On Wed, Oct 23, 2013 at 10:20:59AM +0900, Jingoo Han wrote:

On Wednesday, October 23, 2013 2:27 AM, Johan Hovold wrote:

quoted

The driver supports 16-bit brightness values, but the value returned
from get_brightness was truncated to eight bits.

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <redacted>
---
 drivers/video/backlight/atmel-pwm-bl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/video/backlight/atmel-pwm-bl.c b/drivers/video/backlight/atmel-pwm-bl.c
index 66885fb..8aac273 100644
--- a/drivers/video/backlight/atmel-pwm-bl.c
+++ b/drivers/video/backlight/atmel-pwm-bl.c

@@ -70,7 +70,7 @@ static int atmel_pwm_bl_set_intensity(struct backlight_device *bd)
 static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
 {
 	struct atmel_pwm_bl *pwmbl = bl_get_data(bd);
-	u8 intensity;
+	u32 intensity;

 	if (pwmbl->pdata->pwm_active_low) {
 		intensity = pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY) -

@@ -80,7 +80,7 @@ static int atmel_pwm_bl_get_intensity(struct backlight_device *bd)
 			pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
 	}

-	return intensity;
+	return (u16)intensity;

However, atmel_pwm_bl_get_intensity() should return 'int',
instead of 'u16'.

Yes, but the cast to int is implicit. Perhaps

	return (intensity & 0xffff);

(or just a comment) would make it more clear why the cast is there.

Also, pwm_channel_readl() returns 'u32'.

Yes, (and only the 16 least-significant bits are used). That and the
fact that the platform-data limits are currently unsigned long (I was
considering fixing this later) was why I preferred keeping all register
value manipulation in u32 and do a single cast at the end.

This would actually introduce a new conversion warning (unless you add
parentheses as well) as pwm_duty_min is unsigned long. Same below.

	} else {
-		intensity = pwmbl->pdata->pwm_duty_max -
+		intensity = (u16) pwmbl->pdata->pwm_duty_max -
			pwm_channel_readl(&pwmbl->pwmc, PWM_CDTY);
	}

-	return intensity;
+	return (int)intensity;
 }

However, if you feel strongly about this, I'll respin the series (a later
patch would likely no longer apply), use u16 and add casts to the two
assignments.

Thanks,
Johan