backlight: pwm_bl: Fix brightness levels for non-DT case. (d347d0c8) · Commits · 戴 / test

Commit ' ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")' allows the possibility to compute a default brightness table when there isn't the brightness-levels property in the DT. Unfortunately the changes made broke the pwm backlight for the non-DT boards. Usually, the non-DT boards don't pass the brightness levels via platform data, instead, it sets the max_brightness in their platform data and the driver calculates the level without a table. The offending patch assumed that when there is no brightness levels table we should create one, but this is clearly wrong for the non-DT case. After this patch the code handles the DT and the non-DT case taking in consideration also if max_brightness is set or not. Fixes: ("backlight: pwm_bl: Compute brightness of LED linearly to human eye") Reported-by:

Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by:

Enric Balletbo i Serra <enric.balletbo@collabora.com> Tested-by:

Robert Jarzmik <robert.jarzmik@free.fr> Acked-by:

Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by:

Lee Jones <lee.jones@linaro.org>

drivers/video/backlight/pwm_bl.c

+35 −6

Original line number	Diff line number	Diff line
		@@ -562,7 +562,30 @@ static int pwm_backlight_probe(struct platform_device *pdev)
		goto err_alloc;
		}

		if (!data->levels) {
		if (data->levels) {
		/*
		* For the DT case, only when brightness levels is defined
		* data->levels is filled. For the non-DT case, data->levels
		* can come from platform data, however is not usual.
		*/
		for (i = 0; i <= data->max_brightness; i++) {
		if (data->levels[i] > pb->scale)
		pb->scale = data->levels[i];

		pb->levels = data->levels;
		}
		} else if (!data->max_brightness) {
		/*
		* If no brightness levels are provided and max_brightness is
		* not set, use the default brightness table. For the DT case,
		* max_brightness is set to 0 when brightness levels is not
		* specified. For the non-DT case, max_brightness is usually
		* set to some value.
		*/

		/* Get the PWM period (in nanoseconds) */
		pwm_get_state(pb->pwm, &state);

		ret = pwm_backlight_brightness_default(&pdev->dev, data,
		state.period);
		if (ret < 0) {
		@@ -570,7 +593,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
		"failed to setup default brightness table\n");
		goto err_alloc;
		}
		}

		for (i = 0; i <= data->max_brightness; i++) {
		if (data->levels[i] > pb->scale)
		@@ -578,6 +600,13 @@ static int pwm_backlight_probe(struct platform_device *pdev)

		pb->levels = data->levels;
		}
		} else {
		/*
		* That only happens for the non-DT case, where platform data
		* sets the max_brightness value.
		*/
		pb->scale = data->max_brightness;
		}

		pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);

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