leds: tlc591xx: Driver for the TI 8/16 Channel i2c LED driver

The TLC59116 is an I2C bus controlled 16-channel LED driver. The
TLC59108 is an I2C bus controlled 8-channel LED driver, which is very
similar to the TLC59116. Each LED output has its own 8-bit
fixed-frequency PWM controller to control the brightness of the LED.
The LEDs can also be fixed off and on, making them suitable for use as
GPOs.

This is based on a driver from Belkin, but has been extensively
rewritten and extended to support both 08 and 16 versions.

Signed-off-by: Andrew Lunn <[e-mail]>
Tested-by: Imre Kaloz <[e-mail]>
Cc: [e-mail]
Acked-by: Jacek Anaszewski <[e-mail]>
Signed-off-by: Bryan Wu <[e-mail]>

drivers/leds/Kconfig

···
 	  LED driver chips accessed via the I2C bus.
 	  Driver support brightness control and hardware-assisted blinking.
 
+config LEDS_TLC591XX
+	tristate "LED driver for TLC59108 and TLC59116 controllers"
+	depends on LEDS_CLASS && I2C
+	select REGMAP_I2C
+	help
+	  This option enables support for Texas Instruments TLC59108
+	  and TLC59116 LED controllers.
+
 config LEDS_MAX8997
 	tristate "LED support for MAX8997 PMIC"
 	depends on LEDS_CLASS && MFD_MAX8997

drivers/leds/Makefile

···
 obj-$(CONFIG_LEDS_LP8788)		+= leds-lp8788.o
 obj-$(CONFIG_LEDS_LP8860)		+= leds-lp8860.o
 obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
+obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
 obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o
 obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
 obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o

drivers/leds/leds-tlc591xx.c

···
+/*
+ * Copyright 2014 Belkin Inc.
+ * Copyright 2015 Andrew Lunn <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#define TLC591XX_MAX_LEDS	16
+
+#define TLC591XX_REG_MODE1	0x00
+#define MODE1_RESPON_ADDR_MASK	0xF0
+#define MODE1_NORMAL_MODE	(0 << 4)
+#define MODE1_SPEED_MODE	(1 << 4)
+
+#define TLC591XX_REG_MODE2	0x01
+#define MODE2_DIM		(0 << 5)
+#define MODE2_BLINK		(1 << 5)
+#define MODE2_OCH_STOP		(0 << 3)
+#define MODE2_OCH_ACK		(1 << 3)
+
+#define TLC591XX_REG_PWM(x)	(0x02 + (x))
+
+#define TLC591XX_REG_GRPPWM	0x12
+#define TLC591XX_REG_GRPFREQ	0x13
+
+/* LED Driver Output State, determine the source that drives LED outputs */
+#define LEDOUT_OFF		0x0	/* Output LOW */
+#define LEDOUT_ON		0x1	/* Output HI-Z */
+#define LEDOUT_DIM		0x2	/* Dimming */
+#define LEDOUT_BLINK		0x3	/* Blinking */
+#define LEDOUT_MASK		0x3
+
+#define ldev_to_led(c)		container_of(c, struct tlc591xx_led, ldev)
+#define work_to_led(work)	container_of(work, struct tlc591xx_led, work)
+
+struct tlc591xx_led {
+	bool active;
+	unsigned int led_no;
+	struct led_classdev ldev;
+	struct work_struct work;
+	struct tlc591xx_priv *priv;
+};
+
+struct tlc591xx_priv {
+	struct tlc591xx_led leds[TLC591XX_MAX_LEDS];
+	struct regmap *regmap;
+	unsigned int reg_ledout_offset;
+};
+
+struct tlc591xx {
+	unsigned int max_leds;
+	unsigned int reg_ledout_offset;
+};
+
+static const struct tlc591xx tlc59116 = {
+	.max_leds = 16,
+	.reg_ledout_offset = 0x14,
+};
+
+static const struct tlc591xx tlc59108 = {
+	.max_leds = 8,
+	.reg_ledout_offset = 0x0c,
+};
+
+static int
+tlc591xx_set_mode(struct regmap *regmap, u8 mode)
+{
+	int err;
+	u8 val;
+
+	err = regmap_write(regmap, TLC591XX_REG_MODE1, MODE1_NORMAL_MODE);
+	if (err)
+		return err;
+
+	val = MODE2_OCH_STOP | mode;
+
+	return regmap_write(regmap, TLC591XX_REG_MODE2, val);
+}
+
+static int
+tlc591xx_set_ledout(struct tlc591xx_priv *priv, struct tlc591xx_led *led,
+		    u8 val)
+{
+	unsigned int i = (led->led_no % 4) * 2;
+	unsigned int mask = LEDOUT_MASK << i;
+	unsigned int addr = priv->reg_ledout_offset + (led->led_no >> 2);
+
+	val = val << i;
+
+	return regmap_update_bits(priv->regmap, addr, mask, val);
+}
+
+static int
+tlc591xx_set_pwm(struct tlc591xx_priv *priv, struct tlc591xx_led *led,
+		 u8 brightness)
+{
+	u8 pwm = TLC591XX_REG_PWM(led->led_no);
+
+	return regmap_write(priv->regmap, pwm, brightness);
+}
+
+static void
+tlc591xx_led_work(struct work_struct *work)
+{
+	struct tlc591xx_led *led = work_to_led(work);
+	struct tlc591xx_priv *priv = led->priv;
+	enum led_brightness brightness = led->ldev.brightness;
+	int err;
+
+	switch (brightness) {
+	case 0:
+		err = tlc591xx_set_ledout(priv, led, LEDOUT_OFF);
+		break;
+	case LED_FULL:
+		err = tlc591xx_set_ledout(priv, led, LEDOUT_ON);
+		break;
+	default:
+		err = tlc591xx_set_ledout(priv, led, LEDOUT_DIM);
+		if (!err)
+			err = tlc591xx_set_pwm(priv, led, brightness);
+	}
+
+	if (err)
+		dev_err(led->ldev.dev, "Failed setting brightness\n");
+}
+
+static void
+tlc591xx_brightness_set(struct led_classdev *led_cdev,
+			enum led_brightness brightness)
+{
+	struct tlc591xx_led *led = ldev_to_led(led_cdev);
+
+	led->ldev.brightness = brightness;
+	schedule_work(&led->work);
+}
+
+static void
+tlc591xx_destroy_devices(struct tlc591xx_priv *priv, unsigned int j)
+{
+	int i = j;
+
+	while (--i >= 0) {
+		if (priv->leds[i].active) {
+			led_classdev_unregister(&priv->leds[i].ldev);
+			cancel_work_sync(&priv->leds[i].work);
+		}
+	}
+}
+
+static int
+tlc591xx_configure(struct device *dev,
+		   struct tlc591xx_priv *priv,
+		   const struct tlc591xx *tlc591xx)
+{
+	unsigned int i;
+	int err = 0;
+
+	tlc591xx_set_mode(priv->regmap, MODE2_DIM);
+	for (i = 0; i < TLC591XX_MAX_LEDS; i++) {
+		struct tlc591xx_led *led = &priv->leds[i];
+
+		if (!led->active)
+			continue;
+
+		led->priv = priv;
+		led->led_no = i;
+		led->ldev.brightness_set = tlc591xx_brightness_set;
+		led->ldev.max_brightness = LED_FULL;
+		INIT_WORK(&led->work, tlc591xx_led_work);
+		err = led_classdev_register(dev, &led->ldev);
+		if (err < 0) {
+			dev_err(dev, "couldn't register LED %s\n",
+				led->ldev.name);
+			goto exit;
+		}
+	}
+
+	return 0;
+
+exit:
+	tlc591xx_destroy_devices(priv, i);
+	return err;
+}
+
+static const struct regmap_config tlc591xx_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x1e,
+};
+
+static const struct of_device_id of_tlc591xx_leds_match[] = {
+	{ .compatible = "ti,tlc59116",
+	  .data = &tlc59116 },
+	{ .compatible = "ti,tlc59108",
+	  .data = &tlc59108 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_tlc591xx_leds_match);
+
+static int
+tlc591xx_probe(struct i2c_client *client,
+	       const struct i2c_device_id *id)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct device *dev = &client->dev;
+	const struct of_device_id *match;
+	const struct tlc591xx *tlc591xx;
+	struct tlc591xx_priv *priv;
+	int err, count, reg;
+
+	match = of_match_device(of_tlc591xx_leds_match, dev);
+	if (!match)
+		return -ENODEV;
+
+	tlc591xx = match->data;
+	if (!np)
+		return -ENODEV;
+
+	count = of_get_child_count(np);
+	if (!count || count > tlc591xx->max_leds)
+		return -EINVAL;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE_DATA))
+		return -EIO;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->regmap = devm_regmap_init_i2c(client, &tlc591xx_regmap);
+	if (IS_ERR(priv->regmap)) {
+		err = PTR_ERR(priv->regmap);
+		dev_err(dev, "Failed to allocate register map: %d\n", err);
+		return err;
+	}
+	priv->reg_ledout_offset = tlc591xx->reg_ledout_offset;
+
+	i2c_set_clientdata(client, priv);
+
+	for_each_child_of_node(np, child) {
+		err = of_property_read_u32(child, "reg", &reg);
+		if (err)
+			return err;
+		if (reg < 0 || reg >= tlc591xx->max_leds)
+			return -EINVAL;
+		if (priv->leds[reg].active)
+			return -EINVAL;
+		priv->leds[reg].active = true;
+		priv->leds[reg].ldev.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		priv->leds[reg].ldev.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+	}
+	return tlc591xx_configure(dev, priv, tlc591xx);
+}
+
+static int
+tlc591xx_remove(struct i2c_client *client)
+{
+	struct tlc591xx_priv *priv = i2c_get_clientdata(client);
+
+	tlc591xx_destroy_devices(priv, TLC591XX_MAX_LEDS);
+
+	return 0;
+}
+
+static const struct i2c_device_id tlc591xx_id[] = {
+	{ "tlc59116" },
+	{ "tlc59108" },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, tlc591xx_id);
+
+static struct i2c_driver tlc591xx_driver = {
+	.driver = {
+		.name = "tlc591xx",
+		.of_match_table = of_match_ptr(of_tlc591xx_leds_match),
+	},
+	.probe = tlc591xx_probe,
+	.remove = tlc591xx_remove,
+	.id_table = tlc591xx_id,
+};
+
+module_i2c_driver(tlc591xx_driver);
+
+MODULE_AUTHOR("Andrew Lunn <[e-mail]>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TLC591XX LED driver");