[PATCH v2 0/4] backlight: add new max25014 backlight driver

[PATCH v2 0/4] backlight: add new max25014 backlight driver

[Maud Spierings via B4 Relay]

The Maxim MAX25014 is an automotive grade backlight driver IC. Its
datasheet can be found at [1].

With its integrated boost controller, it can power 4 channels (led
strings) and has a number of different modes using pwm and or i2c.
Currently implemented is only i2c control.

link: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX25014.pdf [1]

Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
---
Changes in v2:
- Remove leftover unused property from the bindings example
- Complete the bindings example with all properties
- Remove some double info from the maxim,iset property
- Remove platform_data header, fold its data into the max25014 struct
- Don't force defines to be unsigned
- Remove stray struct max25014 declaration
- Remove chipname and device from the max25014 struct
- Inline the max25014_backlight_register() and strings_mask() functions
- Remove CONFIG_OF ifdef
- Link to v1: https://lore.kernel.org/r/20250725-max25014-v1-0-0e8cce92078e@gocontroll.com

---
Maud Spierings (4):
      dt-bindings: backlight: Add max25014 bindings
      backlight: add max25014atg backlight
      arm64: dts: freescale: moduline-display-av101hdt-a10: add backlight
      arm64: dts: freescale: moduline-display-av123z7m-n17: add backlight

 .../bindings/leds/backlight/maxim,max25014.yaml    |  79 +++++
 MAINTAINERS                                        |   6 +
 ...x8p-ml81-moduline-display-106-av101hdt-a10.dtso |  21 ++
 ...x8p-ml81-moduline-display-106-av123z7m-n17.dtso |  19 +-
 drivers/video/backlight/Kconfig                    |   7 +
 drivers/video/backlight/Makefile                   |   1 +
 drivers/video/backlight/max25014.c                 | 395 +++++++++++++++++++++
 7 files changed, 527 insertions(+), 1 deletion(-)
---
base-commit: 886e5e7b0432360842303d587bb4a65d10741ae8
change-id: 20250626-max25014-4207591e1af5

Best regards,
-- 
Maud Spierings <maudspierings@gocontroll.com>

[PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Maud Spierings via B4 Relay]

From: Maud Spierings <maudspierings@gocontroll.com>

The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
with intgrated boost controller.

Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
---
 .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
 MAINTAINERS                                        |  5 ++
 2 files changed, 84 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..30b591152fa31d5e43243cac44c72028b05b5f8a
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim max25014 backlight controller
+
+maintainers:
+  - Maud Spierings <maudspierings@gocontroll.com>
+
+allOf:
+  - $ref: common.yaml#
+
+properties:
+  compatible:
+    enum:
+      - maxim,max25014
+
+  reg:
+    maxItems: 1
+
+  enable-gpios:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  power-supply:
+    description: Regulator which controls the boost converter input rail.
+
+  pwms:
+    maxItems: 1
+
+  maxim,iset:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 11
+    description:
+      Value of the ISET register field (0-15).
+
+  maxim,strings:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+      A 4-bit bitfield that describes which led strings to turn on.
+    minItems: 4
+    maxItems: 4
+
+required:
+  - compatible
+  - reg
+  - maxim,strings
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        backlight: backlight@6f {
+            reg = <0x6f>;
+            compatible = "maxim,max25014";
+            default-brightness = <50>;
+            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
+            pinctrl-names = "default";
+            pinctrl-0 = <&pinctrl_backlight>;
+            power-supply = <&reg_backlight>;
+            pwms = <&pwm1>;
+            maxim,iset = <7>;
+            maxim,strings = <1 1 1 1>;
+        };
+    };
+
diff --git a/MAINTAINERS b/MAINTAINERS
index e81d5f9fbd16cc384356804390d65652bbb9e3f6..11c73d2e37fac22aea852152746236c1472f41b8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14972,6 +14972,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
 F:	drivers/media/i2c/max2175*
 F:	include/uapi/linux/max2175.h
 
+MAX25014 BACKLIGHT DRIVER
+M:	Maud Spierings <maudspierings@gocontroll.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
+
 MAX31335 RTC DRIVER
 M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
 L:	linux-rtc@vger.kernel.org

-- 
2.50.1

[PATCH v2 2/4] backlight: add max25014atg backlight

[Maud Spierings via B4 Relay]

From: Maud Spierings <maudspierings@gocontroll.com>

The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
with intgrated boost controller.

Signed-off-by: Maud Spierings maudspierings@gocontroll.com
---
 MAINTAINERS                        |   1 +
 drivers/video/backlight/Kconfig    |   7 +
 drivers/video/backlight/Makefile   |   1 +
 drivers/video/backlight/max25014.c | 395 +++++++++++++++++++++++++++++++++++++
 4 files changed, 404 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 11c73d2e37fac22aea852152746236c1472f41b8..d5b75af7e776e7e30e057eea5b49bb8a266e4963 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14976,6 +14976,7 @@ MAX25014 BACKLIGHT DRIVER
 M:	Maud Spierings <maudspierings@gocontroll.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
+F:	drivers/video/backlight/max25014.c
 
 MAX31335 RTC DRIVER
 M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index d9374d208ceebbf8b3c27976e9cb4d725939b942..d3bb6ccd41853d940f24c6ab8135e4b9b9ebefd7 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -262,6 +262,13 @@ config BACKLIGHT_DA9052
 	help
 	  Enable the Backlight Driver for DA9052-BC and DA9053-AA/Bx PMICs.
 
+config BACKLIGHT_MAX25014
+	tristate "Backlight driver for the Maxim MAX25014 chip"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you are using a MAX25014 chip as a backlight driver say Y to enable it.
+
 config BACKLIGHT_MAX8925
 	tristate "Backlight driver for MAX8925"
 	depends on MFD_MAX8925
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index dfbb169bf6ea215704859f633b6c4a887f4ebacd..1170d9ec40b8dbd52aeec1dade1cd2d2b56af466 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_BACKLIGHT_LOCOMO)		+= locomolcd.o
 obj-$(CONFIG_BACKLIGHT_LP855X)		+= lp855x_bl.o
 obj-$(CONFIG_BACKLIGHT_LP8788)		+= lp8788_bl.o
 obj-$(CONFIG_BACKLIGHT_LV5207LP)	+= lv5207lp.o
+obj-$(CONFIG_BACKLIGHT_MAX25014)	+= max25014.o
 obj-$(CONFIG_BACKLIGHT_MAX8925)		+= max8925_bl.o
 obj-$(CONFIG_BACKLIGHT_MP3309C)		+= mp3309c.o
 obj-$(CONFIG_BACKLIGHT_MT6370)		+= mt6370-backlight.o
diff --git a/drivers/video/backlight/max25014.c b/drivers/video/backlight/max25014.c
new file mode 100644
index 0000000000000000000000000000000000000000..fe5e0615cf6d151868b56ebb9544b175b09dfcee
--- /dev/null
+++ b/drivers/video/backlight/max25014.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Backlight driver for Maxim MAX25014
+ *
+ * Copyright (C) 2025 GOcontroll B.V.
+ * Author: Maud Spierings <maudspierings@gocontroll.com>
+ */
+
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define MAX25014_ISET_DEFAULT_100 11
+#define MAX_BRIGHTNESS (100)
+#define MIN_BRIGHTNESS (0)
+#define TON_MAX (130720) /* @153Hz */
+#define TON_STEP (1307) /* @153Hz */
+#define TON_MIN (0)
+
+#define MAX25014_DEV_ID         (0x00)
+#define MAX25014_REV_ID         (0x01)
+#define MAX25014_ISET           (0x02)
+#define MAX25014_IMODE          (0x03)
+#define MAX25014_TON1H          (0x04)
+#define MAX25014_TON1L          (0x05)
+#define MAX25014_TON2H          (0x06)
+#define MAX25014_TON2L          (0x07)
+#define MAX25014_TON3H          (0x08)
+#define MAX25014_TON3L          (0x09)
+#define MAX25014_TON4H          (0x0A)
+#define MAX25014_TON4L          (0x0B)
+#define MAX25014_TON_1_4_LSB    (0x0C)
+#define MAX25014_SETTING        (0x12)
+#define MAX25014_DISABLE        (0x13)
+#define MAX25014_BSTMON         (0x14)
+#define MAX25014_IOUT1          (0x15)
+#define MAX25014_IOUT2          (0x16)
+#define MAX25014_IOUT3          (0x17)
+#define MAX25014_IOUT4          (0x18)
+#define MAX25014_OPEN           (0x1B)
+#define MAX25014_SHORT_GND      (0x1C)
+#define MAX25014_SHORT_LED      (0x1D)
+#define MAX25014_MASK           (0x1E)
+#define MAX25014_DIAG           (0x1F)
+
+#define MAX25014_IMODE_HDIM     BIT(2)
+#define MAX25014_ISET_ENABLE    BIT(5)
+#define MAX25014_ISET_PSEN      BIT(4)
+#define MAX25014_DIAG_HW_RST    BIT(2)
+#define MAX25014_SETTING_FPWM   GENMASK(6, 4)
+
+struct max25014 {
+	struct i2c_client *client;
+	struct backlight_device *bl;
+	struct regmap *regmap;
+	struct max25014_platform_data *pdata;
+	struct gpio_desc *enable;
+	struct regulator *vin; /* regulator for boost converter Vin rail */
+	uint32_t initial_brightness;
+	uint32_t iset;
+	uint8_t strings_mask;
+};
+
+static const struct regmap_config max25014_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX25014_DIAG,
+};
+
+/**
+ * @brief control the brightness with i2c registers
+ *
+ * @param regmap trivial
+ * @param brt brightness
+ * @return int
+ */
+static int max25014_register_control(struct regmap *regmap, uint32_t brt)
+{
+	uint32_t reg = TON_STEP * brt;
+	int ret;
+	/*
+	 * 18 bit number lowest, 2 bits in first register,
+	 * next lowest 8 in the L register, next 8 in the H register
+	 * Seemingly setting the strength of only one string controls all of
+	 * them, individual settings don't affect the outcome.
+	 */
+
+	ret = regmap_write(regmap, MAX25014_TON_1_4_LSB, reg & 0b00000011);
+	if (ret != 0)
+		return ret;
+	ret = regmap_write(regmap, MAX25014_TON1L, (reg >> 2) & 0b11111111);
+	if (ret != 0)
+		return ret;
+	return regmap_write(regmap, MAX25014_TON1H, (reg >> 10) & 0b11111111);
+}
+
+static int max25014_check_errors(struct max25014 *maxim)
+{
+	uint8_t i;
+	int ret;
+	uint32_t val;
+
+	ret = regmap_read(maxim->regmap, MAX25014_OPEN, &val);
+	if (ret != 0)
+		return ret;
+	if (val > 0) {
+		dev_err(&maxim->client->dev, "Open led strings detected on:\n");
+		for (i = 0; i < 4; i++) {
+			if (val & 1 << i)
+				dev_err(&maxim->client->dev, "string %d\n", i + 1);
+		}
+		return -EIO;
+	}
+
+	ret = regmap_read(maxim->regmap, MAX25014_SHORT_GND, &val);
+	if (ret != 0)
+		return ret;
+	if (val > 0) {
+		dev_err(&maxim->client->dev, "Short to ground detected on:\n");
+		for (i = 0; i < 4; i++) {
+			if (val & 1 << i)
+				dev_err(&maxim->client->dev, "string %d\n", i + 1);
+		}
+		return -EIO;
+	}
+
+	ret = regmap_read(maxim->regmap, MAX25014_SHORT_GND, &val);
+	if (ret != 0)
+		return ret;
+	if (val > 0) {
+		dev_err(&maxim->client->dev, "Shorted led detected on:\n");
+		for (i = 0; i < 4; i++) {
+			if (val & 1 << i)
+				dev_err(&maxim->client->dev, "string %d\n", i + 1);
+		}
+		return -EIO;
+	}
+
+	ret = regmap_read(maxim->regmap, MAX25014_DIAG, &val);
+	if (ret != 0)
+		return ret;
+	/*
+	 * The HW_RST bit always starts at 1 after power up.
+	 * It is reset on first read, does not indicate an error.
+	 */
+	if (val > 0 && val != MAX25014_DIAG_HW_RST) {
+		if (val & 0b1)
+			dev_err(&maxim->client->dev, "Overtemperature shutdown\n");
+		if (val & 0b10)
+			dev_warn(&maxim->client->dev,
+				 "Chip is getting too hot (>125C)\n");
+		if (val & 0b1000)
+			dev_err(&maxim->client->dev, "Boost converter overvoltage\n");
+		if (val & 0b10000)
+			dev_err(&maxim->client->dev, "Boost converter undervoltage\n");
+		if (val & 0b100000)
+			dev_err(&maxim->client->dev, "IREF out of range\n");
+		return -EIO;
+	}
+	return 0;
+}
+
+/*
+ * 1. disable unused strings
+ * 2. set dim mode
+ * 3. set initial brightness
+ * 4. set setting register
+ * 5. enable the backlight
+ */
+static int max25014_configure(struct max25014 *maxim)
+{
+	int ret;
+	uint32_t val;
+
+	ret = regmap_write(maxim->regmap, MAX25014_DISABLE,
+			   maxim->strings_mask);
+	if (ret != 0)
+		return ret;
+
+	ret = regmap_write(maxim->regmap, MAX25014_IMODE, MAX25014_IMODE_HDIM);
+	if (ret != 0)
+		return ret;
+
+	max25014_register_control(maxim->regmap,
+				  maxim->initial_brightness);
+
+	ret = regmap_read(maxim->regmap, MAX25014_SETTING, &val);
+	if (ret != 0)
+		return ret;
+
+	ret = regmap_write(
+		maxim->regmap, MAX25014_SETTING,
+		val & ~MAX25014_SETTING_FPWM);
+	if (ret != 0)
+		return ret;
+
+	ret = regmap_write(maxim->regmap, MAX25014_ISET,
+			   maxim->iset | MAX25014_ISET_ENABLE | MAX25014_ISET_PSEN);
+	return ret;
+}
+
+static int max25014_update_status(struct backlight_device *bl_dev)
+{
+	struct max25014 *maxim = bl_get_data(bl_dev);
+
+	if (bl_dev->props.state & BL_CORE_SUSPENDED)
+		bl_dev->props.brightness = 0;
+
+	return max25014_register_control(maxim->regmap, bl_dev->props.brightness);
+}
+
+static const struct backlight_ops max25014_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = max25014_update_status,
+};
+
+static int max25014_parse_dt(struct max25014 *maxim)
+{
+	struct device *dev = &maxim->client->dev;
+	struct device_node *node = dev->of_node;
+	uint32_t strings[4];
+	int res, i;
+
+	if (!node) {
+		dev_err(dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	res = of_property_count_u32_elems(node, "maxim,strings");
+	if (res == 4) {
+		of_property_read_u32_array(node, "maxim,strings", strings, 4);
+	} else {
+		dev_err(dev, "strings property not correctly defined\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < 4; i++) {
+		if (strings[i] == 0)
+			maxim->strings_mask |= 1 << i;
+	}
+
+	maxim->initial_brightness = 50U;
+	of_property_read_u32(node, "default-brightness", &maxim->initial_brightness);
+	maxim->iset = MAX25014_ISET_DEFAULT_100;
+	of_property_read_u32(node, "maxim,iset", &maxim->iset);
+
+	if (maxim->iset < 0 || maxim->iset > 15) {
+		dev_err(dev,
+			"Invalid iset, should be a value from 0-15, entered was %d\n",
+			maxim->iset);
+		return -EINVAL;
+	}
+
+	if (maxim->initial_brightness < 0 || maxim->initial_brightness > 100) {
+		dev_err(dev,
+			"Invalid initial brightness, should be a value from 0-100, entered was %d\n",
+			maxim->initial_brightness);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int max25014_probe(struct i2c_client *cl)
+{
+	struct backlight_device *bl;
+	const struct i2c_device_id *id = i2c_client_get_device_id(cl);
+	struct max25014 *maxim;
+	struct backlight_properties props;
+	int ret;
+
+	maxim = devm_kzalloc(&cl->dev, sizeof(struct max25014), GFP_KERNEL);
+	if (!maxim)
+		return -ENOMEM;
+
+	maxim->client = cl;
+
+	ret = max25014_parse_dt(maxim);
+	if (ret < 0)
+		return ret;
+
+	maxim->vin = devm_regulator_get(&maxim->client->dev, "power");
+	if (IS_ERR(maxim->vin)) {
+		if (PTR_ERR(maxim->vin) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		maxim->vin = NULL;
+	}
+
+	if (maxim->vin) {
+		ret = regulator_enable(maxim->vin);
+		if (ret < 0) {
+			dev_err(&maxim->client->dev, "failed to enable Vin: %d\n", ret);
+			return ret;
+		}
+	}
+
+	maxim->enable =
+		devm_gpiod_get_optional(&maxim->client->dev, "enable", GPIOD_ASIS);
+	if (IS_ERR(maxim->enable)) {
+		ret = PTR_ERR(maxim->enable);
+		dev_err(&maxim->client->dev, "failed to get enable gpio: %d\n", ret);
+		goto disable_vin;
+	}
+
+	if (maxim->enable) {
+		gpiod_set_value_cansleep(maxim->enable, 1);
+
+		/* Datasheet Electrical Characteristics tSTARTUP 2ms */
+		usleep_range(2000, 2500);
+	}
+
+	maxim->regmap = devm_regmap_init_i2c(cl, &max25014_regmap_config);
+	if (IS_ERR(maxim->regmap)) {
+		ret = PTR_ERR(maxim->regmap);
+		dev_err(&maxim->client->dev, "failed to initialize the i2c regmap: %d\n", ret);
+		goto disable_full;
+	}
+
+	i2c_set_clientdata(cl, maxim);
+
+	ret = max25014_check_errors(maxim);
+	if (ret) { /* error is already reported in the above function */
+		goto disable_full;
+	}
+
+	ret = max25014_configure(maxim);
+	if (ret) {
+		dev_err(&maxim->client->dev, "device config err: %d", ret);
+		goto disable_full;
+	}
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_PLATFORM;
+	props.max_brightness = MAX_BRIGHTNESS;
+
+	props.brightness = maxim->initial_brightness;
+
+	bl = devm_backlight_device_register(&maxim->client->dev, id->name, &maxim->client->dev,
+					    maxim, &max25014_bl_ops, &props);
+	if (IS_ERR(bl))
+		return PTR_ERR(bl);
+
+	maxim->bl = bl;
+
+	return 0;
+
+disable_full:
+	if (maxim->enable)
+		gpiod_set_value_cansleep(maxim->enable, 0);
+disable_vin:
+	if (maxim->vin)
+		regulator_disable(maxim->vin);
+	return ret;
+}
+
+static void max25014_remove(struct i2c_client *cl)
+{
+	struct max25014 *maxim = i2c_get_clientdata(cl);
+
+	maxim->bl->props.brightness = 0;
+	max25014_update_status(maxim->bl);
+	if (maxim->enable)
+		gpiod_set_value_cansleep(maxim->enable, 0);
+	if (maxim->vin)
+		regulator_disable(maxim->vin);
+}
+
+static const struct of_device_id max25014_dt_ids[] = {
+	{ .compatible = "maxim,max25014", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max25014_dt_ids);
+
+static const struct i2c_device_id max25014_ids[] = {
+	{ "max25014" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max25014_ids);
+
+static struct i2c_driver max25014_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = of_match_ptr(max25014_dt_ids),
+	},
+	.probe = max25014_probe,
+	.remove = max25014_remove,
+	.id_table = max25014_ids,
+};
+module_i2c_driver(max25014_driver);
+
+MODULE_DESCRIPTION("Maxim MAX25014 backlight driver");
+MODULE_AUTHOR("Maud Spierings <maudspierings@gocontroll.com>");
+MODULE_LICENSE("GPL");

-- 
2.50.1

[PATCH v2 3/4] arm64: dts: freescale: moduline-display-av101hdt-a10: add backlight

[Maud Spierings via B4 Relay]

From: Maud Spierings <maudspierings@gocontroll.com>

Add the missing backlight driver.

Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
---
 ...tx8p-ml81-moduline-display-106-av101hdt-a10.dtso | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av101hdt-a10.dtso b/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av101hdt-a10.dtso
index e3965caca6be42a17aa89b77bd5b919382c84151..143243ba95cd7a69c7b043fa0fb32c37b67e1064 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av101hdt-a10.dtso
+++ b/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av101hdt-a10.dtso
@@ -17,6 +17,7 @@
 
 	panel {
 		compatible = "boe,av101hdt-a10";
+		backlight = <&backlight>;
 		enable-gpios = <&gpio1 7 GPIO_ACTIVE_HIGH>;
 		pinctrl-0 = <&pinctrl_panel>;
 		pinctrl-names = "default";
@@ -40,7 +41,27 @@ reg_vbus: regulator-vbus {
 	};
 };
 
+&i2c4 {
+	backlight: backlight@6f {
+		reg = <0x6f>;
+		compatible = "maxim,max25014";
+		default-brightness = <50>;
+		enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_backlight>;
+		maxim,iset = <7>;
+		maxim,strings = <1 1 1 0>;
+	};
+};
+
 &iomuxc {
+	pinctrl_backlight: backlightgrp {
+		fsl,pins = <
+			MX8MP_IOMUXC_GPIO1_IO04__GPIO1_IO04
+				(MX8MP_PULL_UP | MX8MP_PULL_ENABLE)
+		>;
+	};
+
 	pinctrl_panel: panelgrp {
 		fsl,pins = <
 			MX8MP_IOMUXC_GPIO1_IO07__GPIO1_IO07

-- 
2.50.1

[PATCH v2 4/4] arm64: dts: freescale: moduline-display-av123z7m-n17: add backlight

[Maud Spierings via B4 Relay]

From: Maud Spierings <maudspierings@gocontroll.com>

Add the missing backlight.

Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
---
 ...p-tx8p-ml81-moduline-display-106-av123z7m-n17.dtso | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av123z7m-n17.dtso b/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av123z7m-n17.dtso
index 3eb665ce9d5d2a1c742ffb4feca046e406e29956..9124cd87cce54a5aa7b7ad674f70f814d1dc3515 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av123z7m-n17.dtso
+++ b/arch/arm64/boot/dts/freescale/imx8mp-tx8p-ml81-moduline-display-106-av123z7m-n17.dtso
@@ -16,6 +16,7 @@
 
 	panel {
 		compatible = "boe,av123z7m-n17";
+		backlight = <&backlight>;
 		enable-gpios = <&gpio1 7 GPIO_ACTIVE_HIGH>;
 		pinctrl-0 = <&pinctrl_panel>;
 		pinctrl-names = "default";
@@ -91,10 +92,26 @@ lvds1_out: endpoint {
 		};
 	};
 
-	/* max25014 @ 0x6f */
+	backlight: backlight@6f {
+		reg = <0x6f>;
+		compatible = "maxim,max25014";
+		default-brightness = <50>;
+		enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_backlight>;
+		maxim,iset = <7>;
+		maxim,strings = <1 1 1 1>;
+	};
 };
 
 &iomuxc {
+	pinctrl_backlight: backlightgrp {
+		fsl,pins = <
+			MX8MP_IOMUXC_GPIO1_IO04__GPIO1_IO04
+				(MX8MP_PULL_UP | MX8MP_PULL_ENABLE)
+		>;
+	};
+
 	pinctrl_lvds_bridge: lvdsbridgegrp {
 		fsl,pins = <
 			MX8MP_IOMUXC_SAI1_TXD2__GPIO4_IO14

-- 
2.50.1

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Fabio Estevam]

On Tue, Aug 19, 2025 at 7:59 AM Maud Spierings via B4 Relay
<devnull+maudspierings.gocontroll.com@kernel.org> wrote:
>
> From: Maud Spierings <maudspierings@gocontroll.com>
>
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with intgrated boost controller.

Typo: integrated

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Rob Herring (Arm)]

On Tue, 19 Aug 2025 12:58:59 +0200, Maud Spierings wrote:
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with intgrated boost controller.
> 
> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> ---
>  .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
>  MAINTAINERS                                        |  5 ++
>  2 files changed, 84 insertions(+)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:


doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250819-max25014-v2-1-5fd7aeb141ea@gocontroll.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Maud Spierings]

On 8/19/25 14:28, Fabio Estevam wrote:
> On Tue, Aug 19, 2025 at 7:59 AM Maud Spierings via B4 Relay
> <devnull+maudspierings.gocontroll.com@kernel.org> wrote:
>>
>> From: Maud Spierings <maudspierings@gocontroll.com>
>>
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with intgrated boost controller.
> 
> Typo: integrated

oopsie fixed, ctrl+c ctrl+v in patch 2 fixed too

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Rob Herring]

On Tue, Aug 19, 2025 at 12:58:59PM +0200, Maud Spierings wrote:
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with intgrated boost controller.
> 
> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> ---
>  .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
>  MAINTAINERS                                        |  5 ++
>  2 files changed, 84 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..30b591152fa31d5e43243cac44c72028b05b5f8a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> @@ -0,0 +1,79 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim max25014 backlight controller
> +
> +maintainers:
> +  - Maud Spierings <maudspierings@gocontroll.com>
> +
> +allOf:
> +  - $ref: common.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - maxim,max25014
> +
> +  reg:
> +    maxItems: 1
> +
> +  enable-gpios:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  power-supply:
> +    description: Regulator which controls the boost converter input rail.
> +
> +  pwms:
> +    maxItems: 1
> +
> +  maxim,iset:
> +    $ref: /schemas/types.yaml#/definitions/uint32

       maximum: 15

> +    default: 11
> +    description:
> +      Value of the ISET register field (0-15).

Perhaps a little on what this controls? 

> +
> +  maxim,strings:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    description:
> +      A 4-bit bitfield that describes which led strings to turn on.
> +    minItems: 4
> +    maxItems: 4

       items:
         maximum: 1

But why not just an 8-bit value 0x0-0xF?

> +
> +required:
> +  - compatible
> +  - reg
> +  - maxim,strings
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        backlight: backlight@6f {

Drop unused labels.

> +            reg = <0x6f>;
> +            compatible = "maxim,max25014";

compatible is always first.

> +            default-brightness = <50>;
> +            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
> +            interrupt-parent = <&gpio1>;
> +            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
> +            pinctrl-names = "default";
> +            pinctrl-0 = <&pinctrl_backlight>;

Generally we don't put pinctrl properties in examples as they are always 
allowed.

> +            power-supply = <&reg_backlight>;
> +            pwms = <&pwm1>;
> +            maxim,iset = <7>;
> +            maxim,strings = <1 1 1 1>;
> +        };
> +    };
> +
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e81d5f9fbd16cc384356804390d65652bbb9e3f6..11c73d2e37fac22aea852152746236c1472f41b8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14972,6 +14972,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
>  F:	drivers/media/i2c/max2175*
>  F:	include/uapi/linux/max2175.h
>  
> +MAX25014 BACKLIGHT DRIVER
> +M:	Maud Spierings <maudspierings@gocontroll.com>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> +
>  MAX31335 RTC DRIVER
>  M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
>  L:	linux-rtc@vger.kernel.org
> 
> -- 
> 2.50.1
> 

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Maud Spierings]

On 8/19/25 21:50, Rob Herring wrote:
> On Tue, Aug 19, 2025 at 12:58:59PM +0200, Maud Spierings wrote:
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with intgrated boost controller.
>>
>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>> ---
>>   .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
>>   MAINTAINERS                                        |  5 ++
>>   2 files changed, 84 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..30b591152fa31d5e43243cac44c72028b05b5f8a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Maxim max25014 backlight controller
>> +
>> +maintainers:
>> +  - Maud Spierings <maudspierings@gocontroll.com>
>> +
>> +allOf:
>> +  - $ref: common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - maxim,max25014
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  power-supply:
>> +    description: Regulator which controls the boost converter input rail.
>> +
>> +  pwms:
>> +    maxItems: 1
>> +
>> +  maxim,iset:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
> 
>         maximum: 15

done
>> +    default: 11
>> +    description:
>> +      Value of the ISET register field (0-15).
> 
> Perhaps a little on what this controls?

done, for now, it controls the current scale of the backlight, higher 
number = more current. But I will put it in the description in v3

>> +
>> +  maxim,strings:
>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>> +    description:
>> +      A 4-bit bitfield that describes which led strings to turn on.
>> +    minItems: 4
>> +    maxItems: 4
> 
>         items:
>           maximum: 1
> 
> But why not just an 8-bit value 0x0-0xF?

That is possible too, the logic is inverted in the actual chip, a bit 
set means the string is turned off, but that can be solved with a 
bitwise not. This just felt like a natural way to read/edit it, an 8-bit 
value you have to first translate the bits into a hex value which isn't 
very clear about what it is actually doing.

Is it possible to to 0b0111 notation in a devicetree? That would make it 
better at least.

>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - maxim,strings
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +    #include <dt-bindings/interrupt-controller/irq.h>
>> +
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        backlight: backlight@6f {
> 
> Drop unused labels.

oops dropped

>> +            reg = <0x6f>;
>> +            compatible = "maxim,max25014";
> 
> compatible is always first.

Messed that up in the dtsos too, fixed everywhere in v3

>> +            default-brightness = <50>;
>> +            enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
>> +            interrupt-parent = <&gpio1>;
>> +            interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
>> +            pinctrl-names = "default";
>> +            pinctrl-0 = <&pinctrl_backlight>;
> 
> Generally we don't put pinctrl properties in examples as they are always
> allowed.

dropped

>> +            power-supply = <&reg_backlight>;
>> +            pwms = <&pwm1>;
>> +            maxim,iset = <7>;
>> +            maxim,strings = <1 1 1 1>;
>> +        };
>> +    };
>> +
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index e81d5f9fbd16cc384356804390d65652bbb9e3f6..11c73d2e37fac22aea852152746236c1472f41b8 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -14972,6 +14972,11 @@ F:	Documentation/userspace-api/media/drivers/max2175.rst
>>   F:	drivers/media/i2c/max2175*
>>   F:	include/uapi/linux/max2175.h
>>   
>> +MAX25014 BACKLIGHT DRIVER
>> +M:	Maud Spierings <maudspierings@gocontroll.com>
>> +S:	Maintained
>> +F:	Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> +
>>   MAX31335 RTC DRIVER
>>   M:	Antoniu Miclaus <antoniu.miclaus@analog.com>
>>   L:	linux-rtc@vger.kernel.org
>>
>> -- 
>> 2.50.1
>>

Thanks for your review!
Kind regards,
Maud

Re: [PATCH v2 2/4] backlight: add max25014atg backlight

[Daniel Thompson]

On Tue, Aug 19, 2025 at 12:59:00PM +0200, Maud Spierings via B4 Relay wrote:
> From: Maud Spierings <maudspierings@gocontroll.com>
>
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with intgrated boost controller.
>
> Signed-off-by: Maud Spierings maudspierings@gocontroll.com

Looking good but still a few small comments (below).


> diff --git a/drivers/video/backlight/max25014.c b/drivers/video/backlight/max25014.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..fe5e0615cf6d151868b56ebb9544b175b09dfcee
> --- /dev/null
> +++ b/drivers/video/backlight/max25014.c
> @@ -0,0 +1,395 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Backlight driver for Maxim MAX25014
> + *
> + * Copyright (C) 2025 GOcontroll B.V.
> + * Author: Maud Spierings <maudspierings@gocontroll.com>
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#define MAX25014_ISET_DEFAULT_100 11
> +#define MAX_BRIGHTNESS (100)
> +#define MIN_BRIGHTNESS (0)
> +#define TON_MAX (130720) /* @153Hz */
> +#define TON_STEP (1307) /* @153Hz */
> +#define TON_MIN (0)
> +
> +#define MAX25014_DEV_ID         (0x00)
> +#define MAX25014_REV_ID         (0x01)
> +#define MAX25014_ISET           (0x02)
> +#define MAX25014_IMODE          (0x03)
> +#define MAX25014_TON1H          (0x04)
> +#define MAX25014_TON1L          (0x05)
> +#define MAX25014_TON2H          (0x06)
> +#define MAX25014_TON2L          (0x07)
> +#define MAX25014_TON3H          (0x08)
> +#define MAX25014_TON3L          (0x09)
> +#define MAX25014_TON4H          (0x0A)
> +#define MAX25014_TON4L          (0x0B)
> +#define MAX25014_TON_1_4_LSB    (0x0C)
> +#define MAX25014_SETTING        (0x12)
> +#define MAX25014_DISABLE        (0x13)
> +#define MAX25014_BSTMON         (0x14)
> +#define MAX25014_IOUT1          (0x15)
> +#define MAX25014_IOUT2          (0x16)
> +#define MAX25014_IOUT3          (0x17)
> +#define MAX25014_IOUT4          (0x18)
> +#define MAX25014_OPEN           (0x1B)
> +#define MAX25014_SHORT_GND      (0x1C)
> +#define MAX25014_SHORT_LED      (0x1D)
> +#define MAX25014_MASK           (0x1E)
> +#define MAX25014_DIAG           (0x1F)

There is no need to put raw numbers in brackets.


> +
> +#define MAX25014_IMODE_HDIM     BIT(2)
> +#define MAX25014_ISET_ENABLE    BIT(5)
> +#define MAX25014_ISET_PSEN      BIT(4)
> +#define MAX25014_DIAG_HW_RST    BIT(2)
> +#define MAX25014_SETTING_FPWM   GENMASK(6, 4)
> +
> +struct max25014 {
> +	struct i2c_client *client;
> +	struct backlight_device *bl;
> +	struct regmap *regmap;
> +	struct max25014_platform_data *pdata;

This appears to be unused.


> +	struct gpio_desc *enable;
> +	struct regulator *vin; /* regulator for boost converter Vin rail */
> +	uint32_t initial_brightness;

It is important to keep the initial_brightness for the lifetime of the
driver?

> +	uint32_t iset;
> +	uint8_t strings_mask;
> +};
> +


Daniel.

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Daniel Thompson]

On Tue, Aug 19, 2025 at 12:58:59PM +0200, Maud Spierings via B4 Relay wrote:
> From: Maud Spierings <maudspierings@gocontroll.com>
>
> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
> with intgrated boost controller.
>
> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
> ---
>  .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
>  MAINTAINERS                                        |  5 ++
>  2 files changed, 84 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..30b591152fa31d5e43243cac44c72028b05b5f8a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
> @@ -0,0 +1,79 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Maxim max25014 backlight controller
> +
> +maintainers:
> +  - Maud Spierings <maudspierings@gocontroll.com>
> +
> +allOf:
> +  - $ref: common.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - maxim,max25014
> +
> +  reg:
> +    maxItems: 1
> +
> +  enable-gpios:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1

Is the interrupt useful for anything?

AFAIK its perfectly OK for DT bindings to describe hardware features the
driver does not use... but is the driver missing out on error reporting
(for example) by not using this interrupt for anything?


Daniel.

Re: [PATCH v2 2/4] backlight: add max25014atg backlight

[Maud Spierings]

Hi Daniel,
Thanks for the review!

On 8/22/25 09:20, Daniel Thompson wrote:
> On Tue, Aug 19, 2025 at 12:59:00PM +0200, Maud Spierings via B4 Relay wrote:
>> From: Maud Spierings <maudspierings@gocontroll.com>
>>
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with intgrated boost controller.
>>
>> Signed-off-by: Maud Spierings maudspierings@gocontroll.com
> 
> Looking good but still a few small comments (below).
> 
> 
>> diff --git a/drivers/video/backlight/max25014.c b/drivers/video/backlight/max25014.c
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..fe5e0615cf6d151868b56ebb9544b175b09dfcee
>> --- /dev/null
>> +++ b/drivers/video/backlight/max25014.c
>> @@ -0,0 +1,395 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Backlight driver for Maxim MAX25014
>> + *
>> + * Copyright (C) 2025 GOcontroll B.V.
>> + * Author: Maud Spierings <maudspierings@gocontroll.com>
>> + */
>> +
>> +#include <linux/backlight.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +
>> +#define MAX25014_ISET_DEFAULT_100 11
>> +#define MAX_BRIGHTNESS (100)
>> +#define MIN_BRIGHTNESS (0)
>> +#define TON_MAX (130720) /* @153Hz */
>> +#define TON_STEP (1307) /* @153Hz */
>> +#define TON_MIN (0)
>> +
>> +#define MAX25014_DEV_ID         (0x00)
>> +#define MAX25014_REV_ID         (0x01)
>> +#define MAX25014_ISET           (0x02)
>> +#define MAX25014_IMODE          (0x03)
>> +#define MAX25014_TON1H          (0x04)
>> +#define MAX25014_TON1L          (0x05)
>> +#define MAX25014_TON2H          (0x06)
>> +#define MAX25014_TON2L          (0x07)
>> +#define MAX25014_TON3H          (0x08)
>> +#define MAX25014_TON3L          (0x09)
>> +#define MAX25014_TON4H          (0x0A)
>> +#define MAX25014_TON4L          (0x0B)
>> +#define MAX25014_TON_1_4_LSB    (0x0C)
>> +#define MAX25014_SETTING        (0x12)
>> +#define MAX25014_DISABLE        (0x13)
>> +#define MAX25014_BSTMON         (0x14)
>> +#define MAX25014_IOUT1          (0x15)
>> +#define MAX25014_IOUT2          (0x16)
>> +#define MAX25014_IOUT3          (0x17)
>> +#define MAX25014_IOUT4          (0x18)
>> +#define MAX25014_OPEN           (0x1B)
>> +#define MAX25014_SHORT_GND      (0x1C)
>> +#define MAX25014_SHORT_LED      (0x1D)
>> +#define MAX25014_MASK           (0x1E)
>> +#define MAX25014_DIAG           (0x1F)
> 
> There is no need to put raw numbers in brackets.

gone in the next version, I'll also align the defines at the top better.
>> +
>> +#define MAX25014_IMODE_HDIM     BIT(2)
>> +#define MAX25014_ISET_ENABLE    BIT(5)
>> +#define MAX25014_ISET_PSEN      BIT(4)
>> +#define MAX25014_DIAG_HW_RST    BIT(2)
>> +#define MAX25014_SETTING_FPWM   GENMASK(6, 4)
>> +
>> +struct max25014 {
>> +	struct i2c_client *client;
>> +	struct backlight_device *bl;
>> +	struct regmap *regmap;
>> +	struct max25014_platform_data *pdata;
> 
> This appears to be unused.

oops forgot to remove that, how did it even build with that?

>> +	struct gpio_desc *enable;
>> +	struct regulator *vin; /* regulator for boost converter Vin rail */
>> +	uint32_t initial_brightness;
> 
> It is important to keep the initial_brightness for the lifetime of the
> driver?

I guess not, though I am not sure how to comfortably transport this 
value to the max25014_configure() otherwise. Some temporary value that I 
create in the probe function then pass as reference to 
max25014_parse_dt() and then to max25014_configure()?

>> +	uint32_t iset;
>> +	uint8_t strings_mask;
>> +};
>> +
> 
Kind regards,
Maud

Re: [PATCH v2 1/4] dt-bindings: backlight: Add max25014 bindings

[Maud Spierings]

On 8/22/25 09:26, Daniel Thompson wrote:
> On Tue, Aug 19, 2025 at 12:58:59PM +0200, Maud Spierings via B4 Relay wrote:
>> From: Maud Spierings <maudspierings@gocontroll.com>
>>
>> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC
>> with intgrated boost controller.
>>
>> Signed-off-by: Maud Spierings <maudspierings@gocontroll.com>
>> ---
>>   .../bindings/leds/backlight/maxim,max25014.yaml    | 79 ++++++++++++++++++++++
>>   MAINTAINERS                                        |  5 ++
>>   2 files changed, 84 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..30b591152fa31d5e43243cac44c72028b05b5f8a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/backlight/maxim,max25014.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Maxim max25014 backlight controller
>> +
>> +maintainers:
>> +  - Maud Spierings <maudspierings@gocontroll.com>
>> +
>> +allOf:
>> +  - $ref: common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - maxim,max25014
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  enable-gpios:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
> 
> Is the interrupt useful for anything?
> 
> AFAIK its perfectly OK for DT bindings to describe hardware features the
> driver does not use... but is the driver missing out on error reporting
> (for example) by not using this interrupt for anything?

The interrupt is indeed for error reporting, it is not wired up in the 
driver right now (although there is already a function for scanning the 
error registers, I am not sure how I would properly hook that up to an 
irq. This is my first driver so I thought to keep things simple for now, 
these extra functions can be added later), same with the pwms for 
example. But jeah I wanted to fully describe the hardware in the 
bindings as from what I understand that is what should be done.

Kind regards,
Maud