[PATCH RFC 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       |    8 ++
 drivers/leds/Makefile      |    1 +
 drivers/leds/leds-sn3218.c |  254 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 263 insertions(+)
 create mode 100644 drivers/leds/leds-sn3218.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7f940c2..4a1bb4e 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -568,6 +568,14 @@ 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
+	help
+	  This option enables support for the Si-EN SN3218 LED driver
+	  through I2C. Say Y to enable support for the SN3218 LED.
+
 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..f52e7cc
--- /dev/null
+++ b/drivers/leds/leds-sn3218.c
@@ -0,0 +1,254 @@
+/*
+ * 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/mutex.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#define SN3218_MODE		0x00
+#define SN3218_PWM_BASE		0x01
+#define SN3218_LED_BASE		0x13	/* 6 channels per reg */
+#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
+
+static const struct i2c_device_id sn3218_id[] = {
+	{ "sn3218", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, sn3218_id);
+
+struct sn3218_led;
+
+/**
+ * struct sn3218 -
+ * @lock - Lock for writing the device
+ * @client - Pointer to the I2C client
+ * @leds - Pointer to the individual LEDs
+ * @leds_state - Copy of LED CTRL registers
+**/
+struct sn3218 {
+	struct mutex lock;
+	struct i2c_client *client;
+	struct sn3218_led *leds;
+	u8 leds_state[3];
+};
+
+/**
+ * struct sn3218_led -
+ * @chip - Pointer to the container
+ * @led_cdev - led class device pointer
+ * @led_num - LED index ( 0 .. 17 )
+ * @name - LED name
+**/
+struct sn3218_led {
+	struct sn3218 *chip;
+	struct led_classdev led_cdev;
+	int led_num;
+	char name[32];
+};
+
+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 i2c_client *client = led->chip->client;
+	u8 bank = led->led_num / 6;
+	u8 mask = 0x1 << (led->led_num % 6);
+	int ret;
+
+	mutex_lock(&led->chip->lock);
+
+	if (brightness == LED_OFF)
+		led->chip->leds_state[bank] &= ~mask;
+	else
+		led->chip->leds_state[bank] |= mask;
+
+	ret = i2c_smbus_write_byte_data(client, SN3218_LED_BASE + bank,
+					led->chip->leds_state[bank]);
+	if (ret < 0)
+		goto unlock;
+
+	if (brightness > LED_OFF) {
+		ret = i2c_smbus_write_byte_data(client,
+				SN3218_PWM_BASE + led->led_num,	brightness);
+		if (ret < 0)
+			goto unlock;
+	}
+
+	ret = i2c_smbus_write_byte_data(client, SN3218_UPDATE, 0xFF);
+
+unlock:
+	mutex_unlock(&led->chip->lock);
+	return ret;
+}
+
+static struct led_platform_data *sn3218_init(struct i2c_client *client)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct led_platform_data *pdata;
+	struct led_info *sn3218_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	if (!count || count > NUM_LEDS)
+		return NULL;
+
+	sn3218_leds = devm_kzalloc(&client->dev,
+				sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!sn3218_leds)
+		return NULL;
+
+	for_each_child_of_node(np, child) {
+		struct led_info led = {};
+		u32 reg;
+		int ret;
+
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret != 0 || reg < 0 || reg >= NUM_LEDS)
+			continue;
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+		sn3218_leds[reg] = led;
+	}
+
+	pdata = devm_kzalloc(&client->dev, sizeof(struct led_platform_data),
+			     GFP_KERNEL);
+
+	pdata->leds = sn3218_leds;
+	pdata->num_leds = NUM_LEDS;
+
+	return pdata;
+}
+
+static const struct of_device_id of_sn3218_match[] = {
+	{ .compatible = "si-en,sn3218", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_sn3218_match);
+
+static int sn3218_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct led_platform_data *pdata;
+	struct sn3218 *sn3218_chip;
+	struct sn3218_led *sn3218;
+	int i, ret;
+
+	pdata = sn3218_init(client);
+	if (IS_ERR(pdata))
+		return PTR_ERR(pdata);
+
+	sn3218_chip = devm_kzalloc(&client->dev, sizeof(*sn3218_chip),
+				   GFP_KERNEL);
+	if (!sn3218_chip)
+		return -ENOMEM;
+
+	sn3218 = devm_kzalloc(&client->dev, NUM_LEDS * sizeof(*sn3218),
+			      GFP_KERNEL);
+	if (!sn3218)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, sn3218_chip);
+
+	mutex_init(&sn3218_chip->lock);
+	sn3218_chip->client = client;
+	sn3218_chip->leds = sn3218;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		sn3218[i].led_num = i;
+		sn3218[i].chip = sn3218_chip;
+
+		if (i < pdata->num_leds) {
+			if (pdata->leds[i].name)
+				snprintf(sn3218[i].name,
+					 sizeof(sn3218[i].name), "sn3218:%s",
+					 pdata->leds[i].name);
+			if (pdata->leds[i].default_trigger)
+				sn3218[i].led_cdev.default_trigger =
+					pdata->leds[i].default_trigger;
+		}
+
+		if (i >= pdata->num_leds || !pdata->leds[i].name) {
+			snprintf(sn3218[i].name, sizeof(sn3218[i].name),
+				 "sn3218:%d:%.2x:%d", client->adapter->nr,
+				 client->addr, i);
+		}
+
+		sn3218[i].led_cdev.name = sn3218[i].name;
+		sn3218[i].led_cdev.brightness_set_blocking = sn3218_led_set;
+		sn3218[i].led_cdev.max_brightness = LED_FULL;
+
+		ret = led_classdev_register(&client->dev, &sn3218[i].led_cdev);
+		if (ret < 0)
+			goto exit;
+	}
+
+	/* Reset chip to default, all LEDs off */
+	i2c_smbus_write_byte_data(client, SN3218_RESET, 0xFF);
+
+	/* Set normal mode */
+	i2c_smbus_write_byte_data(client, SN3218_MODE, 0x01);
+
+	return 0;
+
+exit:
+	while (i--)
+		led_classdev_unregister(&sn3218[i].led_cdev);
+
+	return ret;
+}
+
+static int sn3218_remove(struct i2c_client *client)
+{
+	struct sn3218 *sn3218 = i2c_get_clientdata(client);
+	int i;
+
+	for (i = 0; i < NUM_LEDS; i++)
+		led_classdev_unregister(&sn3218->leds[i].led_cdev);
+
+	/* Set shutdown mode */
+	i2c_smbus_write_byte_data(client, SN3218_MODE, 0x00);
+
+	return 0;
+}
+
+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");
-- 
1.7.9.5