[PATCH 3/3] leds: add SN3218 LED driver

[Stefan Wahren]

This patch adds support for Si-En SN3218 18 Channel LED Driver.

Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
---
 drivers/leds/Kconfig       |   12 ++
 drivers/leds/Makefile      |    1 +
 drivers/leds/leds-sn3218.c |  297 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 310 insertions(+)
 create mode 100644 drivers/leds/leds-sn3218.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7f940c2..920c2da 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -568,6 +568,18 @@ config LEDS_SEAD3
 	  This driver can also be built as a module. If so the module
 	  will be called leds-sead3.
 
+config LEDS_SN3218
+	tristate "LED support for Si-En SN3218 I2C chip"
+	depends on LEDS_CLASS && I2C
+	depends on OF
+	select REGMAP_I2C
+	help
+	  This option enables support for the Si-EN SN3218 LED driver
+	  connected through I2C. Say Y to enable support for the SN3218 LED.
+
+	  This driver can also be built as a module. If so the module
+	  will be called leds-sn3218.
+
 comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
 
 config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index e9d5309..89c9b6f 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_LEDS_MENF21BMC)		+= leds-menf21bmc.o
 obj-$(CONFIG_LEDS_KTD2692)		+= leds-ktd2692.o
 obj-$(CONFIG_LEDS_POWERNV)		+= leds-powernv.o
 obj-$(CONFIG_LEDS_SEAD3)		+= leds-sead3.o
+obj-$(CONFIG_LEDS_SN3218)		+= leds-sn3218.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-sn3218.c b/drivers/leds/leds-sn3218.c
new file mode 100644
index 0000000..7a96323
--- /dev/null
+++ b/drivers/leds/leds-sn3218.c
@@ -0,0 +1,297 @@
+/*
+ * Si-En SN3218 18 Channel LED Driver
+ *
+ * Copyright (C) 2016 Stefan Wahren <stefan.wahren@xxxxxxxx>
+ *
+ * Based on leds-pca963x.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * Datasheet: http://www.si-en.com/uploadpdf/s2011517171720.pdf
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define SN3218_MODE		0x00
+#define SN3218_PWM_1		0x01
+#define SN3218_PWM_2		0x02
+#define SN3218_PWM_3		0x03
+#define SN3218_PWM_4		0x04
+#define SN3218_PWM_5		0x05
+#define SN3218_PWM_6		0x06
+#define SN3218_PWM_7		0x07
+#define SN3218_PWM_8		0x08
+#define SN3218_PWM_9		0x09
+#define SN3218_PWM_10		0x0a
+#define SN3218_PWM_11		0x0b
+#define SN3218_PWM_12		0x0c
+#define SN3218_PWM_13		0x0d
+#define SN3218_PWM_14		0x0e
+#define SN3218_PWM_15		0x0f
+#define SN3218_PWM_16		0x10
+#define SN3218_PWM_17		0x11
+#define SN3218_PWM_18		0x12
+#define SN3218_LED_1_6		0x13
+#define SN3218_LED_7_12		0x14
+#define SN3218_LED_13_18	0x15
+#define SN3218_UPDATE		0x16	/* applies to reg 0x01 .. 0x15 */
+#define SN3218_RESET		0x17
+
+#define SN3218_LED_MASK		0x3f
+#define SN3218_LED_ON		0x01
+#define SN3218_LED_OFF		0x00
+
+#define NUM_LEDS		18
+
+struct sn3218_led;
+
+/**
+ * struct sn3218 -
+ * @client - Pointer to the I2C client
+ * @leds - Pointer to the individual LEDs
+ * @num_leds - Actual number of LEDs
+**/
+struct sn3218 {
+	struct i2c_client *client;
+	struct regmap *regmap;
+	struct sn3218_led *leds;
+	int num_leds;
+};
+
+/**
+ * struct sn3218_led -
+ * @chip - Pointer to the container
+ * @led_cdev - led class device pointer
+ * @led_num - LED index ( 0 .. 17 )
+**/
+struct sn3218_led {
+	struct sn3218 *chip;
+	struct led_classdev led_cdev;
+	int led_num;
+};
+
+static int sn3218_led_set(struct led_classdev *led_cdev,
+			  enum led_brightness brightness)
+{
+	struct sn3218_led *led =
+			container_of(led_cdev, struct sn3218_led, led_cdev);
+	struct regmap *regmap = led->chip->regmap;
+	u8 bank = led->led_num / 6;
+	u8 mask = 0x1 << (led->led_num % 6);
+	u8 val;
+	int ret;
+
+	if (brightness == LED_OFF)
+		val = 0;
+	else
+		val = mask;
+
+	ret = regmap_update_bits(regmap, SN3218_LED_1_6 + bank, mask, val);
+	if (ret < 0)
+		return ret;
+
+	if (brightness > LED_OFF) {
+		ret = regmap_write(regmap, SN3218_PWM_1 + led->led_num,
+				   brightness);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = regmap_write(regmap, SN3218_UPDATE, 0xff);
+
+	return ret;
+}
+
+void sn3218_led_init(struct sn3218 *sn3218, struct device_node *node, u32 reg)
+{
+	struct sn3218_led *leds = sn3218->leds;
+	struct led_classdev *cdev = &leds[reg].led_cdev;
+
+	leds[reg].led_num = reg;
+	leds[reg].chip = sn3218;
+
+	if (of_property_read_string(node, "label", &cdev->name))
+		cdev->name = node->name;
+
+	of_property_read_string(node, "linux,default-trigger",
+				&cdev->default_trigger);
+
+	cdev->brightness_set_blocking = sn3218_led_set;
+	cdev->max_brightness = LED_FULL;
+}
+
+static const struct reg_default sn3218_reg_defs[] = {
+	{ SN3218_MODE, 0x00},
+	{ SN3218_PWM_1, 0x00},
+	{ SN3218_PWM_2, 0x00},
+	{ SN3218_PWM_3, 0x00},
+	{ SN3218_PWM_4, 0x00},
+	{ SN3218_PWM_5, 0x00},
+	{ SN3218_PWM_6, 0x00},
+	{ SN3218_PWM_7, 0x00},
+	{ SN3218_PWM_8, 0x00},
+	{ SN3218_PWM_9, 0x00},
+	{ SN3218_PWM_10, 0x00},
+	{ SN3218_PWM_11, 0x00},
+	{ SN3218_PWM_12, 0x00},
+	{ SN3218_PWM_13, 0x00},
+	{ SN3218_PWM_14, 0x00},
+	{ SN3218_PWM_15, 0x00},
+	{ SN3218_PWM_16, 0x00},
+	{ SN3218_PWM_17, 0x00},
+	{ SN3218_PWM_18, 0x00},
+	{ SN3218_LED_1_6, 0x00},
+	{ SN3218_LED_7_12, 0x00},
+	{ SN3218_LED_13_18, 0x00},
+	{ SN3218_UPDATE, 0x00},
+	{ SN3218_RESET, 0x00},
+};
+
+static const struct regmap_config sn3218_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = SN3218_RESET,
+	.reg_defaults = sn3218_reg_defs,
+	.num_reg_defaults = ARRAY_SIZE(sn3218_reg_defs),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int sn3218_init(struct i2c_client *client, struct sn3218 *sn3218)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct sn3218_led *leds;
+	int ret, count;
+
+	count = of_get_child_count(np);
+	if (!count)
+		return -ENODEV;
+
+	if (count > NUM_LEDS) {
+		dev_err(&client->dev, "Invalid LED count %d\n", count);
+		return -EINVAL;
+	}
+
+	leds = devm_kzalloc(&client->dev, count * sizeof(*leds), GFP_KERNEL);
+	if (!leds)
+		return -ENOMEM;
+
+	sn3218->leds = leds;
+	sn3218->num_leds = count;
+	sn3218->client = client;
+
+	sn3218->regmap = devm_regmap_init_i2c(client, &sn3218_regmap_config);
+	if (IS_ERR(sn3218->regmap)) {
+		ret = PTR_ERR(sn3218->regmap);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	for_each_child_of_node(np, child) {
+		u32 reg;
+
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret)
+			goto fail;
+
+		if (reg >= count) {
+			dev_err(&client->dev, "Invalid LED (%u >= %d)\n", reg,
+				count);
+			ret = -EINVAL;
+			goto fail;
+		}
+
+		sn3218_led_init(sn3218, child, reg);
+	}
+
+	return 0;
+
+fail:
+	of_node_put(np);
+	return ret;
+}
+
+static int sn3218_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct sn3218 *sn3218;
+	struct sn3218_led *leds;
+	struct device *dev = &client->dev;
+	int i, ret;
+
+	sn3218 = devm_kzalloc(dev, sizeof(*sn3218), GFP_KERNEL);
+	if (!sn3218)
+		return -ENOMEM;
+
+	ret = sn3218_init(client, sn3218);
+	if (ret)
+		return ret;
+
+	i2c_set_clientdata(client, sn3218);
+	leds = sn3218->leds;
+
+	/*
+	 * Since the chip is write-only we need to reset him into
+	 * a defined state (all LEDs off).
+	 */
+	ret = regmap_write(sn3218->regmap, SN3218_RESET, 0xff);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < sn3218->num_leds; i++) {
+		ret = devm_led_classdev_register(dev, &leds[i].led_cdev);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Set normal mode */
+	return regmap_write(sn3218->regmap, SN3218_MODE, 0x01);
+}
+
+static int sn3218_remove(struct i2c_client *client)
+{
+	struct sn3218 *sn3218 = i2c_get_clientdata(client);
+
+	/* Set shutdown mode */
+	regmap_write(sn3218->regmap, SN3218_MODE, 0x00);
+
+	return 0;
+}
+
+static const struct i2c_device_id sn3218_id[] = {
+	{ "sn3218", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, sn3218_id);
+
+static const struct of_device_id of_sn3218_match[] = {
+	{ .compatible = "si-en,sn3218", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_sn3218_match);
+
+static struct i2c_driver sn3218_driver = {
+	.driver = {
+		.name	= "leds-sn3218",
+		.of_match_table = of_match_ptr(of_sn3218_match),
+	},
+	.probe	= sn3218_probe,
+	.remove	= sn3218_remove,
+	.id_table = sn3218_id,
+};
+
+module_i2c_driver(sn3218_driver);
+
+MODULE_DESCRIPTION("Si-En SN3218 LED Driver");
+MODULE_AUTHOR("Stefan Wahren <stefan.wahren@xxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5