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backlight: mp3309c: Add support for MPS MP3309C

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The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a
programmable switching frequency to optimize efficiency.
The brightness can be controlled either by I2C commands (called "analog"
mode) or by a PWM input signal (PWM mode).
This driver supports both modes.

For DT configuration details, please refer to:
- Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml

The datasheet is available at:
- https://www.monolithicpower.com/en/mp3309c.html

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231116105319.957600-3-f.suligoi@asem.it
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Flavio Suligoi 2023-11-16 11:53:19 +01:00 committed by Lee Jones
parent 87f33a1b8f
commit 2e914516a5
4 changed files with 462 additions and 0 deletions
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7
MAINTAINERS
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@ -14658,6 +14658,13 @@ S: Maintained
F: Documentation/driver-api/tty/moxa-smartio.rst
F: drivers/tty/mxser.*
MP3309C BACKLIGHT DRIVER
M: Flavio Suligoi <f.suligoi@asem.it>
L: dri-devel@lists.freedesktop.org
S: Maintained
F: Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml
F: drivers/video/backlight/mp3309c.c
MR800 AVERMEDIA USB FM RADIO DRIVER
M: Alexey Klimov <klimov.linux@gmail.com>
L: linux-media@vger.kernel.org

11
drivers/video/backlight/Kconfig
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@ -402,6 +402,17 @@ config BACKLIGHT_LP8788
help
This supports TI LP8788 backlight driver.
config BACKLIGHT_MP3309C
tristate "Backlight Driver for MPS MP3309C"
depends on I2C && PWM
select REGMAP_I2C
help
This supports MPS MP3309C backlight WLED driver in both PWM and
analog/I2C dimming modes.
To compile this driver as a module, choose M here: the module will
be called mp3309c.
config BACKLIGHT_PANDORA
tristate "Backlight driver for Pandora console"
depends on TWL4030_CORE

1
drivers/video/backlight/Makefile
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@ -44,6 +44,7 @@ obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o
obj-$(CONFIG_BACKLIGHT_LP8788) += lp8788_bl.o
obj-$(CONFIG_BACKLIGHT_LV5207LP) += lv5207lp.o
obj-$(CONFIG_BACKLIGHT_MAX8925) += max8925_bl.o
obj-$(CONFIG_BACKLIGHT_MP3309C) += mp3309c.o
obj-$(CONFIG_BACKLIGHT_MT6370) += mt6370-backlight.o
obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o
obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o

443
drivers/video/backlight/mp3309c.c Normal file
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@ -0,0 +1,443 @@
// 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, *prop_levels;
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");