[PATCH v4 2/2] backlight: mp3309c: Add support for MPS MP3309C
From: Flavio Suligoi
Date: Tue Oct 10 2023 - 08:16:57 EST
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@xxxxxxx>
---
v4:
- add brightness-levels property
- force fixed 32 brightness levels (0..31) in analog-i2c dimming mode
- remove useless irq and reset_gpio from mp3309c_chip structure
v3:
- fix SPDX obsolete spelling
- in mp3309c_bl_update_status, change from msleep_interruptible() to msleep()
and improve the related comment
v2:
- fix dependecies in Kconfig
- fix Kconfig MP3309C entry order
- remove switch-on-delay-ms property
- remove optional gpio property to reset external devices
- remove dimming-mode property (the analog-i2c dimming mode is the default; the
presence of the pwms property, in DT, selects automatically the pwm dimming
mode)
- substitute three boolean properties, used for the overvoltage-protection
values, with a single enum property
- drop simple tracing messages
- use dev_err_probe() in probe function
- change device name from mp3309c_bl to the simple mp3309c
- remove shutdown function
v1:
- first version
MAINTAINERS | 6 +
drivers/video/backlight/Kconfig | 11 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/mp3309c.c | 443 ++++++++++++++++++++++++++++++
4 files changed, 461 insertions(+)
create mode 100644 drivers/video/backlight/mp3309c.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 3be1bdfe8ecc..f779df433af1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14333,6 +14333,12 @@ S: Maintained
F: Documentation/driver-api/tty/moxa-smartio.rst
F: drivers/tty/mxser.*
+MP3309C BACKLIGHT DRIVER
+M: Flavio Suligoi <f.suligoi@xxxxxxx>
+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@xxxxxxxxx>
L: linux-media@xxxxxxxxxxxxxxx
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 51387b1ef012..1144a54a35c0 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -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
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index f72e1c3c59e9..1af583de665b 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -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
diff --git a/drivers/video/backlight/mp3309c.c b/drivers/video/backlight/mp3309c.c
new file mode 100644
index 000000000000..3fe4469ef43f
--- /dev/null
+++ b/drivers/video/backlight/mp3309c.c
@@ -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@xxxxxxx>
+ *
+ * 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@xxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.34.1