linux/drivers/leds/leds-lm3532.c

// SPDX-License-Identifier: GPL-2.0
// TI LM3532 LED driver
// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/

#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include <linux/regmap.h>
#include <linux/types.h>
#include <linux/regulator/consumer.h>
#include <linux/module.h>
#include <uapi/linux/uleds.h>
#include <linux/gpio/consumer.h>

#define LM3532_NAME "lm3532-led"
#define LM3532_BL_MODE_MANUAL	0x00
#define LM3532_BL_MODE_ALS	0x01

#define LM3532_REG_OUTPUT_CFG	0x10
#define LM3532_REG_STARTSHUT_RAMP	0x11
#define LM3532_REG_RT_RAMP	0x12
#define LM3532_REG_PWM_A_CFG	0x13
#define LM3532_REG_PWM_B_CFG	0x14
#define LM3532_REG_PWM_C_CFG	0x15
#define LM3532_REG_ZONE_CFG_A	0x16
#define LM3532_REG_CTRL_A_BRT	0x17
#define LM3532_REG_ZONE_CFG_B	0x18
#define LM3532_REG_CTRL_B_BRT	0x19
#define LM3532_REG_ZONE_CFG_C	0x1a
#define LM3532_REG_CTRL_C_BRT	0x1b
#define LM3532_REG_ENABLE	0x1d
#define LM3532_ALS_CONFIG	0x23
#define LM3532_REG_ZN_0_HI	0x60
#define LM3532_REG_ZN_0_LO	0x61
#define LM3532_REG_ZN_1_HI	0x62
#define LM3532_REG_ZN_1_LO	0x63
#define LM3532_REG_ZN_2_HI	0x64
#define LM3532_REG_ZN_2_LO	0x65
#define LM3532_REG_ZN_3_HI	0x66
#define LM3532_REG_ZN_3_LO	0x67
#define LM3532_REG_MAX		0x7e

/* Contorl Enable */
#define LM3532_CTRL_A_ENABLE	BIT(0)
#define LM3532_CTRL_B_ENABLE	BIT(1)
#define LM3532_CTRL_C_ENABLE	BIT(2)

/* PWM Zone Control */
#define LM3532_PWM_ZONE_MASK	0x7c
#define LM3532_PWM_ZONE_0_EN	BIT(2)
#define LM3532_PWM_ZONE_1_EN	BIT(3)
#define LM3532_PWM_ZONE_2_EN	BIT(4)
#define LM3532_PWM_ZONE_3_EN	BIT(5)
#define LM3532_PWM_ZONE_4_EN	BIT(6)

/* Brightness Configuration */
#define LM3532_I2C_CTRL		BIT(0)
#define LM3532_ALS_CTRL		0
#define LM3532_LINEAR_MAP	BIT(1)
#define LM3532_ZONE_MASK	(BIT(2) | BIT(3) | BIT(4))
#define LM3532_ZONE_0		0
#define LM3532_ZONE_1		BIT(2)
#define LM3532_ZONE_2		BIT(3)
#define LM3532_ZONE_3		(BIT(2) | BIT(3))
#define LM3532_ZONE_4		BIT(4)

#define LM3532_ENABLE_ALS	BIT(3)
#define LM3532_ALS_SEL_SHIFT	6

/* Zone Boundary Register */
#define LM3532_ALS_WINDOW_mV	2000
#define LM3532_ALS_ZB_MAX	4
#define LM3532_ALS_OFFSET_mV	2

#define LM3532_CONTROL_A	0
#define LM3532_CONTROL_B	1
#define LM3532_CONTROL_C	2
#define LM3532_MAX_CONTROL_BANKS 3
#define LM3532_MAX_LED_STRINGS	3

#define LM3532_OUTPUT_CFG_MASK	0x3
#define LM3532_BRT_VAL_ADJUST	8
#define LM3532_RAMP_DOWN_SHIFT	3

#define LM3532_NUM_RAMP_VALS	8
#define LM3532_NUM_AVG_VALS	8
#define LM3532_NUM_IMP_VALS	32

/*
 * struct lm3532_als_data
 * @config - value of ALS configuration register
 * @als1_imp_sel - value of ALS1 resistor select register
 * @als2_imp_sel - value of ALS2 resistor select register
 * @als_avrg_time - ALS averaging time
 * @als_input_mode - ALS input mode for brightness control
 * @als_vmin - Minimum ALS voltage
 * @als_vmax - Maximum ALS voltage
 * @zone_lo - values of ALS lo ZB(Zone Boundary) registers
 * @zone_hi - values of ALS hi ZB(Zone Boundary) registers
 */
struct lm3532_als_data {
	u8 config;
	u8 als1_imp_sel;
	u8 als2_imp_sel;
	u8 als_avrg_time;
	u8 als_input_mode;
	u32 als_vmin;
	u32 als_vmax;
	u8 zones_lo[LM3532_ALS_ZB_MAX];
	u8 zones_hi[LM3532_ALS_ZB_MAX];
};

/**
 * struct lm3532_led
 * @led_dev: led class device
 * @priv - Pointer the device data structure
 * @control_bank - Control bank the LED is associated to
 * @mode - Mode of the LED string
 * @num_leds - Number of LED strings are supported in this array
 * @led_strings - The LED strings supported in this array
 * @label - LED label
 */
struct lm3532_led {
	struct led_classdev led_dev;
	struct lm3532_data *priv;

	int control_bank;
	int mode;
	int num_leds;
	u32 led_strings[LM3532_MAX_CONTROL_BANKS];
	char label[LED_MAX_NAME_SIZE];
};

/**
 * struct lm3532_data
 * @enable_gpio - Hardware enable gpio
 * @regulator: regulator
 * @client: i2c client
 * @regmap - Devices register map
 * @dev - Pointer to the devices device struct
 * @lock - Lock for reading/writing the device
 * @als_data - Pointer to the als data struct
 * @runtime_ramp_up - Runtime ramp up setting
 * @runtime_ramp_down - Runtime ramp down setting
 * @leds - Array of LED strings
 */
struct lm3532_data {
	struct gpio_desc *enable_gpio;
	struct regulator *regulator;
	struct i2c_client *client;
	struct regmap *regmap;
	struct device *dev;
	struct mutex lock;

	struct lm3532_als_data *als_data;

	u32 runtime_ramp_up;
	u32 runtime_ramp_down;

	struct lm3532_led leds[];
};

static const struct reg_default lm3532_reg_defs[] = {
	{LM3532_REG_OUTPUT_CFG, 0xe4},
	{LM3532_REG_STARTSHUT_RAMP, 0xc0},
	{LM3532_REG_RT_RAMP, 0xc0},
	{LM3532_REG_PWM_A_CFG, 0x82},
	{LM3532_REG_PWM_B_CFG, 0x82},
	{LM3532_REG_PWM_C_CFG, 0x82},
	{LM3532_REG_ZONE_CFG_A, 0xf1},
	{LM3532_REG_CTRL_A_BRT, 0xf3},
	{LM3532_REG_ZONE_CFG_B, 0xf1},
	{LM3532_REG_CTRL_B_BRT, 0xf3},
	{LM3532_REG_ZONE_CFG_C, 0xf1},
	{LM3532_REG_CTRL_C_BRT, 0xf3},
	{LM3532_REG_ENABLE, 0xf8},
	{LM3532_ALS_CONFIG, 0x44},
	{LM3532_REG_ZN_0_HI, 0x35},
	{LM3532_REG_ZN_0_LO, 0x33},
	{LM3532_REG_ZN_1_HI, 0x6a},
	{LM3532_REG_ZN_1_LO, 0x66},
	{LM3532_REG_ZN_2_HI, 0xa1},
	{LM3532_REG_ZN_2_LO, 0x99},
	{LM3532_REG_ZN_3_HI, 0xdc},
	{LM3532_REG_ZN_3_LO, 0xcc},
};

static const struct regmap_config lm3532_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,

	.max_register = LM3532_REG_MAX,
	.reg_defaults = lm3532_reg_defs,
	.num_reg_defaults = ARRAY_SIZE(lm3532_reg_defs),
	.cache_type = REGCACHE_FLAT,
};

const static int als_imp_table[LM3532_NUM_IMP_VALS] = {37000, 18500, 12330,
						       92500, 7400, 6170, 5290,
						       4630, 4110, 3700, 3360,
						       3080, 2850, 2640, 2440,
						       2310, 2180, 2060, 1950,
						       1850, 1760, 1680, 1610,
						       1540, 1480, 1420, 1370,
						       1320, 1280, 1230, 1190};
static int lm3532_get_als_imp_index(int als_imped)
{
	int i;

	if (als_imped > als_imp_table[1])
		return 0;

	if (als_imped < als_imp_table[LM3532_NUM_IMP_VALS - 1])
		return LM3532_NUM_IMP_VALS - 1;

	for (i = 1; i < LM3532_NUM_IMP_VALS; i++) {
		if (als_imped == als_imp_table[i])
			return i;

		/* Find an approximate index by looking up the table */
		if (als_imped < als_imp_table[i - 1] &&
		    als_imped > als_imp_table[i]) {
			if (als_imped - als_imp_table[i - 1] <
			    als_imp_table[i] - als_imped)
				return i + 1;
			else
				return i;
		}
	}

	return -EINVAL;
}

static int lm3532_get_index(const int table[], int size, int value)
{
	int i;

	for (i = 1; i < size; i++) {
		if (value == table[i])
			return i;

		/* Find an approximate index by looking up the table */
		if (value > table[i - 1] &&
		    value < table[i]) {
			if (value - table[i - 1] < table[i] - value)
				return i - 1;
			else
				return i;
		}
	}

	return -EINVAL;
}

const static int als_avrg_table[LM3532_NUM_AVG_VALS] = {17920, 35840, 71680,
							1433360, 286720, 573440,
							1146880, 2293760};
static int lm3532_get_als_avg_index(int avg_time)
{
	if (avg_time <= als_avrg_table[0])
		return 0;

	if (avg_time > als_avrg_table[LM3532_NUM_AVG_VALS - 1])
		return LM3532_NUM_AVG_VALS - 1;

	return lm3532_get_index(&als_avrg_table[0], LM3532_NUM_AVG_VALS,
				avg_time);
}

const static int ramp_table[LM3532_NUM_RAMP_VALS] = { 8, 1024, 2048, 4096, 8192,
						     16384, 32768, 65536};
static int lm3532_get_ramp_index(int ramp_time)
{
	if (ramp_time <= ramp_table[0])
		return 0;

	if (ramp_time > ramp_table[LM3532_NUM_RAMP_VALS - 1])
		return LM3532_NUM_RAMP_VALS - 1;

	return lm3532_get_index(&ramp_table[0], LM3532_NUM_RAMP_VALS,
				ramp_time);
}

static int lm3532_led_enable(struct lm3532_led *led_data)
{
	int ctrl_en_val = BIT(led_data->control_bank);
	int ret;

	ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,
					 ctrl_en_val, ctrl_en_val);
	if (ret) {
		dev_err(led_data->priv->dev, "Failed to set ctrl:%d\n", ret);
		return ret;
	}

	return regulator_enable(led_data->priv->regulator);
}

static int lm3532_led_disable(struct lm3532_led *led_data)
{
	int ctrl_en_val = BIT(led_data->control_bank);
	int ret;

	ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,
					 ctrl_en_val, ~ctrl_en_val);
	if (ret) {
		dev_err(led_data->priv->dev, "Failed to set ctrl:%d\n", ret);
		return ret;
	}

	return regulator_disable(led_data->priv->regulator);
}

static int lm3532_brightness_set(struct led_classdev *led_cdev,
				 enum led_brightness brt_val)
{
	struct lm3532_led *led =
			container_of(led_cdev, struct lm3532_led, led_dev);
	u8 brightness_reg;
	int ret;

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

	if (led->mode == LM3532_BL_MODE_ALS) {
		if (brt_val > LED_OFF)
			ret = lm3532_led_enable(led);
		else
			ret = lm3532_led_disable(led);

		goto unlock;
	}

	if (brt_val == LED_OFF) {
		ret = lm3532_led_disable(led);
		goto unlock;
	}

	ret = lm3532_led_enable(led);
	if (ret)
		goto unlock;

	brightness_reg = LM3532_REG_CTRL_A_BRT + led->control_bank * 2;
	brt_val = brt_val / LM3532_BRT_VAL_ADJUST;

	ret = regmap_write(led->priv->regmap, brightness_reg, brt_val);

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

static int lm3532_init_registers(struct lm3532_led *led)
{
	struct lm3532_data *drvdata = led->priv;
	unsigned int runtime_ramp_val;
	unsigned int output_cfg_val = 0;
	unsigned int output_cfg_shift = 0;
	unsigned int output_cfg_mask = 0;
	int ret, i;

	for (i = 0; i < led->num_leds; i++) {
		output_cfg_shift = led->led_strings[i] * 2;
		output_cfg_val |= (led->control_bank << output_cfg_shift);
		output_cfg_mask |= LM3532_OUTPUT_CFG_MASK << output_cfg_shift;
	}

	ret = regmap_update_bits(drvdata->regmap, LM3532_REG_OUTPUT_CFG,
				 output_cfg_mask, output_cfg_val);
	if (ret)
		return ret;

	runtime_ramp_val = drvdata->runtime_ramp_up |
			 (drvdata->runtime_ramp_down << LM3532_RAMP_DOWN_SHIFT);

	return regmap_write(drvdata->regmap, LM3532_REG_RT_RAMP,
			    runtime_ramp_val);
}

static int lm3532_als_configure(struct lm3532_data *priv,
				struct lm3532_led *led)
{
	struct lm3532_als_data *als = priv->als_data;
	u32 als_vmin, als_vmax, als_vstep;
	int zone_reg = LM3532_REG_ZN_0_HI;
	int brightnes_config_reg;
	int ret;
	int i;

	als_vmin = als->als_vmin;
	als_vmax = als->als_vmax;

	als_vstep = (als_vmax - als_vmin) / ((LM3532_ALS_ZB_MAX + 1) * 2);

	for (i = 0; i < LM3532_ALS_ZB_MAX; i++) {
		als->zones_lo[i] = ((als_vmin + als_vstep + (i * als_vstep)) *
				LED_FULL) / 1000;
		als->zones_hi[i] = ((als_vmin + LM3532_ALS_OFFSET_mV +
				als_vstep + (i * als_vstep)) * LED_FULL) / 1000;

		zone_reg = LM3532_REG_ZN_0_HI + i * 2;
		ret = regmap_write(priv->regmap, zone_reg, als->zones_lo[i]);
		if (ret)
			return ret;

		zone_reg += 1;
		ret = regmap_write(priv->regmap, zone_reg, als->zones_hi[i]);
		if (ret)
			return ret;
	}

	als->config = (als->als_avrg_time | (LM3532_ENABLE_ALS) |
		(als->als_input_mode << LM3532_ALS_SEL_SHIFT));

	ret = regmap_write(priv->regmap, LM3532_ALS_CONFIG, als->config);
	if (ret)
		return ret;

	brightnes_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;

	return regmap_update_bits(priv->regmap, brightnes_config_reg,
				  LM3532_I2C_CTRL, LM3532_ALS_CTRL);
}

static int lm3532_parse_als(struct lm3532_data *priv)
{
	struct lm3532_als_data *als;
	int als_avg_time;
	int als_impedance;
	int ret;

	als = devm_kzalloc(priv->dev, sizeof(*als), GFP_KERNEL);
	if (als == NULL)
		return -ENOMEM;

	ret = device_property_read_u32(&priv->client->dev, "ti,als-vmin",
				       &als->als_vmin);
	if (ret)
		als->als_vmin = 0;

	ret = device_property_read_u32(&priv->client->dev, "ti,als-vmax",
				       &als->als_vmax);
	if (ret)
		als->als_vmax = LM3532_ALS_WINDOW_mV;

	if (als->als_vmax > LM3532_ALS_WINDOW_mV) {
		ret = -EINVAL;
		return ret;
	}

	ret = device_property_read_u32(&priv->client->dev, "ti,als1-imp-sel",
				      &als_impedance);
	if (ret)
		als->als1_imp_sel = 0;
	else
		als->als1_imp_sel = lm3532_get_als_imp_index(als_impedance);

	ret = device_property_read_u32(&priv->client->dev, "ti,als2-imp-sel",
				      &als_impedance);
	if (ret)
		als->als2_imp_sel = 0;
	else
		als->als2_imp_sel = lm3532_get_als_imp_index(als_impedance);

	ret = device_property_read_u32(&priv->client->dev, "ti,als-avrg-time-us",
				      &als_avg_time);
	if (ret)
		als->als_avrg_time = 0;
	else
		als->als_avrg_time = lm3532_get_als_avg_index(als_avg_time);

	ret = device_property_read_u8(&priv->client->dev, "ti,als-input-mode",
				      &als->als_input_mode);
	if (ret)
		als->als_input_mode = 0;

	if (als->als_input_mode > LM3532_BL_MODE_ALS) {
		ret = -EINVAL;
		return ret;
	}

	priv->als_data = als;

	return ret;
}

static int lm3532_parse_node(struct lm3532_data *priv)
{
	struct fwnode_handle *child = NULL;
	struct lm3532_led *led;
	const char *name;
	int control_bank;
	u32 ramp_time;
	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))
		priv->enable_gpio = NULL;

	priv->regulator = devm_regulator_get(&priv->client->dev, "vin");
	if (IS_ERR(priv->regulator))
		priv->regulator = NULL;

	ret = device_property_read_u32(&priv->client->dev, "ramp-up-us",
				       &ramp_time);
	if (ret)
		dev_info(&priv->client->dev, "ramp-up-ms property missing\n");
	else
		priv->runtime_ramp_up = lm3532_get_ramp_index(ramp_time);

	ret = device_property_read_u32(&priv->client->dev, "ramp-down-us",
				       &ramp_time);
	if (ret)
		dev_info(&priv->client->dev, "ramp-down-ms property missing\n");
	else
		priv->runtime_ramp_down = lm3532_get_ramp_index(ramp_time);

	device_for_each_child_node(priv->dev, child) {
		led = &priv->leds[i];

		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 > LM3532_CONTROL_C) {
			dev_err(&priv->client->dev, "Control bank invalid\n");
			continue;
		}

		led->control_bank = control_bank;

		ret = fwnode_property_read_u32(child, "ti,led-mode",
					       &led->mode);
		if (ret) {
			dev_err(&priv->client->dev, "ti,led-mode property missing\n");
			fwnode_handle_put(child);
			goto child_out;
		}

		if (led->mode == LM3532_BL_MODE_ALS) {
			ret = lm3532_parse_als(priv);
			if (ret)
				dev_err(&priv->client->dev, "Failed to parse als\n");
			else
				lm3532_als_configure(priv, led);
		}

		led->num_leds = fwnode_property_read_u32_array(child,
							       "led-sources",
							       NULL, 0);

		if (led->num_leds > LM3532_MAX_LED_STRINGS) {
			dev_err(&priv->client->dev, "To many LED string defined\n");
			continue;
		}

		ret = fwnode_property_read_u32_array(child, "led-sources",
						    led->led_strings,
						    led->num_leds);
		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 = lm3532_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;
		}

		lm3532_init_registers(led);

		i++;
	}

child_out:
	return ret;
}

static int lm3532_probe(struct i2c_client *client,
			   const struct i2c_device_id *id)
{
	struct lm3532_data *drvdata;
	int ret = 0;
	int count;

	count = device_get_child_node_count(&client->dev);
	if (!count) {
		dev_err(&client->dev, "LEDs are not defined in device tree!");
		return -ENODEV;
	}

	drvdata = devm_kzalloc(&client->dev, struct_size(drvdata, leds, count),
			   GFP_KERNEL);
	if (drvdata == NULL)
		return -ENOMEM;

	drvdata->client = client;
	drvdata->dev = &client->dev;

	drvdata->regmap = devm_regmap_init_i2c(client, &lm3532_regmap_config);
	if (IS_ERR(drvdata->regmap)) {
		ret = PTR_ERR(drvdata->regmap);
		dev_err(&client->dev, "Failed to allocate register map: %d\n",
			ret);
		return ret;
	}

	mutex_init(&drvdata->lock);
	i2c_set_clientdata(client, drvdata);

	ret = lm3532_parse_node(drvdata);
	if (ret) {
		dev_err(&client->dev, "Failed to parse node\n");
		return ret;
	}

	if (drvdata->enable_gpio)
		gpiod_direction_output(drvdata->enable_gpio, 1);

	return ret;
}

static int lm3532_remove(struct i2c_client *client)
{
	struct lm3532_data *drvdata = i2c_get_clientdata(client);

	mutex_destroy(&drvdata->lock);

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

	return 0;
}

static const struct of_device_id of_lm3532_leds_match[] = {
	{ .compatible = "ti,lm3532", },
	{},
};
MODULE_DEVICE_TABLE(of, of_lm3532_leds_match);

static const struct i2c_device_id lm3532_id[] = {
	{LM3532_NAME, 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, lm3532_id);

static struct i2c_driver lm3532_i2c_driver = {
	.probe = lm3532_probe,
	.remove = lm3532_remove,
	.id_table = lm3532_id,
	.driver = {
		.name = LM3532_NAME,
		.of_match_table = of_lm3532_leds_match,
	},
};
module_i2c_driver(lm3532_i2c_driver);

MODULE_DESCRIPTION("Back Light driver for LM3532");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");