// 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 <[email protected]>
*
* Based on pwm_bl.c
*/
#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/property.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:
* - enable/disable synchronous mode
* - set overvoltage protection (OVP)
*/
reg_val = 0x00;
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_might_sleep(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 mp3309c_parse_fwnode(struct mp3309c_chip *chip,
struct mp3309c_platform_data *pdata)
{
int ret, i;
unsigned int tmp_value;
struct device *dev = chip->dev;
int num_levels;
if (!dev_fwnode(dev))
return dev_err_probe(dev, -ENODEV, "failed to get firmware node\n");
/*
* 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;
if (device_property_present(dev, "pwms")) {
chip->pwmd = devm_pwm_get(dev, NULL);
if (IS_ERR(chip->pwmd))
return dev_err_probe(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(dev, "enable", GPIOD_OUT_HIGH);
if (IS_ERR(chip->enable_gpio))
return dev_err_probe(dev, PTR_ERR(chip->enable_gpio),
"error getting enable gpio\n");
} else {
/*
* PWM control mode: check for brightness level in DT
*/
if (device_property_present(dev, "brightness-levels")) {
/* Read brightness levels from DT */
num_levels = device_property_count_u32(dev, "brightness-levels");
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(dev, num_levels, sizeof(*pdata->levels), GFP_KERNEL);
if (!pdata->levels)
return -ENOMEM;
if (device_property_present(dev, "brightness-levels")) {
ret = device_property_read_u32_array(dev, "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 = device_property_read_u32(dev, "default-brightness", &pdata->default_brightness);
if (ret)
pdata->default_brightness = pdata->max_brightness;
if (pdata->default_brightness > pdata->max_brightness) {
dev_err_probe(dev, -ERANGE, "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;
ret = device_property_read_u32(dev, "mps,overvoltage-protection-microvolt", &tmp_value);
if (!ret) {
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 = !device_property_read_bool(dev, "mps,no-sync-mode");
return 0;
}
static int mp3309c_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct mp3309c_platform_data *pdata = dev_get_platdata(dev);
struct mp3309c_chip *chip;
struct backlight_properties props;
struct pwm_state pwmstate;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return dev_err_probe(dev, -EOPNOTSUPP, "failed to check i2c functionality\n");
chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->dev = dev;
chip->regmap = devm_regmap_init_i2c(client, &mp3309c_regmap);
if (IS_ERR(chip->regmap))
return dev_err_probe(dev, PTR_ERR(chip->regmap),
"failed to allocate register map\n");
i2c_set_clientdata(client, chip);
if (!pdata) {
pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
ret = mp3309c_parse_fwnode(chip, pdata);
if (ret)
return ret;
}
chip->pdata = pdata;
/* Backlight properties */
memset(&props, 0, sizeof(struct backlight_properties));
props.brightness = pdata->default_brightness;
props.max_brightness = pdata->max_brightness;
props.scale = BACKLIGHT_SCALE_LINEAR;
props.type = BACKLIGHT_RAW;
props.power = BACKLIGHT_POWER_ON;
chip->bl = devm_backlight_device_register(dev, "mp3309c", dev, chip,
&mp3309c_bl_ops, &props);
if (IS_ERR(chip->bl))
return dev_err_probe(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_might_sleep(chip->pwmd, &pwmstate);
if (ret)
return dev_err_probe(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 = BACKLIGHT_POWER_OFF;
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" },
{ }
};
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 <[email protected]>");
MODULE_LICENSE("GPL");
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