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Message-Id: <20230829101546.483189-2-f.suligoi@asem.it>
Date: Tue, 29 Aug 2023 12:15:46 +0200
From: Flavio Suligoi <f.suligoi@...m.it>
To: Lee Jones <lee@...nel.org>,
Daniel Thompson <daniel.thompson@...aro.org>,
Jingoo Han <jingoohan1@...il.com>,
Helge Deller <deller@....de>, Pavel Machek <pavel@....cz>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>
Cc: dri-devel@...ts.freedesktop.org, linux-leds@...r.kernel.org,
devicetree@...r.kernel.org, linux-fbdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Flavio Suligoi <f.suligoi@...m.it>
Subject: [PATCH v1 2/2] backlight: mp3309c: Add support for MPS MP3309C
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@...m.it>
---
MAINTAINERS | 6 +
drivers/video/backlight/Kconfig | 13 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/mp3309c_bl.c | 491 +++++++++++++++++++++++++++
4 files changed, 511 insertions(+)
create mode 100644 drivers/video/backlight/mp3309c_bl.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 3be1bdfe8ecc..895c56ff4f1e 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@...m.it>
+S: Maintained
+F: Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml
+F: drivers/video/backlight/mp3309c_bl.c
+
MR800 AVERMEDIA USB FM RADIO DRIVER
M: Alexey Klimov <klimov.linux@...il.com>
L: linux-media@...r.kernel.org
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 51387b1ef012..65d0ac9f611d 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -389,6 +389,19 @@ config BACKLIGHT_LM3639
help
This supports TI LM3639 Backlight + 1.5A Flash LED Driver
+config BACKLIGHT_MP3309C
+ tristate "Backlight Driver for MPS MP3309C"
+ depends on I2C
+ select REGMAP_I2C
+ select NEW_LEDS
+ select LEDS_CLASS
+ 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_bl.
+
config BACKLIGHT_LP855X
tristate "Backlight driver for TI LP855X"
depends on I2C && PWM
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index f72e1c3c59e9..c42c5bccc5ac 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-$(CONFIG_BACKLIGHT_MP3309C) += mp3309c_bl.o
obj-$(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_bl.c b/drivers/video/backlight/mp3309c_bl.c
new file mode 100644
index 000000000000..7cb7a542ceca
--- /dev/null
+++ b/drivers/video/backlight/mp3309c_bl.c
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for MPS MP3309C White LED driver with I2C interface
+ *
+ * Copyright (C) 2023 ASEM Srl
+ * Author: Flavio Suligoi <f.suligoi@...m.it>
+ */
+
+#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>
+#include <linux/workqueue.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_MAX_VAL 31
+#define ANALOG_REG_MASK 0x7c
+
+enum backlight_status {
+ FIRST_POWER_ON,
+ BACKLIGHT_OFF,
+ BACKLIGHT_ON,
+};
+
+enum dimming_mode_value {
+ DIMMING_PWM,
+ DIMMING_ANALOG_I2C,
+};
+
+struct mp3309c_platform_data {
+ u32 max_brightness;
+ u32 brightness;
+ u32 switch_on_delay_ms;
+ u32 switch_off_delay_ms;
+ u32 reset_on_delay_ms;
+ u32 reset_on_length_ms;
+ u8 dimming_mode;
+ u8 reset_pulse_enable;
+ u8 over_voltage_protection;
+
+ unsigned int 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;
+
+ struct delayed_work enable_work;
+ struct delayed_work reset_gpio_work;
+ int irq;
+
+ struct gpio_desc *reset_gpio;
+};
+
+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 pm3309c_parse_dt_node(struct mp3309c_chip *chip,
+ struct mp3309c_platform_data *pdata)
+{
+ struct device_node *node = chip->dev->of_node;
+ const char *tmp_string;
+ int ret;
+
+ if (!node) {
+ dev_err(chip->dev, "failed to get DT node\n");
+ return -ENODEV;
+ }
+
+ /*
+ * Dimming mode: the MP3309C provides two dimming methods:
+ *
+ * - PWM mode
+ * - Analog by I2C control mode
+ */
+ ret = of_property_read_string(node, "mps,dimming-mode", &tmp_string);
+ if (ret < 0) {
+ dev_err(chip->dev, "missed dimming-mode in DT\n");
+ return ret;
+ }
+ if (!strcmp(tmp_string, "pwm")) {
+ dev_info(chip->dev, "dimming method: PWM\n");
+ pdata->dimming_mode = DIMMING_PWM;
+ }
+ if (!strcmp(tmp_string, "analog-i2c")) {
+ dev_info(chip->dev, "dimming method: analog by I2C commands\n");
+ pdata->dimming_mode = DIMMING_ANALOG_I2C;
+ }
+
+ /* PWM steps (levels): 0 .. max_brightness */
+ ret = of_property_read_u32(node, "max-brightness",
+ &pdata->max_brightness);
+ if (ret < 0) {
+ dev_err(chip->dev, "failed to get max-brightness from DT\n");
+ return ret;
+ }
+
+ /* Default brightness at startup */
+ ret = of_property_read_u32(node, "default-brightness",
+ &pdata->brightness);
+ if (ret < 0) {
+ dev_err(chip->dev,
+ "failed to get default-brightness from DT\n");
+ return ret;
+ }
+
+ /*
+ * Optional backlight switch-on/off delay
+ *
+ * Note: set 10ms as minimal value for switch-on delay, to stabilize
+ * video data
+ */
+ pdata->switch_on_delay_ms = 50;
+ of_property_read_u32(node, "mps,switch-on-delay-ms",
+ &pdata->switch_on_delay_ms);
+ if (pdata->switch_on_delay_ms < 10) {
+ pdata->switch_on_delay_ms = 10;
+ dev_warn(chip->dev,
+ "switch-on-delay-ms set to 10ms as minimal value\n");
+ }
+ pdata->switch_off_delay_ms = 0;
+ of_property_read_u32(node, "mps,switch-off-delay-ms",
+ &pdata->switch_off_delay_ms);
+
+ /*
+ * Reset: GPIO, initial delay and pulse length
+ *
+ * Use this optional GPIO to reset an external device (LCD panel, video
+ * FPGA, etc) when the backlight is switched on
+ */
+ pdata->reset_pulse_enable = 0;
+ chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "mps,reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(chip->reset_gpio)) {
+ ret = PTR_ERR(chip->reset_gpio);
+ dev_err(chip->dev, "error acquiring reset gpio: %d\n", ret);
+ return ret;
+ }
+ if (chip->reset_gpio) {
+ pdata->reset_pulse_enable = 1;
+
+ pdata->reset_on_delay_ms = 10;
+ of_property_read_u32(node, "mps,reset-on-delay-ms",
+ &pdata->reset_on_delay_ms);
+ pdata->reset_on_length_ms = 10;
+ of_property_read_u32(node, "mps,reset-on-length-ms",
+ &pdata->reset_on_length_ms);
+ }
+
+ /*
+ * Over-voltage protection (OVP)
+ *
+ * These (optional) properties are:
+ *
+ * - overvoltage-protection-13v --> OVP point set to 13.5V
+ * - overvoltage-protection-24v --> OVP point set to 24V
+ * - overvoltage-protection-35v --> OVP point set to 35.5V
+ *
+ * If not chosen, the hw default value for OVP is 35.5V
+ */
+ pdata->over_voltage_protection = REG_I2C_1_OVP1;
+ if (of_property_read_bool(node, "mps,overvoltage-protection-13v"))
+ pdata->over_voltage_protection = 0x00;
+ if (of_property_read_bool(node, "mps,overvoltage-protection-24v"))
+ pdata->over_voltage_protection = REG_I2C_1_OVP0;
+ if (of_property_read_bool(node, "mps,overvoltage-protection-35v"))
+ pdata->over_voltage_protection = REG_I2C_1_OVP1;
+
+ return 0;
+}
+
+static int mp3309c_enable_device(struct mp3309c_chip *chip)
+{
+ u8 reg_val = 0; /* Configuration for analog by I2C commands */
+ 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 synchronous mode (fixed for now)
+ * - set overvoltage protection (OVP)
+ */
+ if (chip->pdata->dimming_mode == DIMMING_PWM)
+ reg_val = REG_I2C_1_DIMS;
+ ret = regmap_write(chip->regmap, REG_I2C_1, reg_val | REG_I2C_1_SYNC |
+ chip->pdata->over_voltage_protection);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/* For delayed backlight enabled */
+static void mp3309c_enable(struct work_struct *work)
+{
+ struct mp3309c_chip *chip = container_of(work, struct mp3309c_chip,
+ enable_work.work);
+ if (mp3309c_enable_device(chip))
+ dev_err(chip->dev, "failed writing I2C register\n");
+}
+
+static void mp3309c_reset_gpio(struct work_struct *work)
+{
+ struct mp3309c_chip *chip = container_of(work, struct mp3309c_chip,
+ reset_gpio_work.work);
+
+ if (chip->reset_gpio) {
+ gpiod_set_value_cansleep(chip->reset_gpio, 0);
+ usleep_range(100, 150);
+ gpiod_set_value_cansleep(chip->reset_gpio, 1);
+ usleep_range(chip->pdata->reset_on_length_ms * 1000,
+ (chip->pdata->reset_on_length_ms * 1000) + 100);
+ gpiod_set_value_cansleep(chip->reset_gpio, 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 dimming mode
+ */
+ pwm_init_state(chip->pwmd, &pwmstate);
+ pwm_set_relative_duty_cycle(&pwmstate, brightness,
+ chip->pdata->max_brightness);
+ pwmstate.enabled = true;
+ ret = pwm_apply_state(chip->pwmd, &pwmstate);
+ if (ret)
+ return ret;
+ } else {
+ /*
+ * Analog dimming mode by I2C commands
+ *
+ * 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 = DIV_ROUND_UP(ANALOG_MAX_VAL * brightness,
+ chip->pdata->max_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_REG_MASK, bits_val);
+ if (ret)
+ return ret;
+ }
+
+ if (brightness > 0) {
+ switch (chip->pdata->status) {
+ case FIRST_POWER_ON:
+ /*
+ * Only for the first time, wait for the optional
+ * switch-on delay and then enable the device.
+ * Otherwise enable the backlight immediately.
+ */
+ schedule_delayed_work(&chip->enable_work,
+ msecs_to_jiffies(chip->pdata->switch_on_delay_ms));
+ /*
+ * Optional external device GPIO reset, with
+ * delay pulse length
+ */
+ if (chip->pdata->reset_pulse_enable)
+ schedule_delayed_work(&chip->reset_gpio_work,
+ msecs_to_jiffies(chip->pdata->reset_on_delay_ms));
+ break;
+ case BACKLIGHT_OFF:
+ /* Enable the backlight immediately */
+ if (chip->pdata->reset_pulse_enable)
+ cancel_delayed_work(&chip->reset_gpio_work);
+ mp3309c_enable_device(chip);
+ break;
+ }
+
+ chip->pdata->status = BACKLIGHT_ON;
+ } else {
+ /* Wait for the optional switch-off delay */
+ if (chip->pdata->switch_off_delay_ms > 0) {
+ usleep_range(chip->pdata->switch_off_delay_ms * 1000,
+ (chip->pdata->switch_off_delay_ms + 1) *
+ 1000);
+ }
+
+ chip->pdata->status = BACKLIGHT_OFF;
+ }
+
+ return 0;
+}
+
+static const struct backlight_ops mp3309c_bl_ops = {
+ .update_status = mp3309c_bl_update_status,
+};
+
+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;
+ 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(struct mp3309c_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)) {
+ ret = PTR_ERR(chip->regmap);
+ dev_err(&client->dev, "failed to allocate register map\n");
+ return ret;
+ }
+
+ i2c_set_clientdata(client, chip);
+
+ if (!pdata) {
+ pdata = devm_kzalloc(chip->dev,
+ sizeof(struct mp3309c_platform_data),
+ GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ ret = pm3309c_parse_dt_node(chip, pdata);
+ if (ret) {
+ dev_err(&client->dev, "failed parsing DT node\n");
+ return ret;
+ }
+ }
+ chip->pdata = pdata;
+
+ chip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(chip->enable_gpio)) {
+ ret = PTR_ERR(chip->enable_gpio);
+ return ret;
+ }
+
+ /* Backlight */
+ props.type = BACKLIGHT_RAW;
+ props.brightness = pdata->brightness;
+ props.max_brightness = pdata->max_brightness;
+ props.scale = BACKLIGHT_SCALE_LINEAR;
+ chip->bl =
+ devm_backlight_device_register(chip->dev, "mp3309c_bl",
+ chip->dev, chip, &mp3309c_bl_ops,
+ &props);
+ if (IS_ERR(chip->bl)) {
+ dev_err(&client->dev, "failed registering backlight\n");
+ return PTR_ERR(chip->bl);
+ }
+ pdata->status = FIRST_POWER_ON;
+
+ /* Enable PWM, if required */
+ if (pdata->dimming_mode == DIMMING_PWM) {
+ chip->pwmd = devm_pwm_get(chip->dev, NULL);
+ if (IS_ERR(chip->pwmd)) {
+ dev_err(&client->dev, "failed getting pwm device\n");
+ return PTR_ERR(chip->pwmd);
+ }
+ pwm_apply_args(chip->pwmd);
+ }
+
+ /*
+ * Workqueue for delayed backlight enabling
+ */
+ INIT_DELAYED_WORK(&chip->enable_work, mp3309c_enable);
+
+ /*
+ * Workqueue for (optional) external device GPIO reset
+ */
+ if (pdata->reset_pulse_enable) {
+ dev_info(&client->dev, "reset pulse enabled\n");
+ INIT_DELAYED_WORK(&chip->reset_gpio_work, mp3309c_reset_gpio);
+ }
+
+ dev_info(&client->dev, "MP3309C backlight initialized");
+ return 0;
+}
+
+static int mp3309c_backlight_switch_off(struct pwm_device *pwmd)
+{
+ struct pwm_state pwmstate;
+
+ /* Switch-off the backlight */
+ pwm_get_state(pwmd, &pwmstate);
+ pwmstate.duty_cycle = 0;
+ pwmstate.enabled = false;
+ pwm_apply_state(pwmd, &pwmstate);
+
+ return 0;
+}
+
+static void mp3309c_remove(struct i2c_client *client)
+{
+ struct mp3309c_chip *chip = i2c_get_clientdata(client);
+
+ if (chip->pdata->dimming_mode == DIMMING_PWM)
+ mp3309c_backlight_switch_off(chip->pwmd);
+ if (chip->pdata->reset_pulse_enable)
+ cancel_delayed_work(&chip->reset_gpio_work);
+}
+
+static void mp3309c_shutdown(struct i2c_client *client)
+{
+ struct mp3309c_chip *chip = i2c_get_clientdata(client);
+
+ if (chip->pdata->dimming_mode == DIMMING_PWM)
+ mp3309c_backlight_switch_off(chip->pwmd);
+}
+
+static const struct of_device_id mp3309c_match_table[] = {
+ { .compatible = "mps,mp3309c-backlight", },
+ { },
+};
+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 = "mp3309c-backlight",
+ .of_match_table = mp3309c_match_table,
+ },
+ .probe = mp3309c_probe,
+ .remove = mp3309c_remove,
+ .shutdown = mp3309c_shutdown,
+ .id_table = mp3309c_id,
+};
+
+module_i2c_driver(mp3309c_i2c_driver);
+
+MODULE_DESCRIPTION("Backlight Driver for MPS MP3309C");
+MODULE_AUTHOR("Flavio Suligoi <f.suligoi@...m.it>");
+MODULE_LICENSE("GPL");
--
2.34.1
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