[PATCH v6 2/2] leds: lm3697: Introduce the lm3697 driver

[Dan Murphy]

Introduce the lm3697 LED driver for
backlighting and display.

Datasheet location:
http://www.ti.com/lit/ds/symlink/lm3697.pdf

Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
---

v6 - Fix nitpicks - https://lore.kernel.org/patchwork/patch/975388/

v5 - Fix nitpick issues with code - https://lore.kernel.org/patchwork/patch/975061/
v4 - Made modifications to the control bank routine to accomodate the DT changes
https://lore.kernel.org/patchwork/patch/974811/
v3 - Add code to support led-sources and control bank configuration also fix
other miscellaneous issues reported- https://lore.kernel.org/patchwork/patch/972336/
v2 - Removed unneed 'of' calls in dt_parse, fixed comment, fixed checkpatch
error, and change led registration - https://lore.kernel.org/patchwork/patch/971327/


 drivers/leds/Kconfig       |   9 +
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-lm3697.c | 379 +++++++++++++++++++++++++++++++++++++
 3 files changed, 389 insertions(+)
 create mode 100644 drivers/leds/leds-lm3697.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 44097a3e0fcc..784cbe375724 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -151,6 +151,15 @@ config LEDS_LM3642
 	  converter plus 1.5A constant current driver for a high-current
 	  white LED.
 
+config LEDS_LM3697
+	tristate "LED support for LM3697 Chip"
+	depends on LEDS_CLASS && I2C
+	select REGMAP_I2C
+	help
+	  This option enables support for LEDs connected to LM3697.
+	  The LM3697 is an 11 bit high performance backlight driver for
+	  keypad and display lighting.
+
 config LEDS_LM3692X
 	tristate "LED support for LM3692x Chips"
 	depends on LEDS_CLASS && I2C && OF
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 420b5d2cfa62..2813f089f3db 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_LEDS_LOCOMO)		+= leds-locomo.o
 obj-$(CONFIG_LEDS_LM3530)		+= leds-lm3530.o
 obj-$(CONFIG_LEDS_LM3533)		+= leds-lm3533.o
 obj-$(CONFIG_LEDS_LM3642)		+= leds-lm3642.o
+obj-$(CONFIG_LEDS_LM3697)		+= leds-lm3697.o
 obj-$(CONFIG_LEDS_MIKROTIK_RB532)	+= leds-rb532.o
 obj-$(CONFIG_LEDS_S3C24XX)		+= leds-s3c24xx.o
 obj-$(CONFIG_LEDS_NET48XX)		+= leds-net48xx.o
diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
new file mode 100644
index 000000000000..ef42336ef68e
--- /dev/null
+++ b/drivers/leds/leds-lm3697.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0
+// TI LM3697 LED chip family driver
+// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+#define LM3697_REV			0x0
+#define LM3697_RESET			0x1
+#define LM3697_OUTPUT_CONFIG		0x10
+#define LM3697_CTRL_A_RAMP		0x11
+#define LM3697_CTRL_B_RAMP		0x12
+#define LM3697_CTRL_A_B_RT_RAMP		0x13
+#define LM3697_CTRL_A_B_RAMP_CFG	0x14
+#define LM3697_CTRL_A_B_BRT_CFG		0x16
+#define LM3697_CTRL_A_FS_CURR_CFG	0x17
+#define LM3697_CTRL_B_FS_CURR_CFG	0x18
+#define LM3697_PWM_CFG			0x1c
+#define LM3697_CTRL_A_BRT_LSB		0x20
+#define LM3697_CTRL_A_BRT_MSB		0x21
+#define LM3697_CTRL_B_BRT_LSB		0x22
+#define LM3697_CTRL_B_BRT_MSB		0x23
+#define LM3697_CTRL_ENABLE		0x24
+
+#define LM3697_SW_RESET		BIT(0)
+
+#define LM3697_CTRL_A_EN	BIT(0)
+#define LM3697_CTRL_B_EN	BIT(1)
+#define LM3697_CTRL_A_B_EN	(LM3697_CTRL_A_EN | LM3697_CTRL_B_EN)
+
+#define LM3697_MAX_LED_STRINGS	3
+
+#define LM3697_CONTROL_A	0
+#define LM3697_CONTROL_B	1
+#define LM3697_HVLED_ASSIGNMENT	1
+
+/**
+ * struct lm3697_led -
+ * @hvled_strings - Array of LED strings associated with a control bank
+ * @label - LED label
+ * @led_dev - LED class device
+ * @priv - Pointer to the device struct
+ * @control_bank - Control bank the LED is associated to. 0 is control bank A
+ *		   1 is control bank B.
+ */
+struct lm3697_led {
+	u32 hvled_strings[LM3697_MAX_LED_STRINGS];
+	char label[LED_MAX_NAME_SIZE];
+	struct led_classdev led_dev;
+	struct lm3697 *priv;
+	int control_bank;
+};
+
+/**
+ * struct lm3697 -
+ * @enable_gpio - Hardware enable gpio
+ * @regulator - LED supply regulator pointer
+ * @client - Pointer to the I2C client
+ * @regmap - Devices register map
+ * @dev - Pointer to the devices device struct
+ * @lock - Lock for reading/writing the device
+ * @leds - Array of LED strings.
+ */
+struct lm3697 {
+	struct gpio_desc *enable_gpio;
+	struct regulator *regulator;
+	struct i2c_client *client;
+	struct regmap *regmap;
+	struct device *dev;
+	struct mutex lock;
+	struct lm3697_led leds[];
+};
+
+static const struct reg_default lm3697_reg_defs[] = {
+	{LM3697_OUTPUT_CONFIG, 0x6},
+	{LM3697_CTRL_A_RAMP, 0x0},
+	{LM3697_CTRL_B_RAMP, 0x0},
+	{LM3697_CTRL_A_B_RT_RAMP, 0x0},
+	{LM3697_CTRL_A_B_RAMP_CFG, 0x0},
+	{LM3697_CTRL_A_B_BRT_CFG, 0x0},
+	{LM3697_CTRL_A_FS_CURR_CFG, 0x13},
+	{LM3697_CTRL_B_FS_CURR_CFG, 0x13},
+	{LM3697_PWM_CFG, 0xc},
+	{LM3697_CTRL_A_BRT_LSB, 0x0},
+	{LM3697_CTRL_A_BRT_MSB, 0x0},
+	{LM3697_CTRL_B_BRT_LSB, 0x0},
+	{LM3697_CTRL_B_BRT_MSB, 0x0},
+	{LM3697_CTRL_ENABLE, 0x0},
+};
+
+static const struct regmap_config lm3697_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = LM3697_CTRL_ENABLE,
+	.reg_defaults = lm3697_reg_defs,
+	.num_reg_defaults = ARRAY_SIZE(lm3697_reg_defs),
+	.cache_type = REGCACHE_FLAT,
+};
+
+static int lm3697_brightness_set(struct led_classdev *led_cdev,
+				enum led_brightness brt_val)
+{
+	struct lm3697_led *led = container_of(led_cdev, struct lm3697_led,
+					      led_dev);
+	int brt_msb_reg, brt_lsb_reg, ctrl_en_val;
+	int led_brightness_lsb = (brt_val >> 5);
+	int ret;
+
+	mutex_lock(&led->priv->lock);
+
+	if (led->control_bank == LM3697_CONTROL_A) {
+		brt_msb_reg = LM3697_CTRL_A_BRT_MSB;
+		brt_lsb_reg = LM3697_CTRL_A_BRT_LSB;
+		ctrl_en_val = LM3697_CTRL_A_EN;
+	} else {
+		brt_msb_reg = LM3697_CTRL_B_BRT_MSB;
+		brt_lsb_reg = LM3697_CTRL_B_BRT_LSB;
+		ctrl_en_val = LM3697_CTRL_B_EN;
+	}
+
+	if (brt_val == LED_OFF)
+		ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
+					 ctrl_en_val, ~ctrl_en_val);
+	else
+		ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
+					 ctrl_en_val, ctrl_en_val);
+
+	if (ret) {
+		dev_err(&led->priv->client->dev, "Cannot write CTRL enable\n");
+		goto out;
+	}
+
+	ret = regmap_write(led->priv->regmap, brt_lsb_reg, led_brightness_lsb);
+	if (ret) {
+		dev_err(&led->priv->client->dev, "Cannot write LSB\n");
+		goto out;
+	}
+
+	ret = regmap_write(led->priv->regmap, brt_msb_reg, brt_val);
+	if (ret) {
+		dev_err(&led->priv->client->dev, "Cannot write MSB\n");
+		goto out;
+	}
+out:
+	mutex_unlock(&led->priv->lock);
+	return ret;
+}
+
+static int lm3697_set_control_bank(struct lm3697 *priv)
+{
+	u8 control_bank_config = 0;
+	struct lm3697_led *led;
+	int ret, i;
+
+	led = &priv->leds[0];
+	if (led->control_bank == LM3697_CONTROL_A)
+		led = &priv->leds[1];
+
+	for (i = 0; i < LM3697_MAX_LED_STRINGS; i++) {
+		if (led->hvled_strings[i] == LM3697_HVLED_ASSIGNMENT)
+			control_bank_config |= 1 << i;
+	}
+
+	ret = regmap_write(priv->regmap, LM3697_OUTPUT_CONFIG,
+			   control_bank_config);
+	if (ret)
+		dev_err(&priv->client->dev, "Cannot write OUTPUT config\n");
+
+	return ret;
+}
+
+static int lm3697_init(struct lm3697 *priv)
+{
+	int ret;
+
+	if (priv->enable_gpio) {
+		gpiod_direction_output(priv->enable_gpio, 1);
+	} else {
+		ret = regmap_write(priv->regmap, LM3697_RESET, LM3697_SW_RESET);
+		if (ret) {
+			dev_err(&priv->client->dev, "Cannot reset the device\n");
+			goto out;
+		}
+	}
+
+	ret = regmap_write(priv->regmap, LM3697_CTRL_ENABLE, 0x0);
+	if (ret) {
+		dev_err(&priv->client->dev, "Cannot write ctrl enable\n");
+		goto out;
+	}
+
+	ret = lm3697_set_control_bank(priv);
+	if (ret)
+		dev_err(&priv->client->dev, "Setting the CRTL bank failed\n");
+
+out:
+	return ret;
+}
+
+static int lm3697_probe_dt(struct lm3697 *priv)
+{
+	struct fwnode_handle *child = NULL;
+	struct lm3697_led *led;
+	const char *name;
+	int control_bank;
+	size_t i = 0;
+	int ret;
+
+	priv->enable_gpio = devm_gpiod_get_optional(&priv->client->dev,
+						   "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->enable_gpio)) {
+		ret = PTR_ERR(priv->enable_gpio);
+		dev_err(&priv->client->dev, "Failed to get enable gpio: %d\n",
+			ret);
+		return ret;
+	}
+
+	priv->regulator = devm_regulator_get(&priv->client->dev, "vled");
+	if (IS_ERR(priv->regulator))
+		priv->regulator = NULL;
+
+	device_for_each_child_node(priv->dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &control_bank);
+		if (ret) {
+			dev_err(&priv->client->dev, "reg property missing\n");
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		if (control_bank > LM3697_CONTROL_B) {
+			dev_err(&priv->client->dev, "reg property is invalid\n");
+			ret = -EINVAL;
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		led = &priv->leds[i];
+		led->control_bank = control_bank;
+		ret = fwnode_property_read_u32_array(child, "led-sources",
+						    led->hvled_strings,
+						    LM3697_MAX_LED_STRINGS);
+		if (ret) {
+			dev_err(&priv->client->dev, "led-sources property missing\n");
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		fwnode_property_read_string(child, "linux,default-trigger",
+					    &led->led_dev.default_trigger);
+
+		ret = fwnode_property_read_string(child, "label", &name);
+		if (ret)
+			snprintf(led->label, sizeof(led->label),
+				"%s::", priv->client->name);
+		else
+			snprintf(led->label, sizeof(led->label),
+				 "%s:%s", priv->client->name, name);
+
+		led->priv = priv;
+		led->led_dev.name = led->label;
+		led->led_dev.brightness_set_blocking = lm3697_brightness_set;
+
+		ret = devm_led_classdev_register(priv->dev, &led->led_dev);
+		if (ret) {
+			dev_err(&priv->client->dev, "led register err: %d\n",
+				ret);
+			fwnode_handle_put(child);
+			goto child_out;
+		}
+
+		i++;
+	}
+
+child_out:
+	return ret;
+}
+
+static int lm3697_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct lm3697 *led;
+	int count;
+	int ret;
+
+	count = device_get_child_node_count(&client->dev);
+	if (!count) {
+		dev_err(&client->dev, "LEDs are not defined in device tree!");
+		return -ENODEV;
+	}
+
+	led = devm_kzalloc(&client->dev, struct_size(led, leds, count),
+			   GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	mutex_init(&led->lock);
+	i2c_set_clientdata(client, led);
+
+	led->client = client;
+	led->dev = &client->dev;
+	led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
+	if (IS_ERR(led->regmap)) {
+		ret = PTR_ERR(led->regmap);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = lm3697_probe_dt(led);
+	if (ret)
+		return ret;
+
+	return lm3697_init(led);
+}
+
+static int lm3697_remove(struct i2c_client *client)
+{
+	struct lm3697 *led = i2c_get_clientdata(client);
+	int ret;
+
+	ret = regmap_update_bits(led->regmap, LM3697_CTRL_ENABLE,
+				 LM3697_CTRL_A_B_EN, 0);
+	if (ret) {
+		dev_err(&led->client->dev, "Failed to disable the device\n");
+		return ret;
+	}
+
+	if (led->enable_gpio)
+		gpiod_direction_output(led->enable_gpio, 0);
+
+	if (led->regulator) {
+		ret = regulator_disable(led->regulator);
+		if (ret)
+			dev_err(&led->client->dev,
+				"Failed to disable regulator\n");
+	}
+
+	mutex_destroy(&led->lock);
+
+	return 0;
+}
+
+static const struct i2c_device_id lm3697_id[] = {
+	{ "lm3697", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lm3697_id);
+
+static const struct of_device_id of_lm3697_leds_match[] = {
+	{ .compatible = "ti,lm3697", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_lm3697_leds_match);
+
+static struct i2c_driver lm3697_driver = {
+	.driver = {
+		.name	= "lm3697",
+		.of_match_table = of_lm3697_leds_match,
+	},
+	.probe		= lm3697_probe,
+	.remove		= lm3697_remove,
+	.id_table	= lm3697_id,
+};
+module_i2c_driver(lm3697_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LM3697 LED driver");
+MODULE_AUTHOR("Dan Murphy <dmurphy@xxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.17.0.1855.g63749b2dea