leds: aw21024: Add support for Awinic's AW21024

The Awinic AW21024 LED controller is a 24-channel RGB LED controller.
Each LED on the controller can be controlled individually or grouped
with other LEDs on the controller to form a multi-color LED.  Arbitrary
combinations of individual and grouped LED control should be possible.

Signed-off-by: Kyle Swenson <kyle.swenson@est.tech>

drivers/leds/Kconfig

@@ -104,6 +104,17 @@ config LEDS_AW2013
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-aw2013.
 
+config LEDS_AW21024
+	tristate "LED Support for Awinic AW21024"
+	depends on LEDS_CLASS
+	depends on LEDS_CLASS_MULTICOLOR || !LEDS_CLASS_MULTICOLOR
+	help
+	  If you say yes here you get support for Awinic's AW21024, a 24-channel
+	  RGB LED Driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called leds-aw21024.
+
 config LEDS_BCM6328
 	tristate "LED Support for Broadcom BCM6328"
 	depends on LEDS_CLASS

drivers/leds/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_ARIEL)		+= leds-ariel.o
 obj-$(CONFIG_LEDS_ASIC3)		+= leds-asic3.o
 obj-$(CONFIG_LEDS_AW2013)		+= leds-aw2013.o
+obj-$(CONFIG_LEDS_AW21024)		+= leds-aw21024.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
 obj-$(CONFIG_LEDS_BCM6358)		+= leds-bcm6358.o
 obj-$(CONFIG_LEDS_BD2802)		+= leds-bd2802.o

drivers/leds/leds-aw21024.c

@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0
+// Awinic AW21024 LED chip driver
+// Copyright (C) 2022 Nordix Foundation https://www.nordix.org
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+#include <linux/led-class-multicolor.h>
+
+/* Called COL0, COL1,..., COL23 in datasheet */
+#define AW21024_REG_DC_CURRENT(_led)	(0x4a + (_led))
+
+/* Called BR0, BR1,..., BR23 in datasheet */
+#define AW21024_REG_BRIGHTNESS(_led)	(0x01 + (_led))
+
+#define AW21024_REG_UPDATE				0x49 /* Write 0x00 to update BR */
+
+#define AW21024_REG_GCR0				0x00 /* Global configuration register */
+#define AW21024_REG_GCC					0x6e /* Global current control */
+#define AW21024_REG_SW_RESET			0x7f
+#define AW21024_REG_VERSION				0x7e
+
+#define AW21024_GCR0_CHIPEN				BIT(0)
+#define AW21024_CHIP_ID					0x18
+#define AW21024_CHIP_VERSION			0xA8
+
+struct aw21024_led_data {
+	struct led_classdev_mc mc_cdev;
+	struct work_struct work;
+	unsigned int *regs;
+	unsigned int nregs;
+	struct aw21024 *parent;
+};
+
+struct aw21024 {
+	struct i2c_client *client;
+	struct device *dev;
+	struct gpio_desc *enable_gpio;
+	struct mutex lock;
+	struct aw21024_led_data **leds;
+	unsigned int nleds;
+};
+
+static int aw21024_led_brightness_set(struct led_classdev *led_cdev,
+					enum led_brightness brightness)
+{
+	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(led_cdev);
+	struct aw21024_led_data *led = container_of(mc_cdev, struct aw21024_led_data, mc_cdev);
+	struct aw21024 *parent = led->parent;
+	int i;
+	int ret = 0;
+
+	mutex_lock(&parent->lock);
+	if (mc_cdev->num_colors && mc_cdev->subled_info) {
+		for (i = 0; i < led->nregs; i++) {
+			ret = i2c_smbus_write_byte_data(parent->client,
+					AW21024_REG_DC_CURRENT(led->regs[i]),
+					mc_cdev->subled_info[i].intensity);
+			if (ret < 0)
+				goto unlock_ret;
+
+			ret = i2c_smbus_write_byte_data(parent->client,
+					AW21024_REG_BRIGHTNESS(led->regs[i]),
+					brightness);
+			if (ret < 0)
+				goto unlock_ret;
+		}
+	} else {
+		ret = i2c_smbus_write_byte_data(parent->client,
+					AW21024_REG_DC_CURRENT(led->regs[0]), 0xFF);
+		if (ret < 0)
+			goto unlock_ret;
+
+		ret = i2c_smbus_write_byte_data(parent->client,
+					AW21024_REG_BRIGHTNESS(led->regs[0]),
+					brightness);
+		if (ret < 0)
+			goto unlock_ret;
+	}
+	ret = i2c_smbus_write_byte_data(parent->client, AW21024_REG_UPDATE, 0x0);
+unlock_ret:
+	mutex_unlock(&parent->lock);
+	return ret;
+}
+
+static int aw21024_probe_dt(struct aw21024 *data)
+{
+	struct device *dev = &data->client->dev;
+	struct fwnode_handle *child = NULL;
+	struct fwnode_handle *led_node = NULL;
+	struct led_init_data init_data = {};
+	u32 color_id;
+	int  ret, num_colors;
+	unsigned int nleds = 0;
+	struct aw21024_led_data *led;
+	struct led_classdev *led_cdev;
+	struct mc_subled *mc_led_info;
+
+	nleds = device_get_child_node_count(dev);
+
+	data->leds = devm_kcalloc(dev, nleds, sizeof(*(data->leds)), GFP_KERNEL);
+	if (!data->leds)
+		return -ENOMEM;
+
+	device_for_each_child_node(dev, child) {
+		led = devm_kzalloc(dev, sizeof(struct aw21024_led_data), GFP_KERNEL);
+		if (!led) {
+			ret = -ENOMEM;
+			goto ret_put_child;
+		}
+		led->parent = data;
+		led_cdev = &led->mc_cdev.led_cdev;
+		init_data.fwnode = child;
+
+		led_cdev->brightness_set_blocking = aw21024_led_brightness_set;
+		data->leds[data->nleds] = led;
+
+		ret = fwnode_property_count_u32(child, "reg");
+		if (ret < 0) {
+			dev_err(dev, "reg property is invalid in node %s\n",
+					fwnode_get_name(child));
+			goto ret_put_child;
+		}
+
+		led->regs = devm_kcalloc(dev, ret, sizeof(*(led->regs)), GFP_KERNEL);
+		led->nregs = ret;
+		if (!led->regs) {
+			ret = -ENOMEM;
+			goto ret_put_child;
+		}
+
+		ret = fwnode_property_read_u32_array(child, "reg", led->regs, led->nregs);
+		if (ret) {
+			dev_err(dev, "Failed to read reg array, error=%d\n", ret);
+			goto ret_put_child;
+		}
+
+		if (led->nregs > 1) {
+			mc_led_info = devm_kcalloc(dev, led->nregs,
+						    sizeof(*mc_led_info), GFP_KERNEL);
+			if (!mc_led_info) {
+				ret = -ENOMEM;
+				goto ret_put_child;
+			}
+
+			num_colors = 0;
+			fwnode_for_each_child_node(child, led_node) {
+				if (num_colors > led->nregs) {
+					ret = -EINVAL;
+					fwnode_handle_put(led_node);
+					goto ret_put_child;
+				}
+
+				ret = fwnode_property_read_u32(led_node, "color",
+							       &color_id);
+				if (ret) {
+					fwnode_handle_put(led_node);
+					goto ret_put_child;
+				}
+				mc_led_info[num_colors].color_index = color_id;
+				num_colors++;
+			}
+
+			led->mc_cdev.num_colors = num_colors;
+			led->mc_cdev.subled_info = mc_led_info;
+			ret = devm_led_classdev_multicolor_register_ext(dev,
+								&led->mc_cdev,
+								&init_data);
+			if (ret < 0) {
+				dev_warn(dev, "Failed to register multicolor LED %s, err=%d\n",
+						    fwnode_get_name(child), ret);
+				goto ret_put_child;
+			}
+		} else {
+			ret = devm_led_classdev_register_ext(dev,
+							    &led->mc_cdev.led_cdev, &init_data);
+			if (ret < 0) {
+				dev_warn(dev, "Failed to register LED %s, err=%d\n",
+						fwnode_get_name(child), ret);
+				goto ret_put_child;
+			}
+		}
+		data->nleds++;
+	}
+
+	return 0;
+
+ret_put_child:
+	fwnode_handle_put(child);
+	return ret;
+}
+
+/* Expected to be called prior to registering with the LEDs class */
+static int aw21024_configure(struct aw21024 *priv)
+{
+	int ret = 0;
+	struct i2c_client *client = priv->client;
+
+	ret = i2c_smbus_write_byte_data(client, AW21024_REG_GCR0, AW21024_GCR0_CHIPEN);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to write chip enable\n");
+		return -ENODEV;
+	}
+
+	ret = i2c_smbus_read_byte_data(client, AW21024_REG_SW_RESET);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read chip id\n");
+		return -ENODEV;
+	}
+
+	if (ret != AW21024_CHIP_ID) {
+		dev_err(&client->dev, "Chip ID 0x%02X doesn't match expected (0x%02X)\n",
+								ret, AW21024_CHIP_ID);
+		return -ENODEV;
+	}
+
+	ret = i2c_smbus_read_byte_data(client, AW21024_REG_VERSION);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read chip version\n");
+		return -ENODEV;
+	}
+	if (ret != AW21024_CHIP_VERSION)
+		dev_warn(&client->dev, "Chip version 0x%02X doesn't match expected 0x%02X\n",
+								ret, AW21024_CHIP_VERSION);
+
+	i2c_smbus_write_byte_data(client, AW21024_REG_SW_RESET, 0x00);
+	mdelay(2);
+	i2c_smbus_write_byte_data(client, AW21024_REG_GCR0, AW21024_GCR0_CHIPEN);
+	i2c_smbus_write_byte_data(client, AW21024_REG_GCC, 0xFF);
+
+	return 0;
+}
+
+static int aw21024_probe(struct i2c_client *client)
+{
+	struct aw21024 *priv;
+	int ret;
+
+	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+	priv->dev = &client->dev;
+
+	mutex_init(&priv->lock);
+
+	priv->enable_gpio = devm_gpiod_get_optional(priv->dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->enable_gpio))
+		return dev_err_probe(priv->dev, PTR_ERR(priv->enable_gpio),
+				       "Failed to get enable GPIO\n");
+
+	if (priv->enable_gpio) {
+		mdelay(1);
+		gpiod_direction_output(priv->enable_gpio, 1);
+		mdelay(1);
+	}
+
+	i2c_set_clientdata(client, priv);
+
+	ret = aw21024_configure(priv);
+	if (ret < 0)
+		return ret;
+
+	return aw21024_probe_dt(priv);
+}
+
+static int aw21024_remove(struct i2c_client *client)
+{
+	struct aw21024 *priv = i2c_get_clientdata(client);
+	int ret;
+
+	ret = gpiod_direction_output(priv->enable_gpio, 0);
+	if (ret)
+		dev_err(priv->dev, "Failed to disable chip, err=%d\n", ret);
+
+	mutex_destroy(&priv->lock);
+	return 0;
+}
+
+static const struct i2c_device_id aw21024_id[] = {
+	{ "aw21024", 0 }, /* 24 Channel */
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, aw21024_id);
+
+static const struct of_device_id of_aw21024_leds_match[] = {
+	{ .compatible = "awinic,aw21024", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_aw21024_leds_match);
+
+static struct i2c_driver aw21024_driver = {
+	.driver		= {
+		.name	= "aw21024",
+		.of_match_table = of_match_ptr(of_aw21024_leds_match),
+	},
+	.probe_new		= aw21024_probe,
+	.remove		= aw21024_remove,
+	.id_table = aw21024_id,
+};
+module_i2c_driver(aw21024_driver);
+
+MODULE_AUTHOR("Kyle Swenson <kyle.swenson@est.tech>");
+MODULE_DESCRIPTION("Awinic AW21024 LED driver");
+MODULE_LICENSE("GPL");