On 29/08/2023 12:15, Flavio Suligoi wrote:

Why is this placed between LM and LP entries? Keep things ordered.

+	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

This should be just before probe function. It is part of probe path.

+{
+	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");

Drop

+		pdata->dimming_mode = DIMMING_PWM;
+	}
+	if (!strcmp(tmp_string, "analog-i2c")) {
+		dev_info(chip->dev, "dimming method: analog by I2C commands\n");

Drop

+		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;

You miss constraints in the bindings.

+		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;

return dev_err_probe()

+	}
+	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 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),

sizeof(*)

+			    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");

Are you sure regmap allocation should be followed by error message?
Allocations must not... so if this is not allocation, then syntax is:

return dev_err_probe()

+		return ret;
+	}
+
+	i2c_set_clientdata(client, chip);
+
+	if (!pdata) {
+		pdata = devm_kzalloc(chip->dev,
+				     sizeof(struct mp3309c_platform_data),

sizeof(*)

+				     GFP_KERNEL);
+		if (!pdata)
+			return -ENOMEM;
+
+		ret = pm3309c_parse_dt_node(chip, pdata);
+		if (ret) {
+			dev_err(&client->dev, "failed parsing DT node\n");

Why do you print errors multiple times? parse_dt_node already does it.

+			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;

return dev_err_probe()

+	}
+
+	/* 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);

return dev_err_probe()

+	}
+	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);

return dev_err_probe()

+		}
+		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");

Drop, not really helpful.

+		INIT_DELAYED_WORK(&chip->reset_gpio_work, mp3309c_reset_gpio);
+	}
+
+	dev_info(&client->dev, "MP3309C backlight initialized");

Drop simple tracing messages.

+	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);

Why do you need shutdown function?

+}
+
+static const struct of_device_id mp3309c_match_table[] = {
+	{ .compatible = "mps,mp3309c-backlight", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mp3309c_match_table);
+

Best regards,
Krzysztof