[RFC net-next 2/4] leds: rgb: Add IS32FL3207 controller driver

[Ahmad Byagowi <ahmadexp@gmail.com>]

Add a generic I2C driver for the Lumissil IS32FL3207 18-channel
LED controller.

Expose individual and multicolor LEDs through the LED class, use the
default 8-bit 62 kHz PWM mode, derive output current from RISET, and
enforce each output current limit with the scaling registers. Handle an
optional supply and enable GPIO and serialize controller-wide update
latches.

Signed-off-by: Ahmad Byagowi <ahmadexp@gmail.com>
---
 MAINTAINERS                        |   1 +
 drivers/leds/rgb/Kconfig           |  11 +
 drivers/leds/rgb/Makefile          |   1 +
 drivers/leds/rgb/leds-is32fl3207.c | 541 +++++++++++++++++++++++++++++
 4 files changed, 554 insertions(+)
 create mode 100644 drivers/leds/rgb/leds-is32fl3207.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ff3a93474..459dd5147 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13826,6 +13826,7 @@ M:	Ahmad Byagowi <ahmadexp@gmail.com>
 L:	linux-leds@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/leds/issi,is32fl3207.yaml
+F:	drivers/leds/rgb/leds-is32fl3207.c
 
 ISOFS FILESYSTEM
 M:	Jan Kara <jack@suse.cz>
diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
index 6e9ab5f60..c896be131 100644
--- a/drivers/leds/rgb/Kconfig
+++ b/drivers/leds/rgb/Kconfig
@@ -14,6 +14,17 @@ config LEDS_GROUP_MULTICOLOR
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-group-multicolor.
 
+config LEDS_IS32FL3207
+	tristate "LED support for ISSI IS32FL3207"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y here to include support for the Lumissil IS32FL3207
+	  18-channel I2C LED controller.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called leds-is32fl3207.
+
 config LEDS_KTD202X
 	tristate "LED support for KTD202x Chips"
 	depends on I2C
diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
index cc0f2df66..228923e8b 100644
--- a/drivers/leds/rgb/Makefile
+++ b/drivers/leds/rgb/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_LEDS_GROUP_MULTICOLOR)	+= leds-group-multicolor.o
+obj-$(CONFIG_LEDS_IS32FL3207)		+= leds-is32fl3207.o
 obj-$(CONFIG_LEDS_KTD202X)		+= leds-ktd202x.o
 obj-$(CONFIG_LEDS_LP5812)		+= leds-lp5812.o
 obj-$(CONFIG_LEDS_LP5860_CORE)		+= leds-lp5860-core.o
diff --git a/drivers/leds/rgb/leds-is32fl3207.c b/drivers/leds/rgb/leds-is32fl3207.c
new file mode 100644
index 000000000..8f0453464
--- /dev/null
+++ b/drivers/leds/rgb/leds-is32fl3207.c
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ISSI IS32FL3207 LED controller driver
+ *
+ * Copyright 2026 Ahmad Byagowi
+ */
+
+#include <linux/bitmap.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/string.h>
+
+#include <dt-bindings/leds/common.h>
+
+#define IS32FL3207_NUM_CHANNELS		18
+#define IS32FL3207_MAX_BRIGHTNESS	255
+
+#define IS32FL3207_REG_CONTROL		0x00
+#define IS32FL3207_REG_PWM_LOW(channel)	(0x01 + 2 * (channel))
+#define IS32FL3207_REG_PWM_UPDATE	0x49
+#define IS32FL3207_REG_SCALING(channel)	(0x4a + (channel))
+#define IS32FL3207_REG_GLOBAL_CURRENT	0x6e
+#define IS32FL3207_REG_RESET		0x7f
+
+#define IS32FL3207_CONTROL_ENABLE	BIT(0)
+#define IS32FL3207_GLOBAL_CURRENT_MAX	0xff
+
+/* IOUT(MAX) in microamperes = 76,500,000 / RISET in ohms. */
+#define IS32FL3207_CURRENT_NUMERATOR	76500000ULL
+
+struct is32fl3207;
+
+struct is32fl3207_led {
+	struct is32fl3207 *chip;
+	union {
+		struct led_classdev cdev;
+		struct led_classdev_mc mcdev;
+	};
+	unsigned int channel;
+};
+
+struct is32fl3207 {
+	struct device *dev;
+	struct regmap *regmap;
+	struct gpio_desc *enable_gpio;
+	struct mutex lock; /* Serializes controller register updates. */
+	unsigned long channels[BITS_TO_LONGS(IS32FL3207_NUM_CHANNELS)];
+	u32 output_max_microamp;
+	unsigned int num_leds;
+	struct is32fl3207_led leds[] __counted_by(num_leds);
+};
+
+static int is32fl3207_parse_led_properties(struct is32fl3207 *chip,
+					   struct fwnode_handle *fwnode,
+					   unsigned int *max_brightness)
+{
+	const char *default_state;
+	u32 value;
+	int ret;
+
+	if (fwnode_property_present(fwnode, "retain-state-shutdown"))
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "retain-state-shutdown is not supported for %pfw\n",
+				     fwnode);
+
+	if (fwnode_property_present(fwnode, "default-brightness"))
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "default-brightness is not supported for %pfw\n",
+				     fwnode);
+
+	if (fwnode_property_present(fwnode, "default-state")) {
+		ret = fwnode_property_read_string(fwnode, "default-state",
+						  &default_state);
+		if (ret)
+			return dev_err_probe(chip->dev, ret,
+					     "failed to read default state for %pfw\n",
+					     fwnode);
+		if (strcmp(default_state, "off"))
+			return dev_err_probe(chip->dev, -EINVAL,
+					     "default state %s is not supported for %pfw\n",
+					     default_state, fwnode);
+	}
+
+	*max_brightness = IS32FL3207_MAX_BRIGHTNESS;
+	if (!fwnode_property_present(fwnode, "max-brightness"))
+		return 0;
+
+	ret = fwnode_property_read_u32(fwnode, "max-brightness", &value);
+	if (ret)
+		return dev_err_probe(chip->dev, ret,
+				     "failed to read maximum brightness for %pfw\n",
+				     fwnode);
+	if (!value || value > IS32FL3207_MAX_BRIGHTNESS)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "invalid maximum brightness %u for %pfw\n",
+				     value, fwnode);
+
+	*max_brightness = value;
+	return 0;
+}
+
+static int is32fl3207_validate_component(struct is32fl3207 *chip,
+					 struct fwnode_handle *fwnode)
+{
+	static const char * const unsupported[] = {
+		"default-brightness",
+		"default-state",
+		"max-brightness",
+		"retain-state-shutdown",
+	};
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(unsupported); i++)
+		if (fwnode_property_present(fwnode, unsupported[i]))
+			return dev_err_probe(chip->dev, -EINVAL,
+					     "%s is not supported for component %pfw\n",
+					     unsupported[i], fwnode);
+
+	return 0;
+}
+
+static int is32fl3207_write_channels(struct is32fl3207 *chip,
+				     const struct mc_subled *subleds,
+				     unsigned int num_channels)
+{
+	unsigned int i;
+	int ret;
+
+	guard(mutex)(&chip->lock);
+
+	for (i = 0; i < num_channels; i++) {
+		ret = regmap_write(chip->regmap,
+				   IS32FL3207_REG_PWM_LOW(subleds[i].channel),
+				   subleds[i].brightness);
+		if (ret)
+			return ret;
+	}
+
+	return regmap_write(chip->regmap, IS32FL3207_REG_PWM_UPDATE, 0);
+}
+
+static int is32fl3207_brightness_set(struct led_classdev *cdev,
+				     enum led_brightness brightness)
+{
+	struct is32fl3207_led *led = container_of(cdev, struct is32fl3207_led,
+						     cdev);
+	struct mc_subled subled = {
+		.brightness = brightness,
+		.channel = led->channel,
+	};
+
+	return is32fl3207_write_channels(led->chip, &subled, 1);
+}
+
+static int is32fl3207_mc_brightness_set(struct led_classdev *cdev,
+					enum led_brightness brightness)
+{
+	struct led_classdev_mc *mcdev = lcdev_to_mccdev(cdev);
+	struct is32fl3207_led *led = container_of(mcdev, struct is32fl3207_led,
+						     mcdev);
+
+	led_mc_calc_color_components(mcdev, brightness);
+
+	return is32fl3207_write_channels(led->chip, mcdev->subled_info,
+					    mcdev->num_colors);
+}
+
+static int is32fl3207_configure_channel(struct is32fl3207 *chip,
+					struct fwnode_handle *fwnode,
+					unsigned int *channel)
+{
+	u64 scaling;
+	u32 max_microamp;
+	u32 reg;
+	int ret;
+
+	ret = fwnode_property_read_u32(fwnode, "reg", &reg);
+	if (ret)
+		return dev_err_probe(chip->dev, ret,
+				     "failed to read channel for %pfw\n", fwnode);
+
+	if (reg >= IS32FL3207_NUM_CHANNELS)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "channel %u is out of range\n", reg);
+
+	if (test_bit(reg, chip->channels))
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "channel %u is used more than once\n", reg);
+
+	ret = fwnode_property_read_u32(fwnode, "led-max-microamp",
+				       &max_microamp);
+	if (ret)
+		return dev_err_probe(chip->dev, ret,
+				     "failed to read current limit for channel %u\n",
+				     reg);
+
+	if (!max_microamp || max_microamp > chip->output_max_microamp)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "invalid current limit %u uA for channel %u\n",
+				     max_microamp, reg);
+
+	/* GCC is fixed at 0xff, so use each output's scaling register. */
+	scaling = div_u64((u64)max_microamp * 256 * 256,
+			  (u64)chip->output_max_microamp *
+			  IS32FL3207_GLOBAL_CURRENT_MAX);
+	if (!scaling)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "current limit %u uA is below channel %u resolution\n",
+				     max_microamp, reg);
+
+	scaling = min_t(u64, scaling, 0xff);
+	ret = regmap_write(chip->regmap, IS32FL3207_REG_SCALING(reg),
+			   (unsigned int)scaling);
+	if (ret)
+		return ret;
+
+	set_bit(reg, chip->channels);
+	*channel = reg;
+
+	return 0;
+}
+
+static int is32fl3207_register_single(struct is32fl3207 *chip,
+				      struct fwnode_handle *fwnode,
+				      struct is32fl3207_led *led)
+{
+	struct led_init_data init_data = {
+		.devicename = dev_name(chip->dev),
+		.devname_mandatory = true,
+		.fwnode = fwnode,
+	};
+	unsigned int max_brightness;
+	u32 color;
+	int ret;
+
+	ret = is32fl3207_parse_led_properties(chip, fwnode,
+					      &max_brightness);
+	if (ret)
+		return ret;
+
+	if (fwnode_property_present(fwnode, "color")) {
+		ret = fwnode_property_read_u32(fwnode, "color", &color);
+		if (ret)
+			return dev_err_probe(chip->dev, ret,
+					     "failed to read color for %pfw\n",
+					     fwnode);
+		if (color >= LED_COLOR_ID_MAX || color == LED_COLOR_ID_MULTI ||
+		    color == LED_COLOR_ID_RGB)
+			return dev_err_probe(chip->dev, -EINVAL,
+					     "invalid single LED color %u\n", color);
+	}
+
+	ret = is32fl3207_configure_channel(chip, fwnode, &led->channel);
+	if (ret)
+		return ret;
+
+	led->chip = chip;
+	led->cdev.max_brightness = max_brightness;
+	led->cdev.brightness_set_blocking = is32fl3207_brightness_set;
+
+	return devm_led_classdev_register_ext(chip->dev, &led->cdev, &init_data);
+}
+
+static int is32fl3207_register_multicolor(struct is32fl3207 *chip,
+					  struct fwnode_handle *fwnode,
+					  struct is32fl3207_led *led)
+{
+	struct led_init_data init_data = {
+		.devicename = dev_name(chip->dev),
+		.devname_mandatory = true,
+		.fwnode = fwnode,
+	};
+	struct mc_subled *subleds;
+	DECLARE_BITMAP(color_map, LED_COLOR_ID_MAX);
+	unsigned int max_brightness;
+	unsigned int count;
+	unsigned int i = 0;
+	u32 group_color;
+	u32 group_reg;
+	unsigned int first_channel = IS32FL3207_NUM_CHANNELS;
+	int ret;
+
+	ret = is32fl3207_parse_led_properties(chip, fwnode,
+					      &max_brightness);
+	if (ret)
+		return ret;
+
+	ret = fwnode_property_read_u32(fwnode, "color", &group_color);
+	if (ret)
+		return dev_err_probe(chip->dev, ret,
+				     "failed to read color for %pfw\n", fwnode);
+
+	if (group_color != LED_COLOR_ID_RGB &&
+	    group_color != LED_COLOR_ID_MULTI)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "invalid multicolor LED color %u\n", group_color);
+
+	ret = fwnode_property_read_u32(fwnode, "reg", &group_reg);
+	if (ret)
+		return dev_err_probe(chip->dev, ret,
+				     "failed to read group index for %pfw\n", fwnode);
+
+	count = fwnode_get_child_node_count(fwnode);
+	if (!count || count > LED_COLOR_ID_MAX)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "invalid component count %u for %pfw\n",
+				     count, fwnode);
+
+	subleds = devm_kcalloc(chip->dev, count, sizeof(*subleds), GFP_KERNEL);
+	if (!subleds)
+		return -ENOMEM;
+	bitmap_zero(color_map, LED_COLOR_ID_MAX);
+
+	fwnode_for_each_child_node_scoped(fwnode, child) {
+		u32 color;
+
+		ret = is32fl3207_validate_component(chip, child);
+		if (ret)
+			return ret;
+
+		ret = fwnode_property_read_u32(child, "color", &color);
+		if (ret)
+			return dev_err_probe(chip->dev, ret,
+					     "failed to read color for %pfw\n",
+					     child);
+
+		if (color >= LED_COLOR_ID_MAX || color == LED_COLOR_ID_MULTI ||
+		    color == LED_COLOR_ID_RGB)
+			return dev_err_probe(chip->dev, -EINVAL,
+					     "invalid component color %u\n", color);
+		if (test_and_set_bit(color, color_map))
+			return dev_err_probe(chip->dev, -EINVAL,
+					     "component color %u is used more than once\n",
+					     color);
+
+		ret = is32fl3207_configure_channel(chip, child,
+						   &subleds[i].channel);
+		if (ret)
+			return ret;
+
+		subleds[i].color_index = color;
+		subleds[i].intensity = max_brightness;
+		subleds[i].max_intensity = 0;
+		first_channel = min(first_channel, subleds[i].channel);
+		i++;
+	}
+
+	if (group_reg != first_channel)
+		return dev_err_probe(chip->dev, -EINVAL,
+				     "group index %u does not match first channel %u\n",
+				     group_reg, first_channel);
+
+	led->chip = chip;
+	led->mcdev.num_colors = count;
+	led->mcdev.subled_info = subleds;
+	led->mcdev.led_cdev.max_brightness = max_brightness;
+	led->mcdev.led_cdev.brightness_set_blocking =
+		is32fl3207_mc_brightness_set;
+
+	return devm_led_classdev_multicolor_register_ext(chip->dev, &led->mcdev,
+						     &init_data);
+}
+
+static int is32fl3207_hw_init(struct is32fl3207 *chip)
+{
+	u8 scaling[IS32FL3207_NUM_CHANNELS];
+	u8 pwm[2 * IS32FL3207_NUM_CHANNELS] = { };
+	int ret;
+
+	ret = regmap_write(chip->regmap, IS32FL3207_REG_CONTROL,
+			   IS32FL3207_CONTROL_ENABLE);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(chip->regmap, IS32FL3207_REG_RESET, 0);
+	if (ret)
+		return ret;
+	usleep_range(200, 300);
+
+	ret = regmap_write(chip->regmap, IS32FL3207_REG_CONTROL,
+			   IS32FL3207_CONTROL_ENABLE);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(chip->regmap, IS32FL3207_REG_GLOBAL_CURRENT,
+			   IS32FL3207_GLOBAL_CURRENT_MAX);
+	if (ret)
+		return ret;
+
+	memset(scaling, 0xff, sizeof(scaling));
+	ret = regmap_bulk_write(chip->regmap, IS32FL3207_REG_SCALING(0),
+				scaling, sizeof(scaling));
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_write(chip->regmap, IS32FL3207_REG_PWM_LOW(0), pwm,
+				sizeof(pwm));
+	if (ret)
+		return ret;
+
+	return regmap_write(chip->regmap, IS32FL3207_REG_PWM_UPDATE, 0);
+}
+
+static void is32fl3207_disable(void *data)
+{
+	struct is32fl3207 *chip = data;
+
+	guard(mutex)(&chip->lock);
+	regmap_write(chip->regmap, IS32FL3207_REG_CONTROL, 0);
+	if (chip->enable_gpio)
+		gpiod_set_value_cansleep(chip->enable_gpio, 0);
+}
+
+static const struct regmap_config is32fl3207_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = IS32FL3207_REG_RESET,
+};
+
+static int is32fl3207_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct is32fl3207 *chip;
+	unsigned int count;
+	unsigned int i = 0;
+	u32 riset_ohms;
+	int ret;
+
+	count = device_get_child_node_count(dev);
+	if (!count || count > IS32FL3207_NUM_CHANNELS)
+		return dev_err_probe(dev, -EINVAL,
+				     "invalid LED count %u\n", count);
+
+	chip = devm_kzalloc(dev, struct_size(chip, leds, count), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = dev;
+	chip->num_leds = count;
+	i2c_set_clientdata(client, chip);
+
+	ret = device_property_read_u32(dev, "issi,riset-ohms", &riset_ohms);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to read RISET value\n");
+
+	if (riset_ohms < 2000)
+		return dev_err_probe(dev, -EINVAL,
+				     "RISET value %u is below 2000 ohms\n",
+				     riset_ohms);
+
+	chip->output_max_microamp = div_u64(IS32FL3207_CURRENT_NUMERATOR,
+					    riset_ohms);
+	if (!chip->output_max_microamp)
+		return dev_err_probe(dev, -EINVAL,
+				     "RISET value %u is too large\n", riset_ohms);
+
+	ret = devm_regulator_get_enable_optional(dev, "vcc");
+	if (ret && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable VCC regulator\n");
+
+	chip->enable_gpio = devm_gpiod_get_optional(dev, "enable",
+						    GPIOD_OUT_HIGH);
+	if (IS_ERR(chip->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(chip->enable_gpio),
+				     "failed to get enable GPIO\n");
+
+	if (chip->enable_gpio)
+		usleep_range(1000, 2000);
+
+	chip->regmap = devm_regmap_init_i2c(client, &is32fl3207_regmap_config);
+	if (IS_ERR(chip->regmap))
+		return dev_err_probe(dev, PTR_ERR(chip->regmap),
+				     "failed to allocate register map\n");
+
+	ret = devm_mutex_init(dev, &chip->lock);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, is32fl3207_disable, chip);
+	if (ret)
+		return ret;
+
+	ret = is32fl3207_hw_init(chip);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to initialize controller\n");
+
+	device_for_each_child_node_scoped(dev, child) {
+		struct is32fl3207_led *led = &chip->leds[i];
+
+		if (fwnode_get_child_node_count(child))
+			ret = is32fl3207_register_multicolor(chip, child, led);
+		else
+			ret = is32fl3207_register_single(chip, child, led);
+		if (ret)
+			return ret;
+
+		i++;
+	}
+
+	return 0;
+}
+
+static void is32fl3207_shutdown(struct i2c_client *client)
+{
+	is32fl3207_disable(i2c_get_clientdata(client));
+}
+
+static const struct of_device_id is32fl3207_of_match[] = {
+	{ .compatible = "issi,is32fl3207" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, is32fl3207_of_match);
+
+static const struct i2c_device_id is32fl3207_id[] = {
+	{ "is32fl3207" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is32fl3207_id);
+
+static struct i2c_driver is32fl3207_driver = {
+	.driver = {
+		.name = "is32fl3207",
+		.of_match_table = is32fl3207_of_match,
+	},
+	.probe = is32fl3207_probe,
+	.shutdown = is32fl3207_shutdown,
+	.id_table = is32fl3207_id,
+};
+module_i2c_driver(is32fl3207_driver);
+
+MODULE_AUTHOR("Ahmad Byagowi <ahmadexp@gmail.com>");
+MODULE_DESCRIPTION("Lumissil IS32FL3207 LED controller driver");
+MODULE_LICENSE("GPL");
-- 
2.50.1 (Apple Git-155)