diff options
Diffstat (limited to 'drivers/video/backlight/mp3309c.c')
| -rw-r--r-- | drivers/video/backlight/mp3309c.c | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/drivers/video/backlight/mp3309c.c b/drivers/video/backlight/mp3309c.c new file mode 100644 index 0000000000..34d71259fa --- /dev/null +++ b/drivers/video/backlight/mp3309c.c @@ -0,0 +1,444 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for MPS MP3309C White LED driver with I2C interface + * + * This driver support both analog (by I2C commands) and PWM dimming control + * modes. + * + * Copyright (C) 2023 ASEM Srl + * Author: Flavio Suligoi <f.suligoi@asem.it> + * + * Based on pwm_bl.c + */ + +#include <linux/backlight.h> +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/pwm.h> +#include <linux/regmap.h> + +#define REG_I2C_0 0x00 +#define REG_I2C_1 0x01 + +#define REG_I2C_0_EN 0x80 +#define REG_I2C_0_D0 0x40 +#define REG_I2C_0_D1 0x20 +#define REG_I2C_0_D2 0x10 +#define REG_I2C_0_D3 0x08 +#define REG_I2C_0_D4 0x04 +#define REG_I2C_0_RSRV1 0x02 +#define REG_I2C_0_RSRV2 0x01 + +#define REG_I2C_1_RSRV1 0x80 +#define REG_I2C_1_DIMS 0x40 +#define REG_I2C_1_SYNC 0x20 +#define REG_I2C_1_OVP0 0x10 +#define REG_I2C_1_OVP1 0x08 +#define REG_I2C_1_VOS 0x04 +#define REG_I2C_1_LEDO 0x02 +#define REG_I2C_1_OTP 0x01 + +#define ANALOG_I2C_NUM_LEVELS 32 /* 0..31 */ +#define ANALOG_I2C_REG_MASK 0x7c + +#define MP3309C_PWM_DEFAULT_NUM_LEVELS 256 /* 0..255 */ + +enum mp3309c_status_value { + FIRST_POWER_ON, + BACKLIGHT_OFF, + BACKLIGHT_ON, +}; + +enum mp3309c_dimming_mode_value { + DIMMING_PWM, + DIMMING_ANALOG_I2C, +}; + +struct mp3309c_platform_data { + unsigned int max_brightness; + unsigned int default_brightness; + unsigned int *levels; + u8 dimming_mode; + u8 over_voltage_protection; + bool sync_mode; + u8 status; +}; + +struct mp3309c_chip { + struct device *dev; + struct mp3309c_platform_data *pdata; + struct backlight_device *bl; + struct gpio_desc *enable_gpio; + struct regmap *regmap; + struct pwm_device *pwmd; +}; + +static const struct regmap_config mp3309c_regmap = { + .name = "mp3309c_regmap", + .reg_bits = 8, + .reg_stride = 1, + .val_bits = 8, + .max_register = REG_I2C_1, +}; + +static int mp3309c_enable_device(struct mp3309c_chip *chip) +{ + u8 reg_val; + int ret; + + /* I2C register #0 - Device enable */ + ret = regmap_update_bits(chip->regmap, REG_I2C_0, REG_I2C_0_EN, + REG_I2C_0_EN); + if (ret) + return ret; + + /* + * I2C register #1 - Set working mode: + * - set one of the two dimming mode: + * - PWM dimming using an external PWM dimming signal + * - analog dimming using I2C commands + * - enable/disable synchronous mode + * - set overvoltage protection (OVP) + */ + reg_val = 0x00; + if (chip->pdata->dimming_mode == DIMMING_PWM) + reg_val |= REG_I2C_1_DIMS; + if (chip->pdata->sync_mode) + reg_val |= REG_I2C_1_SYNC; + reg_val |= chip->pdata->over_voltage_protection; + ret = regmap_write(chip->regmap, REG_I2C_1, reg_val); + if (ret) + return ret; + + return 0; +} + +static int mp3309c_bl_update_status(struct backlight_device *bl) +{ + struct mp3309c_chip *chip = bl_get_data(bl); + int brightness = backlight_get_brightness(bl); + struct pwm_state pwmstate; + unsigned int analog_val, bits_val; + int i, ret; + + if (chip->pdata->dimming_mode == DIMMING_PWM) { + /* + * PWM control mode + */ + pwm_get_state(chip->pwmd, &pwmstate); + pwm_set_relative_duty_cycle(&pwmstate, + chip->pdata->levels[brightness], + chip->pdata->levels[chip->pdata->max_brightness]); + pwmstate.enabled = true; + ret = pwm_apply_state(chip->pwmd, &pwmstate); + if (ret) + return ret; + + switch (chip->pdata->status) { + case FIRST_POWER_ON: + case BACKLIGHT_OFF: + /* + * After 20ms of low pwm signal level, the chip turns + * off automatically. In this case, before enabling the + * chip again, we must wait about 10ms for pwm signal to + * stabilize. + */ + if (brightness > 0) { + msleep(10); + mp3309c_enable_device(chip); + chip->pdata->status = BACKLIGHT_ON; + } else { + chip->pdata->status = BACKLIGHT_OFF; + } + break; + case BACKLIGHT_ON: + if (brightness == 0) + chip->pdata->status = BACKLIGHT_OFF; + break; + } + } else { + /* + * Analog (by I2C command) control mode + * + * The first time, before setting brightness, we must enable the + * device + */ + if (chip->pdata->status == FIRST_POWER_ON) + mp3309c_enable_device(chip); + + /* + * Dimming mode I2C command (fixed dimming range 0..31) + * + * The 5 bits of the dimming analog value D4..D0 is allocated + * in the I2C register #0, in the following way: + * + * +--+--+--+--+--+--+--+--+ + * |EN|D0|D1|D2|D3|D4|XX|XX| + * +--+--+--+--+--+--+--+--+ + */ + analog_val = brightness; + bits_val = 0; + for (i = 0; i <= 5; i++) + bits_val += ((analog_val >> i) & 0x01) << (6 - i); + ret = regmap_update_bits(chip->regmap, REG_I2C_0, + ANALOG_I2C_REG_MASK, bits_val); + if (ret) + return ret; + + if (brightness > 0) + chip->pdata->status = BACKLIGHT_ON; + else + chip->pdata->status = BACKLIGHT_OFF; + } + + return 0; +} + +static const struct backlight_ops mp3309c_bl_ops = { + .update_status = mp3309c_bl_update_status, +}; + +static int pm3309c_parse_dt_node(struct mp3309c_chip *chip, + struct mp3309c_platform_data *pdata) +{ + struct device_node *node = chip->dev->of_node; + struct property *prop_pwms; + struct property *prop_levels = NULL; + int length = 0; + int ret, i; + unsigned int num_levels, tmp_value; + + if (!node) { + dev_err(chip->dev, "failed to get DT node\n"); + return -ENODEV; + } + + /* + * Dimming mode: the MP3309C provides two dimming control mode: + * + * - PWM mode + * - Analog by I2C control mode (default) + * + * I2C control mode is assumed as default but, if the pwms property is + * found in the backlight node, the mode switches to PWM mode. + */ + pdata->dimming_mode = DIMMING_ANALOG_I2C; + prop_pwms = of_find_property(node, "pwms", &length); + if (prop_pwms) { + chip->pwmd = devm_pwm_get(chip->dev, NULL); + if (IS_ERR(chip->pwmd)) + return dev_err_probe(chip->dev, PTR_ERR(chip->pwmd), + "error getting pwm data\n"); + pdata->dimming_mode = DIMMING_PWM; + pwm_apply_args(chip->pwmd); + } + + /* + * In I2C control mode the dimming levels (0..31) are fixed by the + * hardware, while in PWM control mode they can be chosen by the user, + * to allow nonlinear mappings. + */ + if (pdata->dimming_mode == DIMMING_ANALOG_I2C) { + /* + * Analog (by I2C commands) control mode: fixed 0..31 brightness + * levels + */ + num_levels = ANALOG_I2C_NUM_LEVELS; + + /* Enable GPIO used in I2C dimming mode only */ + chip->enable_gpio = devm_gpiod_get(chip->dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(chip->enable_gpio)) + return dev_err_probe(chip->dev, + PTR_ERR(chip->enable_gpio), + "error getting enable gpio\n"); + } else { + /* + * PWM control mode: check for brightness level in DT + */ + prop_levels = of_find_property(node, "brightness-levels", + &length); + if (prop_levels) { + /* Read brightness levels from DT */ + num_levels = length / sizeof(u32); + if (num_levels < 2) + return -EINVAL; + } else { + /* Use default brightness levels */ + num_levels = MP3309C_PWM_DEFAULT_NUM_LEVELS; + } + } + + /* Fill brightness levels array */ + pdata->levels = devm_kcalloc(chip->dev, num_levels, + sizeof(*pdata->levels), GFP_KERNEL); + if (!pdata->levels) + return -ENOMEM; + if (prop_levels) { + ret = of_property_read_u32_array(node, "brightness-levels", + pdata->levels, + num_levels); + if (ret < 0) + return ret; + } else { + for (i = 0; i < num_levels; i++) + pdata->levels[i] = i; + } + + pdata->max_brightness = num_levels - 1; + + ret = of_property_read_u32(node, "default-brightness", + &pdata->default_brightness); + if (ret) + pdata->default_brightness = pdata->max_brightness; + if (pdata->default_brightness > pdata->max_brightness) { + dev_err(chip->dev, + "default brightness exceeds max brightness\n"); + pdata->default_brightness = pdata->max_brightness; + } + + /* + * Over-voltage protection (OVP) + * + * This (optional) property values are: + * + * - 13.5V + * - 24V + * - 35.5V (hardware default setting) + * + * If missing, the default value for OVP is 35.5V + */ + pdata->over_voltage_protection = REG_I2C_1_OVP1; + if (!of_property_read_u32(node, "mps,overvoltage-protection-microvolt", + &tmp_value)) { + switch (tmp_value) { + case 13500000: + pdata->over_voltage_protection = 0x00; + break; + case 24000000: + pdata->over_voltage_protection = REG_I2C_1_OVP0; + break; + case 35500000: + pdata->over_voltage_protection = REG_I2C_1_OVP1; + break; + default: + return -EINVAL; + } + } + + /* Synchronous (default) and non-synchronous mode */ + pdata->sync_mode = true; + if (of_property_read_bool(node, "mps,no-sync-mode")) + pdata->sync_mode = false; + + return 0; +} + +static int mp3309c_probe(struct i2c_client *client) +{ + struct mp3309c_platform_data *pdata = dev_get_platdata(&client->dev); + struct mp3309c_chip *chip; + struct backlight_properties props; + struct pwm_state pwmstate; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_err(&client->dev, "failed to check i2c functionality\n"); + return -EOPNOTSUPP; + } + + chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->dev = &client->dev; + + chip->regmap = devm_regmap_init_i2c(client, &mp3309c_regmap); + if (IS_ERR(chip->regmap)) + return dev_err_probe(&client->dev, PTR_ERR(chip->regmap), + "failed to allocate register map\n"); + + i2c_set_clientdata(client, chip); + + if (!pdata) { + pdata = devm_kzalloc(chip->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + ret = pm3309c_parse_dt_node(chip, pdata); + if (ret) + return ret; + } + chip->pdata = pdata; + + /* Backlight properties */ + props.brightness = pdata->default_brightness; + props.max_brightness = pdata->max_brightness; + props.scale = BACKLIGHT_SCALE_LINEAR; + props.type = BACKLIGHT_RAW; + props.power = FB_BLANK_UNBLANK; + props.fb_blank = FB_BLANK_UNBLANK; + chip->bl = devm_backlight_device_register(chip->dev, "mp3309c", + chip->dev, chip, + &mp3309c_bl_ops, &props); + if (IS_ERR(chip->bl)) + return dev_err_probe(chip->dev, PTR_ERR(chip->bl), + "error registering backlight device\n"); + + /* In PWM dimming mode, enable pwm device */ + if (chip->pdata->dimming_mode == DIMMING_PWM) { + pwm_init_state(chip->pwmd, &pwmstate); + pwm_set_relative_duty_cycle(&pwmstate, + chip->pdata->default_brightness, + chip->pdata->max_brightness); + pwmstate.enabled = true; + ret = pwm_apply_state(chip->pwmd, &pwmstate); + if (ret) + return dev_err_probe(chip->dev, ret, + "error setting pwm device\n"); + } + + chip->pdata->status = FIRST_POWER_ON; + backlight_update_status(chip->bl); + + return 0; +} + +static void mp3309c_remove(struct i2c_client *client) +{ + struct mp3309c_chip *chip = i2c_get_clientdata(client); + struct backlight_device *bl = chip->bl; + + bl->props.power = FB_BLANK_POWERDOWN; + bl->props.brightness = 0; + backlight_update_status(chip->bl); +} + +static const struct of_device_id mp3309c_match_table[] = { + { .compatible = "mps,mp3309c", }, + { }, +}; +MODULE_DEVICE_TABLE(of, mp3309c_match_table); + +static const struct i2c_device_id mp3309c_id[] = { + { "mp3309c", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mp3309c_id); + +static struct i2c_driver mp3309c_i2c_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = mp3309c_match_table, + }, + .probe = mp3309c_probe, + .remove = mp3309c_remove, + .id_table = mp3309c_id, +}; + +module_i2c_driver(mp3309c_i2c_driver); + +MODULE_DESCRIPTION("Backlight Driver for MPS MP3309C"); +MODULE_AUTHOR("Flavio Suligoi <f.suligoi@asem.it>"); +MODULE_LICENSE("GPL"); |