* [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT
@ 2014-08-20 6:38 Lothar Waßmann
2014-08-20 7:32 ` Thierry Reding
2014-08-20 12:17 ` Lee Jones
0 siblings, 2 replies; 3+ messages in thread
From: Lothar Waßmann @ 2014-08-20 6:38 UTC (permalink / raw)
To: Bryan Wu, Jean-Christophe Plagniol-Villard, Jingoo Han,
Lee Jones, Thierry Reding, Tomi Valkeinen, linux-fbdev,
linux-kernel, linux-pwm
Cc: Lothar Waßmann
commit 257462dbf3ed ("pwm-backlight: switch to gpiod interface")
introduced a regression leading to acquiring a bogus GPIO-0 when
configured from DT without an 'enable-gpios' property.
The driver will happily accept the 0 initialized 'enable_gpio' member
of the struct platform_pwm_backlight_data as valid gpio number, and
request this GPIO as enable pin. In case of multiple driver instances,
the second will fail to register with the error message:
pwm-backlight backlight1.23: failed to request GPIO#0: -16
Fix this by setting enable_gpio in the pdata struct to -EINVAL.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
---
drivers/video/backlight/pwm_bl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index d7a3d13..e6ef6b4 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -172,7 +172,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
data->dft_brightness = value;
data->max_brightness--;
}
-
+ data->enable_gpio = -EINVAL;
return 0;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT
2014-08-20 6:38 [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT Lothar Waßmann
@ 2014-08-20 7:32 ` Thierry Reding
2014-08-20 12:17 ` Lee Jones
1 sibling, 0 replies; 3+ messages in thread
From: Thierry Reding @ 2014-08-20 7:32 UTC (permalink / raw)
To: Lothar Waßmann
Cc: Bryan Wu, Jean-Christophe Plagniol-Villard, Jingoo Han,
Lee Jones, Tomi Valkeinen, linux-fbdev, linux-kernel, linux-pwm
[-- Attachment #1: Type: text/plain, Size: 1352 bytes --]
On Wed, Aug 20, 2014 at 08:38:36AM +0200, Lothar Waßmann wrote:
> commit 257462dbf3ed ("pwm-backlight: switch to gpiod interface")
> introduced a regression leading to acquiring a bogus GPIO-0 when
> configured from DT without an 'enable-gpios' property.
> The driver will happily accept the 0 initialized 'enable_gpio' member
> of the struct platform_pwm_backlight_data as valid gpio number, and
> request this GPIO as enable pin. In case of multiple driver instances,
> the second will fail to register with the error message:
> pwm-backlight backlight1.23: failed to request GPIO#0: -16
>
> Fix this by setting enable_gpio in the pdata struct to -EINVAL.
>
> Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
> ---
> drivers/video/backlight/pwm_bl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index d7a3d13..e6ef6b4 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -172,7 +172,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
> data->dft_brightness = value;
> data->max_brightness--;
> }
> -
> + data->enable_gpio = -EINVAL;
I'd prefer to keep the blank line for readability. Other than that:
Acked-by: Thierry Reding <treding@nvidia.com>
[-- Attachment #2: Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT
2014-08-20 6:38 [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT Lothar Waßmann
2014-08-20 7:32 ` Thierry Reding
@ 2014-08-20 12:17 ` Lee Jones
1 sibling, 0 replies; 3+ messages in thread
From: Lee Jones @ 2014-08-20 12:17 UTC (permalink / raw)
To: Lothar Waßmann
Cc: Bryan Wu, Jean-Christophe Plagniol-Villard, Jingoo Han,
Thierry Reding, Tomi Valkeinen, linux-fbdev, linux-kernel,
linux-pwm
On Wed, 20 Aug 2014, Lothar Waßmann wrote:
> commit 257462dbf3ed ("pwm-backlight: switch to gpiod interface")
> introduced a regression leading to acquiring a bogus GPIO-0 when
> configured from DT without an 'enable-gpios' property.
> The driver will happily accept the 0 initialized 'enable_gpio' member
> of the struct platform_pwm_backlight_data as valid gpio number, and
> request this GPIO as enable pin. In case of multiple driver instances,
> the second will fail to register with the error message:
> pwm-backlight backlight1.23: failed to request GPIO#0: -16
>
> Fix this by setting enable_gpio in the pdata struct to -EINVAL.
>
> Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
> ---
> drivers/video/backlight/pwm_bl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied to -fixes with Thierry's Ack and the blank line left.
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index d7a3d13..e6ef6b4 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -172,7 +172,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
> data->dft_brightness = value;
> data->max_brightness--;
> }
> -
> + data->enable_gpio = -EINVAL;
> return 0;
> }
>
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-08-20 6:38 [PATCH] pwm-backlight: fix bogus request for GPIO#0 when instantiated from DT Lothar Waßmann
2014-08-20 7:32 ` Thierry Reding
2014-08-20 12:17 ` Lee Jones
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