leds: lm3692x: Introduce LM3692x dual string driver

Introducing the LM3692x Dual-String white LED driver.

Data sheet is located
http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

3 files changed, 401 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 318a28fd58fe..1d215b39cefd 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -137,6 +137,13 @@ config LEDS_LM3642
           converter plus 1.5A constant current driver for a high-current
           white LED.
 
+config LEDS_LM3692X
+        tristate "LED support for LM3692x Chips"
+        depends on LEDS_CLASS && I2C && OF
+        select REGMAP_I2C
+        help
+          This option enables support for the TI LM3692x family
+          of white LED string drivers used for backlighting.
 
 config LEDS_LOCOMO
         tristate "LED Support for Locomo device"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index a2a6b5a4f86d..987884a5b9a5 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_MLXCPLD)              += leds-mlxcpld.o
 obj-$(CONFIG_LEDS_NIC78BX)              += leds-nic78bx.o
 obj-$(CONFIG_LEDS_MT6323)               += leds-mt6323.o
+obj-$(CONFIG_LEDS_LM3692X)              += leds-lm3692x.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)           += leds-dac124s085.o
diff --git a/drivers/leds/leds-lm3692x.c b/drivers/leds/leds-lm3692x.c
new file mode 100644
index 000000000000..437173d1712c
--- /dev/null
+++ b/drivers/leds/leds-lm3692x.c
@@ -0,0 +1,393 @@
+/*
+ * TI lm3692x LED Driver
+ *
+ * Copyright (C) 2017 Texas Instruments
+ *
+ * Author: Dan Murphy <dmurphy@ti.com>
+ *
+ * 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.
+ *
+ * Data sheet is located
+ * http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf
+ */
+
+#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 LM3692X_REV             0x0
+#define LM3692X_RESET           0x1
+#define LM3692X_EN              0x10
+#define LM3692X_BRT_CTRL        0x11
+#define LM3692X_PWM_CTRL        0x12
+#define LM3692X_BOOST_CTRL      0x13
+#define LM3692X_AUTO_FREQ_HI    0x15
+#define LM3692X_AUTO_FREQ_LO    0x16
+#define LM3692X_BL_ADJ_THRESH   0x17
+#define LM3692X_BRT_LSB         0x18
+#define LM3692X_BRT_MSB         0x19
+#define LM3692X_FAULT_CTRL      0x1e
+#define LM3692X_FAULT_FLAGS     0x1f
+
+#define LM3692X_SW_RESET        BIT(0)
+#define LM3692X_DEVICE_EN       BIT(0)
+#define LM3692X_LED1_EN         BIT(1)
+#define LM3692X_LED2_EN         BIT(2)
+
+/* Brightness Control Bits */
+#define LM3692X_BL_ADJ_POL      BIT(0)
+#define LM3692X_RAMP_RATE_125us 0x00
+#define LM3692X_RAMP_RATE_250us BIT(1)
+#define LM3692X_RAMP_RATE_500us BIT(2)
+#define LM3692X_RAMP_RATE_1ms   (BIT(1) | BIT(2))
+#define LM3692X_RAMP_RATE_2ms   BIT(3)
+#define LM3692X_RAMP_RATE_4ms   (BIT(3) | BIT(1))
+#define LM3692X_RAMP_RATE_8ms   (BIT(2) | BIT(3))
+#define LM3692X_RAMP_RATE_16ms  (BIT(1) | BIT(2) | BIT(3))
+#define LM3692X_RAMP_EN         BIT(4)
+#define LM3692X_BRHT_MODE_REG   0x00
+#define LM3692X_BRHT_MODE_PWM   BIT(5)
+#define LM3692X_BRHT_MODE_MULTI_RAMP BIT(6)
+#define LM3692X_BRHT_MODE_RAMP_MULTI (BIT(5) | BIT(6))
+#define LM3692X_MAP_MODE_EXP    BIT(7)
+
+/* PWM Register Bits */
+#define LM3692X_PWM_FILTER_100  BIT(0)
+#define LM3692X_PWM_FILTER_150  BIT(1)
+#define LM3692X_PWM_FILTER_200  (BIT(0) | BIT(1))
+#define LM3692X_PWM_HYSTER_1LSB BIT(2)
+#define LM3692X_PWM_HYSTER_2LSB BIT(3)
+#define LM3692X_PWM_HYSTER_3LSB (BIT(3) | BIT(2))
+#define LM3692X_PWM_HYSTER_4LSB BIT(4)
+#define LM3692X_PWM_HYSTER_5LSB (BIT(4) | BIT(2))
+#define LM3692X_PWM_HYSTER_6LSB (BIT(4) | BIT(3))
+#define LM3692X_PWM_POLARITY    BIT(5)
+#define LM3692X_PWM_SAMP_4MHZ   BIT(6)
+#define LM3692X_PWM_SAMP_24MHZ  BIT(7)
+
+/* Boost Control Bits */
+#define LM3692X_OCP_PROT_1A     BIT(0)
+#define LM3692X_OCP_PROT_1_25A  BIT(1)
+#define LM3692X_OCP_PROT_1_5A   (BIT(0) | BIT(1))
+#define LM3692X_OVP_21V         BIT(2)
+#define LM3692X_OVP_25V         BIT(3)
+#define LM3692X_OVP_29V         (BIT(2) | BIT(3))
+#define LM3692X_MIN_IND_22UH    BIT(4)
+#define LM3692X_BOOST_SW_1MHZ   BIT(5)
+#define LM3692X_BOOST_SW_NO_SHIFT       BIT(6)
+
+/* Fault Control Bits */
+#define LM3692X_FAULT_CTRL_OVP BIT(0)
+#define LM3692X_FAULT_CTRL_OCP BIT(1)
+#define LM3692X_FAULT_CTRL_TSD BIT(2)
+#define LM3692X_FAULT_CTRL_OPEN BIT(3)
+
+/* Fault Flag Bits */
+#define LM3692X_FAULT_FLAG_OVP BIT(0)
+#define LM3692X_FAULT_FLAG_OCP BIT(1)
+#define LM3692X_FAULT_FLAG_TSD BIT(2)
+#define LM3692X_FAULT_FLAG_SHRT BIT(3)
+#define LM3692X_FAULT_FLAG_OPEN BIT(4)
+
+/**
+ * struct lm3692x_led -
+ * @lock - Lock for reading/writing the device
+ * @client - Pointer to the I2C client
+ * @led_dev - LED class device pointer
+ * @regmap - Devices register map
+ * @enable_gpio - VDDIO/EN gpio to enable communication interface
+ * @regulator - LED supply regulator pointer
+ * @label - LED label
+ */
+struct lm3692x_led {
+        struct mutex lock;
+        struct i2c_client *client;
+        struct led_classdev led_dev;
+        struct regmap *regmap;
+        struct gpio_desc *enable_gpio;
+        struct regulator *regulator;
+        char label[LED_MAX_NAME_SIZE];
+};
+
+static const struct reg_default lm3692x_reg_defs[] = {
+        {LM3692X_EN, 0xf},
+        {LM3692X_BRT_CTRL, 0x61},
+        {LM3692X_PWM_CTRL, 0x73},
+        {LM3692X_BOOST_CTRL, 0x6f},
+        {LM3692X_AUTO_FREQ_HI, 0x0},
+        {LM3692X_AUTO_FREQ_LO, 0x0},
+        {LM3692X_BL_ADJ_THRESH, 0x0},
+        {LM3692X_BRT_LSB, 0x7},
+        {LM3692X_BRT_MSB, 0xff},
+        {LM3692X_FAULT_CTRL, 0x7},
+};
+
+static const struct regmap_config lm3692x_regmap_config = {
+        .reg_bits = 8,
+        .val_bits = 8,
+
+        .max_register = LM3692X_FAULT_FLAGS,
+        .reg_defaults = lm3692x_reg_defs,
+        .num_reg_defaults = ARRAY_SIZE(lm3692x_reg_defs),
+        .cache_type = REGCACHE_RBTREE,
+};
+
+static int lm3692x_fault_check(struct lm3692x_led *led)
+{
+        int ret;
+        unsigned int read_buf;
+
+        ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
+        if (ret)
+                return ret;
+
+        if (read_buf)
+                dev_err(&led->client->dev, "Detected a fault 0x%X\n", read_buf);
+
+        /* The first read may clear the fault.  Check again to see if the fault
+         * still exits and return that value.
+         */
+        regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
+        if (read_buf)
+                dev_err(&led->client->dev, "Second read of fault flags 0x%X\n",
+                        read_buf);
+
+        return read_buf;
+}
+
+static int lm3692x_brightness_set(struct led_classdev *led_cdev,
+                                enum led_brightness brt_val)
+{
+        struct lm3692x_led *led =
+                        container_of(led_cdev, struct lm3692x_led, led_dev);
+        int ret;
+        int led_brightness_lsb = (brt_val >> 5);
+
+        mutex_lock(&led->lock);
+
+        ret = lm3692x_fault_check(led);
+        if (ret) {
+                dev_err(&led->client->dev, "Cannot read/clear faults\n");
+                goto out;
+        }
+
+        ret = regmap_write(led->regmap, LM3692X_BRT_MSB, brt_val);
+        if (ret) {
+                dev_err(&led->client->dev, "Cannot write MSB\n");
+                goto out;
+        }
+
+        ret = regmap_write(led->regmap, LM3692X_BRT_LSB, led_brightness_lsb);
+        if (ret) {
+                dev_err(&led->client->dev, "Cannot write LSB\n");
+                goto out;
+        }
+out:
+        mutex_unlock(&led->lock);
+        return ret;
+}
+
+static int lm3692x_init(struct lm3692x_led *led)
+{
+        int ret;
+
+        if (led->regulator) {
+                ret = regulator_enable(led->regulator);
+                if (ret) {
+                        dev_err(&led->client->dev,
+                                "Failed to enable regulator\n");
+                        return ret;
+                }
+        }
+
+        if (led->enable_gpio)
+                gpiod_direction_output(led->enable_gpio, 1);
+
+        ret = lm3692x_fault_check(led);
+        if (ret) {
+                dev_err(&led->client->dev, "Cannot read/clear faults\n");
+                goto out;
+        }
+
+        ret = regmap_write(led->regmap, LM3692X_BRT_CTRL, 0x00);
+        if (ret)
+                goto out;
+
+        /*
+         * For glitch free operation, the following data should
+         * only be written while device enable bit is 0
+         * per Section 7.5.14 of the data sheet
+         */
+        ret = regmap_write(led->regmap, LM3692X_PWM_CTRL,
+                LM3692X_PWM_FILTER_100 | LM3692X_PWM_SAMP_24MHZ);
+        if (ret)
+                goto out;
+
+        ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL,
+                        LM3692X_BRHT_MODE_RAMP_MULTI |
+                        LM3692X_BL_ADJ_POL |
+                        LM3692X_RAMP_RATE_250us);
+        if (ret)
+                goto out;
+
+        ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
+        if (ret)
+                goto out;
+
+        ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
+        if (ret)
+                goto out;
+
+        ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
+        if (ret)
+                goto out;
+
+        ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
+                        LM3692X_BL_ADJ_POL | LM3692X_PWM_HYSTER_4LSB);
+        if (ret)
+                goto out;
+
+        return ret;
+out:
+        dev_err(&led->client->dev, "Fail writing initialization values\n");
+
+        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");
+        }
+
+        return ret;
+}
+
+static int lm3692x_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        int ret;
+        struct lm3692x_led *led;
+        struct device_node *np = client->dev.of_node;
+        struct device_node *child_node;
+        const char *name;
+
+        led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
+        if (!led)
+                return -ENOMEM;
+
+        for_each_available_child_of_node(np, child_node) {
+                led->led_dev.default_trigger = of_get_property(child_node,
+                                                    "linux,default-trigger",
+                                                    NULL);
+
+                ret = of_property_read_string(child_node, "label", &name);
+                if (!ret)
+                        snprintf(led->label, sizeof(led->label),
+                                 "%s:%s", id->name, name);
+                else
+                        snprintf(led->label, sizeof(led->label),
+                                 "%s::backlight_cluster", id->name);
+        };
+
+        led->enable_gpio = devm_gpiod_get_optional(&client->dev,
+                                                   "enable", GPIOD_OUT_LOW);
+        if (IS_ERR(led->enable_gpio)) {
+                ret = PTR_ERR(led->enable_gpio);
+                dev_err(&client->dev, "Failed to get enable gpio: %d\n", ret);
+                return ret;
+        }
+
+        led->regulator = devm_regulator_get(&client->dev, "vled");
+        if (IS_ERR(led->regulator))
+                led->regulator = NULL;
+
+        led->client = client;
+        led->led_dev.name = led->label;
+        led->led_dev.brightness_set_blocking = lm3692x_brightness_set;
+
+        mutex_init(&led->lock);
+
+        i2c_set_clientdata(client, led);
+
+        led->regmap = devm_regmap_init_i2c(client, &lm3692x_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 = lm3692x_init(led);
+        if (ret)
+                return ret;
+
+        ret = devm_led_classdev_register(&client->dev, &led->led_dev);
+        if (ret) {
+                dev_err(&client->dev, "led register err: %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int lm3692x_remove(struct i2c_client *client)
+{
+        struct lm3692x_led *led = i2c_get_clientdata(client);
+        int 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 lm3692x_id[] = {
+        { "lm36922", 0 },
+        { "lm36923", 1 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, lm3692x_id);
+
+static const struct of_device_id of_lm3692x_leds_match[] = {
+        { .compatible = "ti,lm36922", },
+        { .compatible = "ti,lm36923", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);
+
+static struct i2c_driver lm3692x_driver = {
+        .driver = {
+                .name   = "lm3692x",
+                .of_match_table = of_lm3692x_leds_match,
+        },
+        .probe          = lm3692x_probe,
+        .remove         = lm3692x_remove,
+        .id_table       = lm3692x_id,
+};
+module_i2c_driver(lm3692x_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LM3692X LED driver");
+MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
+MODULE_LICENSE("GPL v2");