pwm-backlight: Add rudimentary device tree support (3e3ed6cd) · Commits · e / devices / android_kernel_oneplus_sm8150

Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt

0 → 100644

+28 −0

Original line number	Original line	Diff line number	Diff line
			pwm-backlight bindings

			Required properties:
			- compatible: "pwm-backlight"
			- pwms: OF device-tree PWM specification (see PWM binding[0])
			- brightness-levels: Array of distinct brightness levels. Typically these
			are in the range from 0 to 255, but any range starting at 0 will do.
			The actual brightness level (PWM duty cycle) will be interpolated
			from these values. 0 means a 0% duty cycle (darkest/off), while the
			last value in the array represents a 100% duty cycle (brightest).
			- default-brightness-level: the default brightness level (index into the
			array defined by the "brightness-levels" property)

			Optional properties:
			- pwm-names: a list of names for the PWM devices specified in the
			"pwms" property (see PWM binding[0])

			[0]: Documentation/devicetree/bindings/pwm/pwm.txt

			Example:

			backlight {
			compatible = "pwm-backlight";
			pwms = <&pwm 0 5000000>;

			brightness-levels = <0 4 8 16 32 64 128 255>;
			default-brightness-level = <6>;
			};

drivers/video/backlight/Kconfig

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -245,7 +245,7 @@ config BACKLIGHT_CARILLO_RANCH

	config BACKLIGHT_PWM		config BACKLIGHT_PWM
	tristate "Generic PWM based Backlight Driver"		tristate "Generic PWM based Backlight Driver"
	depends on HAVE_PWM		depends on PWM
	help		help
	If you have a LCD backlight adjustable by PWM, say Y to enable		If you have a LCD backlight adjustable by PWM, say Y to enable
	this driver.		this driver.

drivers/video/backlight/pwm_bl.c

+129 −20

Original line number	Original line	Diff line number	Diff line
	@@ -26,11 +26,13 @@ struct pwm_bl_data {
	struct device *dev;		struct device *dev;
	unsigned int period;		unsigned int period;
	unsigned int lth_brightness;		unsigned int lth_brightness;
			unsigned int *levels;
	int (notify)(struct device ,		int (notify)(struct device ,
	int brightness);		int brightness);
	void (notify_after)(struct device ,		void (notify_after)(struct device ,
	int brightness);		int brightness);
	int (check_fb)(struct device , struct fb_info *);		int (check_fb)(struct device , struct fb_info *);
			void (exit)(struct device );
	};		};

	static int pwm_backlight_update_status(struct backlight_device *bl)		static int pwm_backlight_update_status(struct backlight_device *bl)
	@@ -52,6 +54,11 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
	pwm_config(pb->pwm, 0, pb->period);		pwm_config(pb->pwm, 0, pb->period);
	pwm_disable(pb->pwm);		pwm_disable(pb->pwm);
	} else {		} else {
			if (pb->levels) {
			brightness = pb->levels[brightness];
			max = pb->levels[max];
			}

	brightness = pb->lth_brightness +		brightness = pb->lth_brightness +
	(brightness * (pb->period - pb->lth_brightness) / max);		(brightness * (pb->period - pb->lth_brightness) / max);
	pwm_config(pb->pwm, brightness, pb->period);		pwm_config(pb->pwm, brightness, pb->period);
	@@ -83,17 +90,98 @@ static const struct backlight_ops pwm_backlight_ops = {
	.check_fb = pwm_backlight_check_fb,		.check_fb = pwm_backlight_check_fb,
	};		};

			#ifdef CONFIG_OF
			static int pwm_backlight_parse_dt(struct device *dev,
			struct platform_pwm_backlight_data *data)
			{
			struct device_node *node = dev->of_node;
			struct property *prop;
			int length;
			u32 value;
			int ret;

			if (!node)
			return -ENODEV;

			memset(data, 0, sizeof(*data));

			/* determine the number of brightness levels */
			prop = of_find_property(node, "brightness-levels", &length);
			if (!prop)
			return -EINVAL;

			data->max_brightness = length / sizeof(u32);

			/* read brightness levels from DT property */
			if (data->max_brightness > 0) {
			size_t size = sizeof(data->levels) data->max_brightness;

			data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
			if (!data->levels)
			return -ENOMEM;

			ret = of_property_read_u32_array(node, "brightness-levels",
			data->levels,
			data->max_brightness);
			if (ret < 0)
			return ret;

			ret = of_property_read_u32(node, "default-brightness-level",
			&value);
			if (ret < 0)
			return ret;

			if (value >= data->max_brightness) {
			dev_warn(dev, "invalid default brightness level: %u, using %u\n",
			value, data->max_brightness - 1);
			value = data->max_brightness - 1;
			}

			data->dft_brightness = value;
			data->max_brightness--;
			}

			/*
			* TODO: Most users of this driver use a number of GPIOs to control
			* backlight power. Support for specifying these needs to be
			* added.
			*/

			return 0;
			}

			static struct of_device_id pwm_backlight_of_match[] = {
			{ .compatible = "pwm-backlight" },
			{ }
			};

			MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
			#else
			static int pwm_backlight_parse_dt(struct device *dev,
			struct platform_pwm_backlight_data *data)
			{
			return -ENODEV;
			}
			#endif

	static int pwm_backlight_probe(struct platform_device *pdev)		static int pwm_backlight_probe(struct platform_device *pdev)
	{		{
	struct backlight_properties props;
	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;		struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
			struct platform_pwm_backlight_data defdata;
			struct backlight_properties props;
	struct backlight_device *bl;		struct backlight_device *bl;
	struct pwm_bl_data *pb;		struct pwm_bl_data *pb;
			unsigned int max;
	int ret;		int ret;

	if (!data) {		if (!data) {
			ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
			if (ret < 0) {
	dev_err(&pdev->dev, "failed to find platform data\n");		dev_err(&pdev->dev, "failed to find platform data\n");
	return -EINVAL;		return ret;
			}

			data = &defdata;
	}		}

	if (data->init) {		if (data->init) {
	@@ -109,22 +197,43 @@ static int pwm_backlight_probe(struct platform_device *pdev)
	goto err_alloc;		goto err_alloc;
	}		}

	pb->period = data->pwm_period_ns;		if (data->levels) {
			max = data->levels[data->max_brightness];
			pb->levels = data->levels;
			} else
			max = data->max_brightness;

	pb->notify = data->notify;		pb->notify = data->notify;
	pb->notify_after = data->notify_after;		pb->notify_after = data->notify_after;
	pb->check_fb = data->check_fb;		pb->check_fb = data->check_fb;
	pb->lth_brightness = data->lth_brightness *		pb->exit = data->exit;
	(data->pwm_period_ns / data->max_brightness);
	pb->dev = &pdev->dev;		pb->dev = &pdev->dev;

	pb->pwm = pwm_request(data->pwm_id, "backlight");		pb->pwm = pwm_get(&pdev->dev, NULL);
	if (IS_ERR(pb->pwm)) {		if (IS_ERR(pb->pwm)) {
	dev_err(&pdev->dev, "unable to request PWM for backlight\n");		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");

			pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
			if (IS_ERR(pb->pwm)) {
			dev_err(&pdev->dev, "unable to request legacy PWM\n");
	ret = PTR_ERR(pb->pwm);		ret = PTR_ERR(pb->pwm);
	goto err_alloc;		goto err_alloc;
	} else		}
			}

	dev_dbg(&pdev->dev, "got pwm for backlight\n");		dev_dbg(&pdev->dev, "got pwm for backlight\n");

			/*
			* The DT case will set the pwm_period_ns field to 0 and store the
			* period, parsed from the DT, in the PWM device. For the non-DT case,
			* set the period from platform data.
			*/
			if (data->pwm_period_ns > 0)
			pwm_set_period(pb->pwm, data->pwm_period_ns);

			pb->period = pwm_get_period(pb->pwm);
			pb->lth_brightness = data->lth_brightness * (pb->period / max);

	memset(&props, 0, sizeof(struct backlight_properties));		memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_RAW;		props.type = BACKLIGHT_RAW;
	props.max_brightness = data->max_brightness;		props.max_brightness = data->max_brightness;
	@@ -143,7 +252,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
	return 0;		return 0;

	err_bl:		err_bl:
	pwm_free(pb->pwm);		pwm_put(pb->pwm);
	err_alloc:		err_alloc:
	if (data->exit)		if (data->exit)
	data->exit(&pdev->dev);		data->exit(&pdev->dev);
	@@ -152,16 +261,15 @@ static int pwm_backlight_probe(struct platform_device *pdev)

	static int pwm_backlight_remove(struct platform_device *pdev)		static int pwm_backlight_remove(struct platform_device *pdev)
	{		{
	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
	struct backlight_device *bl = platform_get_drvdata(pdev);		struct backlight_device *bl = platform_get_drvdata(pdev);
	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);		struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);

	backlight_device_unregister(bl);		backlight_device_unregister(bl);
	pwm_config(pb->pwm, 0, pb->period);		pwm_config(pb->pwm, 0, pb->period);
	pwm_disable(pb->pwm);		pwm_disable(pb->pwm);
	pwm_free(pb->pwm);		pwm_put(pb->pwm);
	if (data->exit)		if (pb->exit)
	data->exit(&pdev->dev);		pb->exit(&pdev->dev);
	return 0;		return 0;
	}		}

	@@ -200,6 +308,7 @@ static struct platform_driver pwm_backlight_driver = {
	#ifdef CONFIG_PM		#ifdef CONFIG_PM
	.pm = &pwm_backlight_pm_ops,		.pm = &pwm_backlight_pm_ops,
	#endif		#endif
			.of_match_table = of_match_ptr(pwm_backlight_of_match),
	},		},
	.probe = pwm_backlight_probe,		.probe = pwm_backlight_probe,
	.remove = pwm_backlight_remove,		.remove = pwm_backlight_remove,

include/linux/pwm_backlight.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -12,6 +12,7 @@ struct platform_pwm_backlight_data {
	unsigned int dft_brightness;		unsigned int dft_brightness;
	unsigned int lth_brightness;		unsigned int lth_brightness;
	unsigned int pwm_period_ns;		unsigned int pwm_period_ns;
			unsigned int *levels;
	int (init)(struct device dev);		int (init)(struct device dev);
	int (notify)(struct device dev, int brightness);		int (notify)(struct device dev, int brightness);
	void (notify_after)(struct device dev, int brightness);		void (notify_after)(struct device dev, int brightness);