[PATCH v3 1/2] dt-bindings: backlight: Add Texas Instruments LM3509

[PATCH v3 1/2] dt-bindings: backlight: Add Texas Instruments LM3509

[Patrick Gansterer]

Add Device Tree bindings for Texas Instruments LM3509 - a
High Efficiency Boost for White LED's and/or OLED Displays

Signed-off-by: Patrick Gansterer <paroga@paroga.com>
---
Changes in v3:
  Improved device tree bindings documentation style

v2: https://lore.kernel.org/all/20240308215617.1729664-1-paroga@paroga.com/

Changes in v2:
  Add device tree nodes for each output
  Addressed multiple smaller review comments

v1: https://lore.kernel.org/all/20240302212757.1871164-1-paroga@paroga.com/

 .../bindings/leds/backlight/ti,lm3509.yaml    | 139 ++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/ti,lm3509.yaml

diff --git a/Documentation/devicetree/bindings/leds/backlight/ti,lm3509.yaml b/Documentation/devicetree/bindings/leds/backlight/ti,lm3509.yaml
new file mode 100644
index 000000000000..b67f67648852
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/ti,lm3509.yaml
@@ -0,0 +1,139 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/ti,lm3509.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI LM3509 High Efficiency Boost for White LED's and/or OLED Displays
+
+maintainers:
+  - Patrick Gansterer <paroga@paroga.com>
+
+description:
+  The LM3509 current mode boost converter offers two separate outputs.
+  https://www.ti.com/product/LM3509
+
+properties:
+  compatible:
+    const: ti,lm3509
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  reset-gpios:
+    maxItems: 1
+
+  ti,brightness-rate-of-change-us:
+    description: Brightness Rate of Change in microseconds.
+    enum: [51, 13000, 26000, 52000]
+
+  ti,oled-mode:
+    description: Enable OLED mode.
+    type: boolean
+
+patternProperties:
+  "^led@[01]$":
+    type: object
+    description: Properties for a string of connected LEDs.
+
+    allOf:
+      - $ref: common.yaml#
+
+    properties:
+      reg:
+        description:
+          The control register that is used to program the two current sinks.
+          The LM3509 has two registers (BMAIN and BSUB) and are represented
+          as 0 or 1 in this property. The two current sinks can be controlled
+          independently with both registers, or register BMAIN can be
+          configured to control both sinks with the led-sources property.
+        minimum: 0
+        maximum: 1
+
+      label: true
+
+      led-sources:
+        allOf:
+          - minItems: 1
+            maxItems: 2
+            items:
+              minimum: 0
+              maximum: 1
+
+      default-brightness:
+        minimum: 0
+        maximum: 31
+        default: 18
+
+      max-brightness:
+        minimum: 0
+        maximum: 31
+        default: 31
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        backlight@36 {
+            compatible = "ti,lm3509";
+            reg = <0x36>;
+            reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>;
+
+            ti,oled-mode;
+            ti,brightness-rate-of-change-us = <52000>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            led@0 {
+                reg = <0>;
+                led-sources = <0 1>;
+                label = "lcd-backlight";
+                default-brightness = <12>;
+                max-brightness = <31>;
+            };
+        };
+    };
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        backlight@36 {
+            compatible = "ti,lm3509";
+            reg = <0x36>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            led@0 {
+                reg = <0>;
+                default-brightness = <12>;
+            };
+
+            led@1 {
+                reg = <1>;
+                default-brightness = <15>;
+            };
+        };
+    };
-- 
2.44.0

[PATCH v3 2/2] backlight: Add new lm3509 backlight driver

[Patrick Gansterer]

This is a general driver for LM3509 backlight chip of TI.
LM3509 is High Efficiency Boost for White LEDs and/or OLED Displays with
Dual Current Sinks. This driver supports OLED/White LED select, brightness
control and sub/main control.
The datasheet can be found at http://www.ti.com/product/lm3509.

Signed-off-by: Patrick Gansterer <paroga@paroga.com>
---
 drivers/video/backlight/Kconfig     |   7 +
 drivers/video/backlight/Makefile    |   1 +
 drivers/video/backlight/lm3509_bl.c | 340 ++++++++++++++++++++++++++++
 3 files changed, 348 insertions(+)
 create mode 100644 drivers/video/backlight/lm3509_bl.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index ea2d0d69bd8c..96ad5dc584b6 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -366,6 +366,13 @@ config BACKLIGHT_AAT2870
 	  If you have a AnalogicTech AAT2870 say Y to enable the
 	  backlight driver.
 
+config BACKLIGHT_LM3509
+	tristate "Backlight Driver for LM3509"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  This supports TI LM3509 Backlight Driver
+
 config BACKLIGHT_LM3630A
 	tristate "Backlight Driver for LM3630A"
 	depends on I2C && PWM
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 06966cb20459..51a4ac5d0530 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -35,6 +35,7 @@ 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-$(CONFIG_BACKLIGHT_LM3509)		+= lm3509_bl.o
 obj-$(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/lm3509_bl.c b/drivers/video/backlight/lm3509_bl.c
new file mode 100644
index 000000000000..bfad0aaffa0d
--- /dev/null
+++ b/drivers/video/backlight/lm3509_bl.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define LM3509_NAME "lm3509_bl"
+
+#define LM3509_SINK_MAIN 0
+#define LM3509_SINK_SUB 1
+#define LM3509_NUM_SINKS 2
+
+#define LM3509_DEF_BRIGHTNESS 0x12
+#define LM3509_MAX_BRIGHTNESS 0x1F
+
+#define REG_GP 0x10
+#define REG_BMAIN 0xA0
+#define REG_BSUB 0xB0
+#define REG_MAX 0xFF
+
+enum {
+	REG_GP_ENM_BIT = 0,
+	REG_GP_ENS_BIT,
+	REG_GP_UNI_BIT,
+	REG_GP_RMP0_BIT,
+	REG_GP_RMP1_BIT,
+	REG_GP_OLED_BIT,
+};
+
+struct lm3509_bl {
+	struct regmap *regmap;
+	struct backlight_device *bl_main;
+	struct backlight_device *bl_sub;
+	struct gpio_desc *reset_gpio;
+};
+
+struct lm3509_bl_led_pdata {
+	const char *label;
+	int led_sources;
+	u32 brightness;
+	u32 max_brightness;
+};
+
+static void lm3509_reset(struct lm3509_bl *data)
+{
+	if (data->reset_gpio) {
+		gpiod_set_value(data->reset_gpio, 1);
+		udelay(1);
+		gpiod_set_value(data->reset_gpio, 0);
+		udelay(10);
+	}
+}
+
+static int lm3509_update_status(struct backlight_device *bl,
+				unsigned int en_mask, unsigned int br_reg)
+{
+	struct lm3509_bl *data = bl_get_data(bl);
+	int ret;
+	bool en;
+
+	ret = regmap_write(data->regmap, br_reg, bl->props.brightness);
+	if (ret < 0)
+		return ret;
+
+	en = bl->props.power <= FB_BLANK_NORMAL;
+	return regmap_update_bits(data->regmap, REG_GP, en_mask,
+				  en ? en_mask : 0);
+}
+
+static int lm3509_main_update_status(struct backlight_device *bl)
+{
+	return lm3509_update_status(bl, BIT(REG_GP_ENM_BIT), REG_BMAIN);
+}
+
+static const struct backlight_ops lm3509_main_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = lm3509_main_update_status,
+};
+
+static int lm3509_sub_update_status(struct backlight_device *bl)
+{
+	return lm3509_update_status(bl, BIT(REG_GP_ENS_BIT), REG_BSUB);
+}
+
+static const struct backlight_ops lm3509_sub_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = lm3509_sub_update_status,
+};
+
+static struct backlight_device *
+lm3509_backlight_register(struct device *dev, const char *name_suffix,
+			  struct lm3509_bl *data,
+			  const struct backlight_ops *ops,
+			  const struct lm3509_bl_led_pdata *pdata)
+
+{
+	struct backlight_device *bd;
+	struct backlight_properties props;
+	const char *label = pdata->label;
+	char name[64];
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.brightness = pdata->brightness;
+	props.max_brightness = pdata->max_brightness;
+	props.power = pdata->brightness > 0 ? FB_BLANK_UNBLANK :
+					      FB_BLANK_POWERDOWN;
+
+	if (!label) {
+		snprintf(name, sizeof(name), "lm3509-%s-%s", dev_name(dev),
+			 name_suffix);
+		label = name;
+	}
+
+	bd = devm_backlight_device_register(dev, label, dev, data, ops, &props);
+	if (bd)
+		backlight_update_status(bd);
+
+	return bd;
+}
+
+static const struct regmap_config lm3509_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = REG_MAX,
+};
+
+static int lm3509_parse_led_sources(struct device_node *node,
+				    int default_led_sources)
+{
+	u32 sources[LM3509_NUM_SINKS];
+	int ret, num_sources, i;
+
+	num_sources = of_property_count_u32_elems(node, "led-sources");
+	if (num_sources < 0)
+		return default_led_sources;
+	else if (num_sources > ARRAY_SIZE(sources))
+		return -EINVAL;
+
+	ret = of_property_read_u32_array(node, "led-sources", sources,
+					 num_sources);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < num_sources; i++) {
+		if (sources[i] >= LM3509_NUM_SINKS)
+			return -EINVAL;
+
+		ret |= BIT(sources[i]);
+	}
+
+	return ret;
+}
+
+static int lm3509_parse_dt_node(struct device *dev,
+				struct lm3509_bl_led_pdata *pdata)
+{
+	struct device_node *child;
+	int seen_led_sources = 0;
+
+	for_each_child_of_node(dev->of_node, child) {
+		struct lm3509_bl_led_pdata *pd;
+		int ret;
+		u32 reg;
+		int valid_led_sources;
+
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret < 0)
+			return ret;
+		if (reg >= LM3509_NUM_SINKS)
+			return -EINVAL;
+		pd = &pdata[reg];
+
+		pd->led_sources = lm3509_parse_led_sources(child, BIT(reg));
+		if (pd->led_sources < 0)
+			return pd->led_sources;
+
+		if (reg == 0)
+			valid_led_sources = BIT(LM3509_SINK_MAIN) |
+					    BIT(LM3509_SINK_SUB);
+		else
+			valid_led_sources = BIT(LM3509_SINK_SUB);
+
+		if (pd->led_sources != (pd->led_sources & valid_led_sources))
+			return -EINVAL;
+
+		if (seen_led_sources & pd->led_sources)
+			return -EINVAL;
+
+		seen_led_sources |= pd->led_sources;
+
+		pd->label = NULL;
+		of_property_read_string(child, "label", &pd->label);
+
+		pd->max_brightness = LM3509_MAX_BRIGHTNESS;
+		of_property_read_u32(child, "max-brightness",
+				     &pd->max_brightness);
+		pd->max_brightness =
+			min_t(u32, pd->max_brightness, LM3509_MAX_BRIGHTNESS);
+
+		pd->brightness = LM3509_DEF_BRIGHTNESS;
+		of_property_read_u32(child, "default-brightness",
+				     &pd->brightness);
+		pd->brightness = min_t(u32, pd->brightness, pd->max_brightness);
+	}
+
+	return 0;
+}
+
+static int lm3509_probe(struct i2c_client *client)
+{
+	struct lm3509_bl *data;
+	struct device *dev = &client->dev;
+	int ret;
+	bool oled_mode = false;
+	unsigned int reg_gp_val = 0;
+	struct lm3509_bl_led_pdata pdata[LM3509_NUM_SINKS];
+	u32 rate_of_change = 0;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(dev, "i2c functionality check failed\n");
+		return -EOPNOTSUPP;
+	}
+
+	data = devm_kzalloc(dev, sizeof(struct lm3509_bl), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regmap = devm_regmap_init_i2c(client, &lm3509_regmap);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+	i2c_set_clientdata(client, data);
+
+	data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(data->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(data->reset_gpio),
+				     "Failed to get 'reset' gpio\n");
+
+	lm3509_reset(data);
+
+	memset(pdata, 0, sizeof(pdata));
+	ret = lm3509_parse_dt_node(dev, pdata);
+	if (ret)
+		return ret;
+
+	oled_mode = of_property_read_bool(dev->of_node, "ti,oled-mode");
+
+	if (!of_property_read_u32(dev->of_node,
+				  "ti,brightness-rate-of-change-us",
+				  &rate_of_change)) {
+		switch (rate_of_change) {
+		case 51:
+			reg_gp_val = 0;
+			break;
+		case 13000:
+			reg_gp_val = BIT(REG_GP_RMP1_BIT);
+			break;
+		case 26000:
+			reg_gp_val = BIT(REG_GP_RMP0_BIT);
+			break;
+		case 52000:
+			reg_gp_val = BIT(REG_GP_RMP0_BIT) |
+				     BIT(REG_GP_RMP1_BIT);
+			break;
+		default:
+			dev_warn(dev, "invalid rate of change %u\n",
+				 rate_of_change);
+			break;
+		}
+	}
+
+	if (pdata[0].led_sources ==
+	    (BIT(LM3509_SINK_MAIN) | BIT(LM3509_SINK_SUB)))
+		reg_gp_val |= BIT(REG_GP_UNI_BIT);
+	if (oled_mode)
+		reg_gp_val |= BIT(REG_GP_OLED_BIT);
+
+	ret = regmap_write(data->regmap, REG_GP, reg_gp_val);
+	if (ret < 0)
+		return ret;
+
+	if (pdata[0].led_sources) {
+		data->bl_main = lm3509_backlight_register(
+			dev, "main", data, &lm3509_main_ops, &pdata[0]);
+		if (IS_ERR(data->bl_main)) {
+			dev_err(dev, "failed to register main backlight\n");
+			return PTR_ERR(data->bl_main);
+		}
+	}
+
+	if (pdata[1].led_sources) {
+		data->bl_sub = lm3509_backlight_register(
+			dev, "sub", data, &lm3509_sub_ops, &pdata[1]);
+		if (IS_ERR(data->bl_sub)) {
+			dev_err(dev,
+				"failed to register secondary backlight\n");
+			return PTR_ERR(data->bl_sub);
+		}
+	}
+
+	return 0;
+}
+
+static void lm3509_remove(struct i2c_client *client)
+{
+	struct lm3509_bl *data = i2c_get_clientdata(client);
+
+	regmap_write(data->regmap, REG_GP, 0x00);
+}
+
+static const struct i2c_device_id lm3509_id[] = { { LM3509_NAME, 0 }, {} };
+
+MODULE_DEVICE_TABLE(i2c, lm3509_id);
+
+static const struct of_device_id lm3509_match_table[] = {
+	{
+		.compatible = "ti,lm3509",
+	},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, lm3509_match_table);
+
+static struct i2c_driver lm3509_i2c_driver = {
+	.driver = {
+		.name = LM3509_NAME,
+		.of_match_table = lm3509_match_table,
+	},
+	.probe = lm3509_probe,
+	.remove = lm3509_remove,
+	.id_table = lm3509_id,
+};
+
+module_i2c_driver(lm3509_i2c_driver);
+
+MODULE_DESCRIPTION("Texas Instruments Backlight driver for LM3509");
+MODULE_AUTHOR("Patrick Gansterer <paroga@paroga.com>");
+MODULE_LICENSE("GPL");
-- 
2.44.0

Re: [PATCH v3 1/2] dt-bindings: backlight: Add Texas Instruments LM3509

[Krzysztof Kozlowski]

On 09/03/2024 14:24, Patrick Gansterer wrote:
> Add Device Tree bindings for Texas Instruments LM3509 - a
> High Efficiency Boost for White LED's and/or OLED Displays
> 
> Signed-off-by: Patrick Gansterer <paroga@paroga.com>
> ---
> Changes in v3:
>   Improved device tree bindings documentation style

That's way too generic. Everything can be called style. If you only
improved style, then my comments regarding real issues like missing
defaults were not implemented?

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: backlight: Add Texas Instruments LM3509

[Krzysztof Kozlowski]

On 09/03/2024 14:24, Patrick Gansterer wrote:
> Add Device Tree bindings for Texas Instruments LM3509 - a
> High Efficiency Boost for White LED's and/or OLED Displays
> 
> Signed-off-by: Patrick Gansterer <paroga@paroga.com>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v3 2/2] backlight: Add new lm3509 backlight driver

[Sam Ravnborg]

Hi Patrick,

a few comments in the following.

	Sam

On Sat, Mar 09, 2024 at 02:24:56PM +0100, Patrick Gansterer wrote:
> This is a general driver for LM3509 backlight chip of TI.
> LM3509 is High Efficiency Boost for White LEDs and/or OLED Displays with
> Dual Current Sinks. This driver supports OLED/White LED select, brightness
> control and sub/main control.
> The datasheet can be found at http://www.ti.com/product/lm3509.
> 
> Signed-off-by: Patrick Gansterer <paroga@paroga.com>
> ---
>  drivers/video/backlight/Kconfig     |   7 +
>  drivers/video/backlight/Makefile    |   1 +
>  drivers/video/backlight/lm3509_bl.c | 340 ++++++++++++++++++++++++++++
>  3 files changed, 348 insertions(+)
>  create mode 100644 drivers/video/backlight/lm3509_bl.c
> 
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index ea2d0d69bd8c..96ad5dc584b6 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -366,6 +366,13 @@ config BACKLIGHT_AAT2870
>  	  If you have a AnalogicTech AAT2870 say Y to enable the
>  	  backlight driver.
>  
> +config BACKLIGHT_LM3509
> +	tristate "Backlight Driver for LM3509"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  This supports TI LM3509 Backlight Driver
> +
>  config BACKLIGHT_LM3630A
>  	tristate "Backlight Driver for LM3630A"
>  	depends on I2C && PWM
> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
> index 06966cb20459..51a4ac5d0530 100644
> --- a/drivers/video/backlight/Makefile
> +++ b/drivers/video/backlight/Makefile
> @@ -35,6 +35,7 @@ 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-$(CONFIG_BACKLIGHT_LM3509)		+= lm3509_bl.o
>  obj-$(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/lm3509_bl.c b/drivers/video/backlight/lm3509_bl.c
> new file mode 100644
> index 000000000000..bfad0aaffa0d
> --- /dev/null
> +++ b/drivers/video/backlight/lm3509_bl.c
> @@ -0,0 +1,340 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#define LM3509_NAME "lm3509_bl"
> +
> +#define LM3509_SINK_MAIN 0
> +#define LM3509_SINK_SUB 1
> +#define LM3509_NUM_SINKS 2
> +
> +#define LM3509_DEF_BRIGHTNESS 0x12
> +#define LM3509_MAX_BRIGHTNESS 0x1F
> +
> +#define REG_GP 0x10
> +#define REG_BMAIN 0xA0
> +#define REG_BSUB 0xB0
> +#define REG_MAX 0xFF
> +
> +enum {
> +	REG_GP_ENM_BIT = 0,
> +	REG_GP_ENS_BIT,
> +	REG_GP_UNI_BIT,
> +	REG_GP_RMP0_BIT,
> +	REG_GP_RMP1_BIT,
> +	REG_GP_OLED_BIT,
> +};
> +
> +struct lm3509_bl {
> +	struct regmap *regmap;
> +	struct backlight_device *bl_main;
> +	struct backlight_device *bl_sub;
> +	struct gpio_desc *reset_gpio;
> +};
> +
> +struct lm3509_bl_led_pdata {
> +	const char *label;
> +	int led_sources;
> +	u32 brightness;
> +	u32 max_brightness;
> +};
> +
> +static void lm3509_reset(struct lm3509_bl *data)
> +{
> +	if (data->reset_gpio) {
> +		gpiod_set_value(data->reset_gpio, 1);
> +		udelay(1);
> +		gpiod_set_value(data->reset_gpio, 0);
> +		udelay(10);
> +	}
> +}
> +
> +static int lm3509_update_status(struct backlight_device *bl,
> +				unsigned int en_mask, unsigned int br_reg)
> +{
> +	struct lm3509_bl *data = bl_get_data(bl);
> +	int ret;
> +	bool en;
> +
> +	ret = regmap_write(data->regmap, br_reg, bl->props.brightness);

Here you can use backlight_get_brightness() thus avoiding direct access
to backlight internal properties.

> +	if (ret < 0)
> +		return ret;
> +
> +	en = bl->props.power <= FB_BLANK_NORMAL;
Use backlight_is_blank() here.

	Sam



> +	return regmap_update_bits(data->regmap, REG_GP, en_mask,
> +				  en ? en_mask : 0);
> +}
> +
> +static int lm3509_main_update_status(struct backlight_device *bl)
> +{
> +	return lm3509_update_status(bl, BIT(REG_GP_ENM_BIT), REG_BMAIN);
> +}
> +
> +static const struct backlight_ops lm3509_main_ops = {
> +	.options = BL_CORE_SUSPENDRESUME,
> +	.update_status = lm3509_main_update_status,
> +};
> +
> +static int lm3509_sub_update_status(struct backlight_device *bl)
> +{
> +	return lm3509_update_status(bl, BIT(REG_GP_ENS_BIT), REG_BSUB);
> +}
> +
> +static const struct backlight_ops lm3509_sub_ops = {
> +	.options = BL_CORE_SUSPENDRESUME,
> +	.update_status = lm3509_sub_update_status,
> +};
> +
> +static struct backlight_device *
> +lm3509_backlight_register(struct device *dev, const char *name_suffix,
> +			  struct lm3509_bl *data,
> +			  const struct backlight_ops *ops,
> +			  const struct lm3509_bl_led_pdata *pdata)
> +
> +{
> +	struct backlight_device *bd;
> +	struct backlight_properties props;
> +	const char *label = pdata->label;
> +	char name[64];
> +
> +	memset(&props, 0, sizeof(props));
> +	props.type = BACKLIGHT_RAW;
> +	props.brightness = pdata->brightness;
> +	props.max_brightness = pdata->max_brightness;
> +	props.power = pdata->brightness > 0 ? FB_BLANK_UNBLANK :
> +					      FB_BLANK_POWERDOWN;
props.power is not supposed to be set by the user - is is maintained by
the backlight core.


	Sam