CFGR_PIXSIZE_24BITS 0
> +#define LVDSC_CFGR_DEN_POL_HIGH 0
> +#define LVDSC_CFGR_DC_UNBALANCED 0
> +#define LVDSC_CFGR_MAPPING_JEIDA BIT(6)
> +
> +/*Bitfields in LVDSC_SR */
> +#define LVDSC_SR_CS BIT(0)
> +
> +/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
> +#define LVDSC_WPMR_WPKEY_MASK GENMASK(31, 8)
> +#define LVDSC_WPMR_WPKEY_PSSWD 0x4C5644
> +
> +struct mchp_lvds {
> + struct device *dev;
> + void __iomem *regs;
> + struct clk *pclk;
> + struct drm_panel *panel;
> + struct drm_bridge bridge;
> + struct drm_bridge *panel_bridge;
> +};
> +
> +static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct mchp_lvds, bridge);
> +}
> +
> +static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
> +{
> + return readl_relaxed(lvds->regs + offset);
> +}
> +
> +static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
> +{
> + writel_relaxed(val, lvds->regs + offset);
> +}
> +
> +static void lvds_serialiser_on(struct mchp_lvds *lvds)
> +{
> + unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
> +
> + /* The LVDSC registers can only be written if WPEN is cleared */
> + lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
> + LVDSC_WPMR_WPKEY_MASK));
> +
> + /* Wait for the status of configuration registers to be changed */
> + while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
> + if (time_after(jiffies, timeout)) {
> + DRM_DEV_ERROR(lvds->dev, "%s: timeout error\n",
> + __func__);
> + return;
> + }
> + usleep_range(1000, 2000);
> + }
> +
> + /* Configure the LVDSC */
> + lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
> + LVDSC_CFGR_DC_UNBALANCED |
> + LVDSC_CFGR_DEN_POL_HIGH |
> + LVDSC_CFGR_PIXSIZE_24BITS));
> +
> + /* Enable the LVDS serializer */
> + lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
> +}
> +
> +static int mchp_lvds_attach(struct drm_bridge *bridge,
> + enum drm_bridge_attach_flags flags)
> +{
> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +
> + bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
Why do you need to touch encoder_type here? It's not your bridge's
responsibility.
> +
> + return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
> + bridge, flags);
> +}
> +
> +static void mchp_lvds_enable(struct drm_bridge *bridge)
> +{
> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> + int ret;
> +
> + ret = clk_enable(lvds->pclk);
> + if (ret < 0) {
> + DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
> + return;
> + }
> +
> + ret = pm_runtime_get_sync(lvds->dev);
> + if (ret < 0) {
> + DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
> + clk_disable(lvds->pclk);
This can result in unbalanced clk_disable(), if pm_runtime_get_sync()
fails. This function calls clk_disable(), but the framework has no way
to know that .enable() was not successful and calls .disable(), which
also calls clk_disable().
Please consider turning pclk into pm_clk so that its state is managed
automatically (or at least moving clk_enable/disable into pm_ops).
> + return;
> + }
> +
> + lvds_serialiser_on(lvds);
> +}
> +
> +static void mchp_lvds_disable(struct drm_bridge *bridge)
> +{
> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +
> + pm_runtime_put(lvds->dev);
> + clk_disable(lvds->pclk);
> +}
> +
> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
> + .attach = mchp_lvds_attach,
> + .enable = mchp_lvds_enable,
> + .disable = mchp_lvds_disable,
> +};
> +
> +static int mchp_lvds_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mchp_lvds *lvds;
> + struct device_node *port;
> +
> + if (!dev->of_node)
> + return -ENODEV;
> +
> + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
> + if (!lvds)
> + return -ENOMEM;
> +
> + lvds->dev = dev;
> +
> + lvds->regs = devm_ioremap_resource(lvds->dev,
> + platform_get_resource(pdev, IORESOURCE_MEM, 0));
> + if (IS_ERR(lvds->regs))
> + return PTR_ERR(lvds->regs);
> +
> + lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
Why do you need _prepared version?
> + if (IS_ERR(lvds->pclk))
> + return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
> + "could not get pclk_lvds prepared\n");
> +
> + port = of_graph_get_remote_node(dev->of_node, 1, 0);
> + if (!port) {
> + DRM_DEV_ERROR(dev,
> + "can't find port point, please init lvds panel port!\n");
> + return -ENODEV;
> + }
> +
> + lvds->panel = of_drm_find_panel(port);
> + of_node_put(port);
> +
> + if (IS_ERR(lvds->panel))
> + return -EPROBE_DEFER;
> +
> + lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
Please use instead:
devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> +
> + if (IS_ERR(lvds->panel_bridge))
> + return PTR_ERR(lvds->panel_bridge);
> +
> + lvds->bridge.of_node = dev->of_node;
> + lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
> + lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
> +
> + dev_set_drvdata(dev, lvds);
> + devm_pm_runtime_enable(dev);
Error check is missing.
> +
> + drm_bridge_add(&lvds->bridge);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id mchp_lvds_dt_ids[] = {
> + {
> + .compatible = "microchip,sam9x75-lvds",
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
> +
> +static struct platform_driver mchp_lvds_driver = {
> + .probe = mchp_lvds_probe,
> + .driver = {
> + .name = "microchip-lvds",
> + .of_match_table = mchp_lvds_dt_ids,
> + },
> +};
> +module_platform_driver(mchp_lvds_driver);
> +
> +MODULE_AUTHOR("Manikandan Muralidharan <[email protected]>");
> +MODULE_AUTHOR("Dharma Balasubiramani <[email protected]>");
> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>
--
With best wishes
Dmitry
Hi Dmitry,
On 17/04/24 12:05 pm, Dmitry Baryshkov wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On Wed, Apr 17, 2024 at 08:11:35AM +0530, Dharma Balasubiramani wrote:
>> Add a new LVDS controller driver for sam9x7 which does the following:
>> - Prepares and enables the LVDS Peripheral clock
>> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
>> to the global bridge list.
>> - Identifies its output endpoint as panel and adds it to the encoder
>> display pipeline
>> - Enables the LVDS serializer
>>
>> Signed-off-by: Manikandan Muralidharan <[email protected]>
>> Signed-off-by: Dharma Balasubiramani <[email protected]>
>> ---
>> Changelog
>> v5 -> v6
>> - No Changes.
>> v4 -> v5
>> - Drop the unused variable 'format'.
>> - Use DRM wrapper for dev_err() to maintain uniformity.
>> - return -ENODEV instead of -EINVAL to maintain consistency with other DRM
>> bridge drivers.
>> v3 -> v4
>> - No changes.
>> v2 ->v3
>> - Correct Typo error "serializer".
>> - Consolidate get() and prepare() functions and use devm_clk_get_prepared().
>> - Remove unused variable 'ret' in probe().
>> - Use devm_pm_runtime_enable() and drop the mchp_lvds_remove().
>> v1 -> v2
>> - Drop 'res' variable and combine two lines into one.
>> - Handle deferred probe properly, use dev_err_probe().
>> - Don't print anything on deferred probe. Dropped print.
>> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
>> - symbol 'mchp_lvds_driver' was not declared. It should be static.
>> ---
>> drivers/gpu/drm/bridge/Kconfig | 7 +
>> drivers/gpu/drm/bridge/Makefile | 1 +
>> drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++++++++
>> 3 files changed, 236 insertions(+)
>> create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index efd996f6c138..889098e2d65f 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -190,6 +190,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
>> to DP++. This is used with the i.MX6 imx-ldb
>> driver. You are likely to say N here.
>>
>> +config DRM_MICROCHIP_LVDS_SERIALIZER
>> + tristate "Microchip LVDS serializer support"
>> + depends on OF
>> + depends on DRM_ATMEL_HLCDC
>> + help
>> + Support for Microchip's LVDS serializer.
>> +
>> config DRM_NWL_MIPI_DSI
>> tristate "Northwest Logic MIPI DSI Host controller"
>> depends on DRM
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index 017b5832733b..7df87b582dca 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
>> obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
>> obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
>> obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
>> +obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
>> obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>> obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
>> diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
>> new file mode 100644
>> index 000000000000..149704f498a6
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/microchip-lvds.c
>> @@ -0,0 +1,228 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
>> + *
>> + * Author: Manikandan Muralidharan <[email protected]>
>> + * Author: Dharma Balasubiramani <[email protected]>
>> + *
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/component.h>
>> +#include <linux/delay.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/pinctrl/devinfo.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/regmap.h>
>> +#include <linux/reset.h>
>> +
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_print.h>
>> +#include <drm/drm_probe_helper.h>
>> +#include <drm/drm_simple_kms_helper.h>
>> +
>> +#define LVDS_POLL_TIMEOUT_MS 1000
>> +
>> +/* LVDSC register offsets */
>> +#define LVDSC_CR 0x00
>> +#define LVDSC_CFGR 0x04
>> +#define LVDSC_SR 0x0C
>> +#define LVDSC_WPMR 0xE4
>> +
>> +/* Bitfields in LVDSC_CR (Control Register) */
>> +#define LVDSC_CR_SER_EN BIT(0)
>> +
>> +/* Bitfields in LVDSC_CFGR (Configuration Register) */
>> +#define LVDSC_CFGR_PIXSIZE_24BITS 0
>> +#define LVDSC_CFGR_DEN_POL_HIGH 0
>> +#define LVDSC_CFGR_DC_UNBALANCED 0
>> +#define LVDSC_CFGR_MAPPING_JEIDA BIT(6)
>> +
>> +/*Bitfields in LVDSC_SR */
>> +#define LVDSC_SR_CS BIT(0)
>> +
>> +/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
>> +#define LVDSC_WPMR_WPKEY_MASK GENMASK(31, 8)
>> +#define LVDSC_WPMR_WPKEY_PSSWD 0x4C5644
>> +
>> +struct mchp_lvds {
>> + struct device *dev;
>> + void __iomem *regs;
>> + struct clk *pclk;
>> + struct drm_panel *panel;
>> + struct drm_bridge bridge;
>> + struct drm_bridge *panel_bridge;
>> +};
>> +
>> +static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
>> +{
>> + return container_of(bridge, struct mchp_lvds, bridge);
>> +}
>> +
>> +static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
>> +{
>> + return readl_relaxed(lvds->regs + offset);
>> +}
>> +
>> +static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
>> +{
>> + writel_relaxed(val, lvds->regs + offset);
>> +}
>> +
>> +static void lvds_serialiser_on(struct mchp_lvds *lvds)
>> +{
>> + unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
>> +
>> + /* The LVDSC registers can only be written if WPEN is cleared */
>> + lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
>> + LVDSC_WPMR_WPKEY_MASK));
>> +
>> + /* Wait for the status of configuration registers to be changed */
>> + while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
>> + if (time_after(jiffies, timeout)) {
>> + DRM_DEV_ERROR(lvds->dev, "%s: timeout error\n",
>> + __func__);
>> + return;
>> + }
>> + usleep_range(1000, 2000);
>> + }
>> +
>> + /* Configure the LVDSC */
>> + lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
>> + LVDSC_CFGR_DC_UNBALANCED |
>> + LVDSC_CFGR_DEN_POL_HIGH |
>> + LVDSC_CFGR_PIXSIZE_24BITS));
>> +
>> + /* Enable the LVDS serializer */
>> + lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
>> +}
>> +
>> +static int mchp_lvds_attach(struct drm_bridge *bridge,
>> + enum drm_bridge_attach_flags flags)
>> +{
>> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> +
>> + bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
>
> Why do you need to touch encoder_type here? It's not your bridge's
> responsibility.
Indeed, I've verified it across other bridge drivers too. Thank you for
bringing it to my attention. I will remove setting the encoder type here.
>
>> +
>> + return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
>> + bridge, flags);
>> +}
>> +
>> +static void mchp_lvds_enable(struct drm_bridge *bridge)
>> +{
>> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> + int ret;
>> +
>> + ret = clk_enable(lvds->pclk);
I will change this into clk_prepare_enable as we are dropping the
prepared version in the probe().
>> + if (ret < 0) {
>> + DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
>> + return;
>> + }
>> +
>> + ret = pm_runtime_get_sync(lvds->dev);
>> + if (ret < 0) {
>> + DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
>> + clk_disable(lvds->pclk);
>
> This can result in unbalanced clk_disable(), if pm_runtime_get_sync()
> fails. This function calls clk_disable(), but the framework has no way
> to know that .enable() was not successful and calls .disable(), which
> also calls clk_disable( >
> Please consider turning pclk into pm_clk so that its state is managed
> automatically (or at least moving clk_enable/disable into pm_ops).
This process appears rather intricate. May I suggest omitting the
'clk_disable' operation here?
>
>> + return;
>> + }
>> +
>> + lvds_serialiser_on(lvds);
>> +}
>> +
>> +static void mchp_lvds_disable(struct drm_bridge *bridge)
>> +{
>> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> +
>> + pm_runtime_put(lvds->dev);
>> + clk_disable(lvds->pclk);
>> +}
>> +
>> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
>> + .attach = mchp_lvds_attach,
>> + .enable = mchp_lvds_enable,
>> + .disable = mchp_lvds_disable,
>> +};
>> +
>> +static int mchp_lvds_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct mchp_lvds *lvds;
>> + struct device_node *port;
>> +
>> + if (!dev->of_node)
>> + return -ENODEV;
>> +
>> + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
>> + if (!lvds)
>> + return -ENOMEM;
>> +
>> + lvds->dev = dev;
>> +
>> + lvds->regs = devm_ioremap_resource(lvds->dev,
>> + platform_get_resource(pdev, IORESOURCE_MEM, 0));
>> + if (IS_ERR(lvds->regs))
>> + return PTR_ERR(lvds->regs);
>> +
>> + lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
>
> Why do you need _prepared version?
I will change this to just devm_clk_get().
>
>> + if (IS_ERR(lvds->pclk))
>> + return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
>> + "could not get pclk_lvds prepared\n");
>> +
>> + port = of_graph_get_remote_node(dev->of_node, 1, 0);
>> + if (!port) {
>> + DRM_DEV_ERROR(dev,
>> + "can't find port point, please init lvds panel port!\n");
>> + return -ENODEV;
>> + }
>> +
>> + lvds->panel = of_drm_find_panel(port);
>> + of_node_put(port);
>> +
>> + if (IS_ERR(lvds->panel))
>> + return -EPROBE_DEFER;
>> +
>> + lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
>
> Please use instead:
>
> devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
Sure, Noted. Thanks.
>
>> +
>> + if (IS_ERR(lvds->panel_bridge))
>> + return PTR_ERR(lvds->panel_bridge);
>> +
>> + lvds->bridge.of_node = dev->of_node;
>> + lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
>> + lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
>> +
>> + dev_set_drvdata(dev, lvds);
>> + devm_pm_runtime_enable(dev);
>
> Error check is missing.
Sure, I will add this
ret = devm_pm_runtime_enable(dev);
if (ret < 0) {
DRM_DEV_ERROR(lvds->dev, "failed to enable pm runtime:
%d\n", ret);
return ret;
}
>
>> +
>> + drm_bridge_add(&lvds->bridge);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id mchp_lvds_dt_ids[] = {
>> + {
>> + .compatible = "microchip,sam9x75-lvds",
>> + },
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
>> +
>> +static struct platform_driver mchp_lvds_driver = {
>> + .probe = mchp_lvds_probe,
>> + .driver = {
>> + .name = "microchip-lvds",
>> + .of_match_table = mchp_lvds_dt_ids,
>> + },
>> +};
>> +module_platform_driver(mchp_lvds_driver);
>> +
>> +MODULE_AUTHOR("Manikandan Muralidharan <[email protected]>");
>> +MODULE_AUTHOR("Dharma Balasubiramani <[email protected]>");
>> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.25.1
>>
>
> --
> With best wishes
> Dmitry
--
With Best Regards,
Dharma B.
On Thu, Apr 18, 2024 at 03:54:53AM +0000, [email protected] wrote:
> Hi Dmitry,
>
> On 17/04/24 12:05 pm, Dmitry Baryshkov wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >
> > On Wed, Apr 17, 2024 at 08:11:35AM +0530, Dharma Balasubiramani wrote:
> >> Add a new LVDS controller driver for sam9x7 which does the following:
> >> - Prepares and enables the LVDS Peripheral clock
> >> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
> >> to the global bridge list.
> >> - Identifies its output endpoint as panel and adds it to the encoder
> >> display pipeline
> >> - Enables the LVDS serializer
> >>
> >> Signed-off-by: Manikandan Muralidharan <[email protected]>
> >> Signed-off-by: Dharma Balasubiramani <[email protected]>
> >> ---
> >> Changelog
> >> v5 -> v6
> >> - No Changes.
> >> v4 -> v5
> >> - Drop the unused variable 'format'.
> >> - Use DRM wrapper for dev_err() to maintain uniformity.
> >> - return -ENODEV instead of -EINVAL to maintain consistency with other DRM
> >> bridge drivers.
> >> v3 -> v4
> >> - No changes.
> >> v2 ->v3
> >> - Correct Typo error "serializer".
> >> - Consolidate get() and prepare() functions and use devm_clk_get_prepared().
> >> - Remove unused variable 'ret' in probe().
> >> - Use devm_pm_runtime_enable() and drop the mchp_lvds_remove().
> >> v1 -> v2
> >> - Drop 'res' variable and combine two lines into one.
> >> - Handle deferred probe properly, use dev_err_probe().
> >> - Don't print anything on deferred probe. Dropped print.
> >> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
> >> - symbol 'mchp_lvds_driver' was not declared. It should be static.
> >> ---
> >> drivers/gpu/drm/bridge/Kconfig | 7 +
> >> drivers/gpu/drm/bridge/Makefile | 1 +
> >> drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++++++++
> >> 3 files changed, 236 insertions(+)
> >> create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
> >>
> >> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> >> index efd996f6c138..889098e2d65f 100644
> >> --- a/drivers/gpu/drm/bridge/Kconfig
> >> +++ b/drivers/gpu/drm/bridge/Kconfig
[skipped]
> >> + if (ret < 0) {
> >> + DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
> >> + return;
> >> + }
> >> +
> >> + ret = pm_runtime_get_sync(lvds->dev);
> >> + if (ret < 0) {
> >> + DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
> >> + clk_disable(lvds->pclk);
> >
> > This can result in unbalanced clk_disable(), if pm_runtime_get_sync()
> > fails. This function calls clk_disable(), but the framework has no way
> > to know that .enable() was not successful and calls .disable(), which
> > also calls clk_disable( >
> > Please consider turning pclk into pm_clk so that its state is managed
> > automatically (or at least moving clk_enable/disable into pm_ops).
>
> This process appears rather intricate. May I suggest omitting the
> 'clk_disable' operation here?
Yes
>
> >
> >> + return;
> >> + }
> >> +
> >> + lvds_serialiser_on(lvds);
> >> +}
> >> +
> >> +static void mchp_lvds_disable(struct drm_bridge *bridge)
> >> +{
> >> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> >> +
> >> + pm_runtime_put(lvds->dev);
> >> + clk_disable(lvds->pclk);
> >> +}
> >> +
> >> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
> >> + .attach = mchp_lvds_attach,
> >> + .enable = mchp_lvds_enable,
> >> + .disable = mchp_lvds_disable,
> >> +};
> >> +
> >> +static int mchp_lvds_probe(struct platform_device *pdev)
> >> +{
> >> + struct device *dev = &pdev->dev;
> >> + struct mchp_lvds *lvds;
> >> + struct device_node *port;
> >> +
> >> + if (!dev->of_node)
> >> + return -ENODEV;
> >> +
> >> + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
> >> + if (!lvds)
> >> + return -ENOMEM;
> >> +
> >> + lvds->dev = dev;
> >> +
> >> + lvds->regs = devm_ioremap_resource(lvds->dev,
> >> + platform_get_resource(pdev, IORESOURCE_MEM, 0));
> >> + if (IS_ERR(lvds->regs))
> >> + return PTR_ERR(lvds->regs);
> >> +
> >> + lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
> >
> > Why do you need _prepared version?
>
> I will change this to just devm_clk_get().
>
> >
> >> + if (IS_ERR(lvds->pclk))
> >> + return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
> >> + "could not get pclk_lvds prepared\n");
> >> +
> >> + port = of_graph_get_remote_node(dev->of_node, 1, 0);
> >> + if (!port) {
> >> + DRM_DEV_ERROR(dev,
> >> + "can't find port point, please init lvds panel port!\n");
> >> + return -ENODEV;
> >> + }
> >> +
> >> + lvds->panel = of_drm_find_panel(port);
> >> + of_node_put(port);
> >> +
> >> + if (IS_ERR(lvds->panel))
> >> + return -EPROBE_DEFER;
> >> +
> >> + lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
> >
> > Please use instead:
> >
> > devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
>
> Sure, Noted. Thanks.
> >
> >> +
> >> + if (IS_ERR(lvds->panel_bridge))
> >> + return PTR_ERR(lvds->panel_bridge);
> >> +
> >> + lvds->bridge.of_node = dev->of_node;
> >> + lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
> >> + lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
> >> +
> >> + dev_set_drvdata(dev, lvds);
> >> + devm_pm_runtime_enable(dev);
> >
> > Error check is missing.
>
> Sure, I will add this
>
> ret = devm_pm_runtime_enable(dev);
> if (ret < 0) {
> DRM_DEV_ERROR(lvds->dev, "failed to enable pm runtime:
DRM_DEV_ERROR is deprecated, plese use suitable replacement.
> %d\n", ret);
> return ret;
> }
>
>
--
With best wishes
Dmitry
On 18/04/24 11:55 am, Dmitry Baryshkov wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On Thu, Apr 18, 2024 at 03:54:53AM +0000, [email protected] wrote:
>> Hi Dmitry,
>>
>> On 17/04/24 12:05 pm, Dmitry Baryshkov wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> On Wed, Apr 17, 2024 at 08:11:35AM +0530, Dharma Balasubiramani wrote:
>>>> Add a new LVDS controller driver for sam9x7 which does the following:
>>>> - Prepares and enables the LVDS Peripheral clock
>>>> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
>>>> to the global bridge list.
>>>> - Identifies its output endpoint as panel and adds it to the encoder
>>>> display pipeline
>>>> - Enables the LVDS serializer
>>>>
>>>> Signed-off-by: Manikandan Muralidharan <[email protected]>
>>>> Signed-off-by: Dharma Balasubiramani <[email protected]>
>>>> ---
>>>> Changelog
>>>> v5 -> v6
>>>> - No Changes.
>>>> v4 -> v5
>>>> - Drop the unused variable 'format'.
>>>> - Use DRM wrapper for dev_err() to maintain uniformity.
>>>> - return -ENODEV instead of -EINVAL to maintain consistency with other DRM
>>>> bridge drivers.
>>>> v3 -> v4
>>>> - No changes.
>>>> v2 ->v3
>>>> - Correct Typo error "serializer".
>>>> - Consolidate get() and prepare() functions and use devm_clk_get_prepared().
>>>> - Remove unused variable 'ret' in probe().
>>>> - Use devm_pm_runtime_enable() and drop the mchp_lvds_remove().
>>>> v1 -> v2
>>>> - Drop 'res' variable and combine two lines into one.
>>>> - Handle deferred probe properly, use dev_err_probe().
>>>> - Don't print anything on deferred probe. Dropped print.
>>>> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
>>>> - symbol 'mchp_lvds_driver' was not declared. It should be static.
>>>> ---
>>>> drivers/gpu/drm/bridge/Kconfig | 7 +
>>>> drivers/gpu/drm/bridge/Makefile | 1 +
>>>> drivers/gpu/drm/bridge/microchip-lvds.c | 228 ++++++++++++++++++++++++
>>>> 3 files changed, 236 insertions(+)
>>>> create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>>>> index efd996f6c138..889098e2d65f 100644
>>>> --- a/drivers/gpu/drm/bridge/Kconfig
>>>> +++ b/drivers/gpu/drm/bridge/Kconfig
>
> [skipped]
>
>>>> + if (ret < 0) {
>>>> + DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
>>>> + return;
>>>> + }
>>>> +
>>>> + ret = pm_runtime_get_sync(lvds->dev);
>>>> + if (ret < 0) {
>>>> + DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
>>>> + clk_disable(lvds->pclk);
>>>
>>> This can result in unbalanced clk_disable(), if pm_runtime_get_sync()
>>> fails. This function calls clk_disable(), but the framework has no way
>>> to know that .enable() was not successful and calls .disable(), which
>>> also calls clk_disable( >
>>> Please consider turning pclk into pm_clk so that its state is managed
>>> automatically (or at least moving clk_enable/disable into pm_ops).
>>
>> This process appears rather intricate. May I suggest omitting the
>> 'clk_disable' operation here?
>
> Yes
>
>>
>>>
>>>> + return;
>>>> + }
>>>> +
>>>> + lvds_serialiser_on(lvds);
>>>> +}
>>>> +
>>>> +static void mchp_lvds_disable(struct drm_bridge *bridge)
>>>> +{
>>>> + struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>>>> +
>>>> + pm_runtime_put(lvds->dev);
>>>> + clk_disable(lvds->pclk);
>>>> +}
>>>> +
>>>> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
>>>> + .attach = mchp_lvds_attach,
>>>> + .enable = mchp_lvds_enable,
>>>> + .disable = mchp_lvds_disable,
>>>> +};
>>>> +
>>>> +static int mchp_lvds_probe(struct platform_device *pdev)
>>>> +{
>>>> + struct device *dev = &pdev->dev;
>>>> + struct mchp_lvds *lvds;
>>>> + struct device_node *port;
>>>> +
>>>> + if (!dev->of_node)
>>>> + return -ENODEV;
>>>> +
>>>> + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
>>>> + if (!lvds)
>>>> + return -ENOMEM;
>>>> +
>>>> + lvds->dev = dev;
>>>> +
>>>> + lvds->regs = devm_ioremap_resource(lvds->dev,
>>>> + platform_get_resource(pdev, IORESOURCE_MEM, 0));
>>>> + if (IS_ERR(lvds->regs))
>>>> + return PTR_ERR(lvds->regs);
>>>> +
>>>> + lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
>>>
>>> Why do you need _prepared version?
>>
>> I will change this to just devm_clk_get().
>>
>>>
>>>> + if (IS_ERR(lvds->pclk))
>>>> + return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
>>>> + "could not get pclk_lvds prepared\n");
>>>> +
>>>> + port = of_graph_get_remote_node(dev->of_node, 1, 0);
>>>> + if (!port) {
>>>> + DRM_DEV_ERROR(dev,
>>>> + "can't find port point, please init lvds panel port!\n");
>>>> + return -ENODEV;
>>>> + }
>>>> +
>>>> + lvds->panel = of_drm_find_panel(port);
>>>> + of_node_put(port);
>>>> +
>>>> + if (IS_ERR(lvds->panel))
>>>> + return -EPROBE_DEFER;
>>>> +
>>>> + lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
>>>
>>> Please use instead:
>>>
>>> devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
>>
>> Sure, Noted. Thanks.
>>>
>>>> +
>>>> + if (IS_ERR(lvds->panel_bridge))
>>>> + return PTR_ERR(lvds->panel_bridge);
>>>> +
>>>> + lvds->bridge.of_node = dev->of_node;
>>>> + lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
>>>> + lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
>>>> +
>>>> + dev_set_drvdata(dev, lvds);
>>>> + devm_pm_runtime_enable(dev);
>>>
>>> Error check is missing.
>>
>> Sure, I will add this
>>
>> ret = devm_pm_runtime_enable(dev);
>> if (ret < 0) {
>> DRM_DEV_ERROR(lvds->dev, "failed to enable pm runtime:
>
> DRM_DEV_ERROR is deprecated, plese use suitable replacement.
Sure, I will replace DRM_DEV_ERROR() with dev_err().
>
>> %d\n", ret);
>> return ret;
>> }
>>
>>
>
> --
> With best wishes
> Dmitry
--
With Best Regards,
Dharma B.