root/drivers/leds/leds-lm3697.c
// SPDX-License-Identifier: GPL-2.0
// TI LM3697 LED chip family driver
// Copyright (C) 2018 Texas Instruments Incorporated - https://www.ti.com/

#include <linux/bits.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/types.h>

#include <linux/leds-ti-lmu-common.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_MAX_CONTROL_BANKS 2

/**
 * 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
 * @lmu_data: Register and setting values for common code
 * @control_bank: Control bank the LED is associated to. 0 is control bank A
 *                 1 is control bank B
 * @enabled: LED brightness level (or LED_OFF)
 * @num_leds: Number of LEDs available
 */
struct lm3697_led {
        u32 hvled_strings[LM3697_MAX_LED_STRINGS];
        char label[LED_MAX_NAME_SIZE];
        struct led_classdev led_dev;
        struct lm3697 *priv;
        struct ti_lmu_bank lmu_data;
        int control_bank;
        int enabled;
        int num_leds;
};

/**
 * 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
 * @bank_cfg: OUTPUT_CONFIG register values
 * @num_banks: Number of control banks
 */
struct lm3697 {
        struct gpio_desc *enable_gpio;
        struct regulator *regulator;
        struct i2c_client *client;
        struct regmap *regmap;
        struct device *dev;
        struct mutex lock;

        int bank_cfg;
        int num_banks;

        struct lm3697_led leds[] __counted_by(num_banks);
};

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 ctrl_en_val = (1 << led->control_bank);
        struct device *dev = led->priv->dev;
        int ret;

        mutex_lock(&led->priv->lock);

        if (brt_val == LED_OFF) {
                ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
                                         ctrl_en_val, ~ctrl_en_val);
                if (ret) {
                        dev_err(dev, "Cannot write ctrl register\n");
                        goto brightness_out;
                }

                led->enabled = LED_OFF;
        } else {
                ret = ti_lmu_common_set_brightness(&led->lmu_data, brt_val);
                if (ret) {
                        dev_err(dev, "Cannot write brightness\n");
                        goto brightness_out;
                }

                if (!led->enabled) {
                        ret = regmap_update_bits(led->priv->regmap,
                                                 LM3697_CTRL_ENABLE,
                                                 ctrl_en_val, ctrl_en_val);
                        if (ret) {
                                dev_err(dev, "Cannot enable the device\n");
                                goto brightness_out;
                        }

                        led->enabled = brt_val;
                }
        }

brightness_out:
        mutex_unlock(&led->priv->lock);
        return ret;
}

static int lm3697_init(struct lm3697 *priv)
{
        struct device *dev = priv->dev;
        struct lm3697_led *led;
        int i, 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(dev, "Cannot reset the device\n");
                        goto out;
                }
        }

        ret = regmap_write(priv->regmap, LM3697_CTRL_ENABLE, 0x0);
        if (ret) {
                dev_err(dev, "Cannot write ctrl enable\n");
                goto out;
        }

        ret = regmap_write(priv->regmap, LM3697_OUTPUT_CONFIG, priv->bank_cfg);
        if (ret)
                dev_err(dev, "Cannot write OUTPUT config\n");

        for (i = 0; i < priv->num_banks; i++) {
                led = &priv->leds[i];
                ret = ti_lmu_common_set_ramp(&led->lmu_data);
                if (ret)
                        dev_err(dev, "Setting the ramp rate failed\n");
        }
out:
        return ret;
}

static int lm3697_probe_dt(struct lm3697 *priv)
{
        struct device *dev = priv->dev;
        struct lm3697_led *led;
        int ret = -EINVAL;
        int control_bank;
        size_t i = 0;
        int j;

        priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",
                                                    GPIOD_OUT_LOW);
        if (IS_ERR(priv->enable_gpio))
                return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),
                                          "Failed to get enable GPIO\n");

        priv->regulator = devm_regulator_get(dev, "vled");
        if (IS_ERR(priv->regulator))
                priv->regulator = NULL;

        device_for_each_child_node_scoped(dev, child) {
                struct led_init_data init_data = {};

                ret = fwnode_property_read_u32(child, "reg", &control_bank);
                if (ret) {
                        dev_err(dev, "reg property missing\n");
                        return ret;
                }

                if (control_bank > LM3697_CONTROL_B) {
                        dev_err(dev, "reg property is invalid\n");
                        return -EINVAL;
                }

                led = &priv->leds[i];

                ret = ti_lmu_common_get_brt_res(dev, child, &led->lmu_data);
                if (ret)
                        dev_warn(dev,
                                 "brightness resolution property missing\n");

                led->control_bank = control_bank;
                led->lmu_data.regmap = priv->regmap;
                led->lmu_data.runtime_ramp_reg = LM3697_CTRL_A_RAMP +
                                                 control_bank;
                led->lmu_data.msb_brightness_reg = LM3697_CTRL_A_BRT_MSB +
                                                   led->control_bank * 2;
                led->lmu_data.lsb_brightness_reg = LM3697_CTRL_A_BRT_LSB +
                                                   led->control_bank * 2;

                led->num_leds = fwnode_property_count_u32(child, "led-sources");
                if (led->num_leds > LM3697_MAX_LED_STRINGS) {
                        dev_err(dev, "Too many LED strings defined\n");
                        continue;
                }

                ret = fwnode_property_read_u32_array(child, "led-sources",
                                                    led->hvled_strings,
                                                    led->num_leds);
                if (ret) {
                        dev_err(dev, "led-sources property missing\n");
                        return ret;
                }

                for (j = 0; j < led->num_leds; j++)
                        priv->bank_cfg |=
                                (led->control_bank << led->hvled_strings[j]);

                ret = ti_lmu_common_get_ramp_params(dev, child, &led->lmu_data);
                if (ret)
                        dev_warn(dev, "runtime-ramp properties missing\n");

                init_data.fwnode = child;
                init_data.devicename = priv->client->name;
                /* for backwards compatibility if `label` is not present */
                init_data.default_label = ":";

                led->priv = priv;
                led->led_dev.max_brightness = led->lmu_data.max_brightness;
                led->led_dev.brightness_set_blocking = lm3697_brightness_set;

                ret = devm_led_classdev_register_ext(dev, &led->led_dev,
                                                     &init_data);
                if (ret) {
                        dev_err(dev, "led register err: %d\n", ret);
                        return ret;
                }

                i++;
        }

        return 0;
}

static int lm3697_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct lm3697 *led;
        int count;
        int ret;

        count = device_get_child_node_count(dev);
        if (!count || count > LM3697_MAX_CONTROL_BANKS) {
                dev_err(dev, "Strange device tree!");
                return -ENODEV;
        }

        led = devm_kzalloc(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 = dev;
        led->num_banks = count;
        led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
        if (IS_ERR(led->regmap)) {
                ret = PTR_ERR(led->regmap);
                dev_err(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 void lm3697_remove(struct i2c_client *client)
{
        struct lm3697 *led = i2c_get_clientdata(client);
        struct device *dev = &led->client->dev;
        int ret;

        ret = regmap_update_bits(led->regmap, LM3697_CTRL_ENABLE,
                                 LM3697_CTRL_A_B_EN, 0);
        if (ret)
                dev_err(dev, "Failed to disable the device\n");

        if (led->enable_gpio)
                gpiod_direction_output(led->enable_gpio, 0);

        if (led->regulator) {
                ret = regulator_disable(led->regulator);
                if (ret)
                        dev_err(dev, "Failed to disable regulator\n");
        }

        mutex_destroy(&led->lock);
}

static const struct i2c_device_id lm3697_id[] = {
        { "lm3697" },
        { }
};
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@ti.com>");
MODULE_LICENSE("GPL v2");