Add support for Kinetic KTZ8866 backlight, which is used in
Xiaomi tablet, Mi Pad 5 series. This driver lightly based on
downstream implementation [1].
[1] https://github.com/MiCode/Xiaomi_Kernel_OpenSource/blob/elish-r-oss/drivers/video/backlight/ktz8866.c
Signed-off-by: Jianhua Lu <[email protected]>
---
Changes in v2:
- Add missing staitc modifier to ktz8866_write function.
Changes in v3:
- Add 2022 to Copyright line.
- Sort headers
- Remove meaningless comment
- Use definitions instead of hardcoding.
- Add missing maintainer info
MAINTAINERS | 6 +
drivers/video/backlight/Kconfig | 8 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/ktz8866.c | 180 ++++++++++++++++++++++++++++++
drivers/video/backlight/ktz8866.h | 31 +++++
5 files changed, 226 insertions(+)
create mode 100644 drivers/video/backlight/ktz8866.c
create mode 100644 drivers/video/backlight/ktz8866.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 1daadaa4d48b..b33385b5fd3c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11507,6 +11507,12 @@ M: John Hawley <[email protected]>
S: Maintained
F: tools/testing/ktest
+KTZ8866 BACKLIGHT DRIVER
+M: Jianhua Lu <[email protected]>
+S: Maintained
+F: Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
+F: drivers/video/backlight/ktz8866.c
+
L3MDEV
M: David Ahern <[email protected]>
L: [email protected]
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 936ba1e4d35e..2845fd7e33ad 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -190,6 +190,14 @@ config BACKLIGHT_KTD253
which is a 1-wire GPIO-controlled backlight found in some mobile
phones.
+config BACKLIGHT_KTZ8866
+ tristate "Backlight Driver for Kinetic KTZ8866"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ Say Y to enabled the backlight driver for the Kinetic KTZ8866
+ found in Xiaomi Mi Pad 5 series.
+
config BACKLIGHT_LM3533
tristate "Backlight Driver for LM3533"
depends on MFD_LM3533
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index e815f3f1deff..f70a819c304c 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO) += ipaq_micro_bl.o
obj-$(CONFIG_BACKLIGHT_KTD253) += ktd253-backlight.o
+obj-$(CONFIG_BACKLIGHT_KTZ8866) += ktz8866.o
obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o
obj-$(CONFIG_BACKLIGHT_LM3630A) += lm3630a_bl.o
obj-$(CONFIG_BACKLIGHT_LM3639) += lm3639_bl.o
diff --git a/drivers/video/backlight/ktz8866.c b/drivers/video/backlight/ktz8866.c
new file mode 100644
index 000000000000..ea641bdfc4d2
--- /dev/null
+++ b/drivers/video/backlight/ktz8866.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Backlight driver for the Kinetic KTZ8866
+ *
+ * Copyright (C) 2022 Jianhua Lu <[email protected]>
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include "ktz8866.h"
+
+#define DEFAULT_BRIGHTNESS 1500
+#define MAX_BRIGHTNESS 2047
+#define REG_MAX 0x15
+
+#define BL_EN_BIT BIT(6)
+#define BL_CURRENT_SINKS 0x1F
+#define BL_OVP_LIMIT 0x33
+#define LED_CURRENT_RAMPING_TIME 0xBD
+#define LED_DIMMING_TIME 0x11
+#define LCD_BIAS_EN 0x9F
+#define LED_CURRENT 0xF9
+
+#define low_3_bit(x) ((x)&0x7)
+#define high_8_bit(x) ((x >> 3) & 0xFF)
+
+struct ktz8866 {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ bool state;
+};
+
+enum {
+ LED_OFF,
+ LED_ON,
+};
+
+static const struct regmap_config ktz8866_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = REG_MAX,
+};
+
+static int ktz8866_write(struct ktz8866 *ktz, unsigned int reg,
+ unsigned int val)
+{
+ return regmap_write(ktz->regmap, reg, val);
+}
+
+static int ktz8866_update_bits(struct ktz8866 *ktz, unsigned int reg,
+ unsigned int mask, unsigned int val)
+{
+ return regmap_update_bits(ktz->regmap, reg, mask, val);
+}
+
+static int ktz8866_backlight_update_status(struct backlight_device *backlight_dev)
+{
+ struct ktz8866 *ktz = bl_get_data(backlight_dev);
+ unsigned int brightness = backlight_get_brightness(backlight_dev);
+
+ if (!ktz->state && brightness > 0) {
+ ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, BL_EN_BIT);
+ ktz->state = LED_ON;
+ } else if (brightness == 0) {
+ ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, 0);
+ ktz->state = LED_OFF;
+ msleep(10);
+ }
+
+ /* Set brightness */
+ ktz8866_write(ktz, BL_BRT_LSB, low_3_bit(brightness));
+ ktz8866_write(ktz, BL_BRT_MSB, high_8_bit(brightness));
+
+ return 0;
+}
+
+static const struct backlight_ops ktz8866_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = ktz8866_backlight_update_status,
+};
+
+static void ktz8866_init(struct ktz8866 *ktz)
+{
+ /* Enable 1~5 current sinks */
+ ktz8866_write(ktz, BL_EN, BL_CURRENT_SINKS);
+ /* Backlight OVP 26.4V */
+ ktz8866_write(ktz, BL_CFG1, BL_OVP_LIMIT);
+ /* LED current ramping time 128ms */
+ ktz8866_write(ktz, BL_CFG2, LED_CURRENT_RAMPING_TIME);
+ /* LED on/off ramping time 1ms */
+ ktz8866_write(ktz, BL_DIMMING, LED_DIMMING_TIME);
+ /* Enable OUTP and OUTN via pin ENP and ENN */
+ ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);
+ /* Backlight Full-scale LED Current 30.0mA */
+ ktz8866_write(ktz, FULL_SCALE_CURRENT, LED_CURRENT);
+}
+
+static int ktz8866_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct backlight_device *backlight_dev;
+ struct backlight_properties props;
+ struct ktz8866 *ktz;
+
+ ktz = devm_kzalloc(&client->dev, sizeof(*ktz), GFP_KERNEL);
+ if (!ktz)
+ return -ENOMEM;
+
+ ktz->client = client;
+ ktz->regmap = devm_regmap_init_i2c(client, &ktz8866_regmap_config);
+
+ if (IS_ERR(ktz->regmap)) {
+ dev_err(&client->dev, "failed to init regmap\n");
+ return PTR_ERR(ktz->regmap);
+ }
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = MAX_BRIGHTNESS;
+ props.brightness = clamp_t(unsigned int, DEFAULT_BRIGHTNESS, 0,
+ props.max_brightness);
+
+ backlight_dev = devm_backlight_device_register(
+ &client->dev, "ktz8866-backlight", &client->dev, ktz,
+ &ktz8866_backlight_ops, &props);
+
+ if (IS_ERR(backlight_dev)) {
+ dev_err(&client->dev, "failed to register backlight device\n");
+ return PTR_ERR(backlight_dev);
+ }
+
+ ktz8866_init(ktz);
+
+ i2c_set_clientdata(client, backlight_dev);
+ backlight_update_status(backlight_dev);
+
+ return 0;
+}
+
+static void ktz8866_remove(struct i2c_client *client)
+{
+ struct backlight_device *backlight_dev = i2c_get_clientdata(client);
+
+ backlight_dev->props.brightness = 0;
+ backlight_update_status(backlight_dev);
+}
+
+static const struct i2c_device_id ktz8866_ids[] = {
+ { "ktz8866", 0 },
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, ktz8866_ids);
+
+static const struct of_device_id ktz8866_match_table[] = {
+ {
+ .compatible = "kinetic,ktz8866",
+ },
+ {},
+};
+
+static struct i2c_driver ktz8866_driver = {
+ .driver = {
+ .name = "ktz8866",
+ .of_match_table = ktz8866_match_table,
+ },
+ .probe = ktz8866_probe,
+ .remove = ktz8866_remove,
+ .id_table = ktz8866_ids,
+};
+
+module_i2c_driver(ktz8866_driver);
+
+MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver");
+MODULE_AUTHOR("Jianhua Lu <[email protected]>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/video/backlight/ktz8866.h b/drivers/video/backlight/ktz8866.h
new file mode 100644
index 000000000000..b0ed8cbee608
--- /dev/null
+++ b/drivers/video/backlight/ktz8866.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Register definitions for Kinetic KTZ8866 backlight
+ *
+ * Copyright (C) 2022 Jianhua Lu <[email protected]>
+ */
+
+#ifndef KTZ8866_H
+#define KTZ8866_H
+
+#define DEVICE_ID 0x01
+#define BL_CFG1 0x02
+#define BL_CFG2 0x03
+#define BL_BRT_LSB 0x04
+#define BL_BRT_MSB 0x05
+#define BL_EN 0x08
+#define LCD_BIAS_CFG1 0x09
+#define LCD_BIAS_CFG2 0x0A
+#define LCD_BIAS_CFG3 0x0B
+#define LCD_BOOST_CFG 0x0C
+#define OUTP_CFG 0x0D
+#define OUTN_CFG 0x0E
+#define FLAG 0x0F
+#define BL_OPTION1 0x10
+#define BL_OPTION2 0x11
+#define PWM2DIG_LSBs 0x12
+#define PWM2DIG_MSBs 0x13
+#define BL_DIMMING 0x14
+#define FULL_SCALE_CURRENT 0x15
+
+#endif /* KTZ8866_H */
--
2.38.2
Add Kinetic KTZ8866 backlight binding documentation.
Signed-off-by: Jianhua Lu <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
---
Changes in v2:
- Remove "items" between "compatible" and "const: kinetic,ktz8866"
- Change "additionalProperties" to "unevaluatedProperties"
Changes in v3:
- Add Krzysztof's R-b
.../leds/backlight/kinetic,ktz8866.yaml | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
diff --git a/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
new file mode 100644
index 000000000000..c63c21bf69d6
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/kinetic,ktz8866.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Kinetic Technologies KTZ8866 backlight
+
+maintainers:
+ - Jianhua Lu <[email protected]>
+
+description: |
+ The Kinetic Technologies KTZ8866 is a high efficiency 6-sinks led backlight
+ with dual lcd bias power.
+ https://www.kinet-ic.com/ktz8866/
+
+allOf:
+ - $ref: common.yaml#
+
+properties:
+ compatible:
+ const: kinetic,ktz8866
+
+required:
+ - compatible
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ backlight {
+ compatible = "kinetic,ktz8866";
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&bl_en_default>;
+ };
--
2.38.2
On Thu, Dec 22, 2022 at 08:54:40PM +0800, Jianhua Lu wrote:
> Add support for Kinetic KTZ8866 backlight, which is used in
> Xiaomi tablet, Mi Pad 5 series. This driver lightly based on
> downstream implementation [1].
> [1] https://github.com/MiCode/Xiaomi_Kernel_OpenSource/blob/elish-r-oss/drivers/video/backlight/ktz8866.c
>
> Signed-off-by: Jianhua Lu <[email protected]>
> ---
> Changes in v2:
> - Add missing staitc modifier to ktz8866_write function.
>
> Changes in v3:
> - Add 2022 to Copyright line.
> - Sort headers
> - Remove meaningless comment
> - Use definitions instead of hardcoding.
> - Add missing maintainer info
>
> MAINTAINERS | 6 +
> drivers/video/backlight/Kconfig | 8 ++
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/ktz8866.c | 180 ++++++++++++++++++++++++++++++
> drivers/video/backlight/ktz8866.h | 31 +++++
> 5 files changed, 226 insertions(+)
> create mode 100644 drivers/video/backlight/ktz8866.c
> create mode 100644 drivers/video/backlight/ktz8866.h
>
> diff --git a/drivers/video/backlight/ktz8866.c b/drivers/video/backlight/ktz8866.c
> new file mode 100644
> index 000000000000..ea641bdfc4d2
> --- /dev/null
> +++ b/drivers/video/backlight/ktz8866.c
> @@ -0,0 +1,180 @@
> +
> +#define BL_EN_BIT BIT(6)
> +#define BL_CURRENT_SINKS 0x1F
> +#define BL_OVP_LIMIT 0x33
> +#define LED_CURRENT_RAMPING_TIME 0xBD
> +#define LED_DIMMING_TIME 0x11
> +#define LCD_BIAS_EN 0x9F
> +#define LED_CURRENT 0xF9
> +
> +#define low_3_bit(x) ((x)&0x7)
> +#define high_8_bit(x) ((x >> 3) & 0xFF)
These don't seem to be particularly useful. They are used exactly once
so I think it is better just to implement the shifts directly
in ktz8866_backlight_update_status().
> +struct ktz8866 {
> + struct i2c_client *client;
> + struct regmap *regmap;
> + bool state;
> +};
> +
> +enum {
> + LED_OFF,
> + LED_ON,
> +};
Let's remove this emum. It is better to rename state to
led_on in order to make the code read well:
if (ktz->led_on) ...
ktz->led_on = true;
ktz->led_on = false;
> +static void ktz8866_init(struct ktz8866 *ktz)
> +{
> + /* Enable 1~5 current sinks */
> + ktz8866_write(ktz, BL_EN, BL_CURRENT_SINKS);
> + /* Backlight OVP 26.4V */
> + ktz8866_write(ktz, BL_CFG1, BL_OVP_LIMIT);
> + /* LED current ramping time 128ms */
> + ktz8866_write(ktz, BL_CFG2, LED_CURRENT_RAMPING_TIME);
> + /* LED on/off ramping time 1ms */
> + ktz8866_write(ktz, BL_DIMMING, LED_DIMMING_TIME);
> + /* Enable OUTP and OUTN via pin ENP and ENN */
> + ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);
> + /* Backlight Full-scale LED Current 30.0mA */
> + ktz8866_write(ktz, FULL_SCALE_CURRENT, LED_CURRENT);
> +}
Are these settings specific to the mipad 5 m/board? Many of these look
like they should be described in the devicetree rather than hardcoded
in the driver.
> +static int ktz8866_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct backlight_device *backlight_dev;
> + struct backlight_properties props;
> + struct ktz8866 *ktz;
> +
> + ktz = devm_kzalloc(&client->dev, sizeof(*ktz), GFP_KERNEL);
> + if (!ktz)
> + return -ENOMEM;
> +
> + ktz->client = client;
> + ktz->regmap = devm_regmap_init_i2c(client, &ktz8866_regmap_config);
> +
> + if (IS_ERR(ktz->regmap)) {
> + dev_err(&client->dev, "failed to init regmap\n");
> + return PTR_ERR(ktz->regmap);
> + }
> +
> + memset(&props, 0, sizeof(props));
> + props.type = BACKLIGHT_RAW;
> + props.max_brightness = MAX_BRIGHTNESS;
> + props.brightness = clamp_t(unsigned int, DEFAULT_BRIGHTNESS, 0,
> + props.max_brightness);
Please set the scale property correctly. "Unknown" is never correct for
new drivers.
> + backlight_dev = devm_backlight_device_register(
> + &client->dev, "ktz8866-backlight", &client->dev, ktz,
> + &ktz8866_backlight_ops, &props);
> +
> + if (IS_ERR(backlight_dev)) {
> + dev_err(&client->dev, "failed to register backlight device\n");
> + return PTR_ERR(backlight_dev);
> + }
> +
> + ktz8866_init(ktz);
> +
> + i2c_set_clientdata(client, backlight_dev);
> + backlight_update_status(backlight_dev);
> +
> + return 0;
> +}
> diff --git a/drivers/video/backlight/ktz8866.h b/drivers/video/backlight/ktz8866.h
> new file mode 100644
> index 000000000000..b0ed8cbee608
> --- /dev/null
> +++ b/drivers/video/backlight/ktz8866.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Register definitions for Kinetic KTZ8866 backlight
> + *
> + * Copyright (C) 2022 Jianhua Lu <[email protected]>
> + */
> +
> +#ifndef KTZ8866_H
> +#define KTZ8866_H
> +
> +#define DEVICE_ID 0x01
> +#define BL_CFG1 0x02
> +#define BL_CFG2 0x03
> +#define BL_BRT_LSB 0x04
> +#define BL_BRT_MSB 0x05
> +#define BL_EN 0x08
> +#define LCD_BIAS_CFG1 0x09
> +#define LCD_BIAS_CFG2 0x0A
> +#define LCD_BIAS_CFG3 0x0B
> +#define LCD_BOOST_CFG 0x0C
> +#define OUTP_CFG 0x0D
> +#define OUTN_CFG 0x0E
> +#define FLAG 0x0F
> +#define BL_OPTION1 0x10
> +#define BL_OPTION2 0x11
> +#define PWM2DIG_LSBs 0x12
> +#define PWM2DIG_MSBs 0x13
> +#define BL_DIMMING 0x14
> +#define FULL_SCALE_CURRENT 0x15
> +
> +#endif /* KTZ8866_H */
This header file is not required. Please remove and move any definitions
the driver needs into the C file.
Daniel.