Enable pinctrl for pwm-backlight.
Signed-off-by: Pantelis Antoniou <[email protected]>
---
drivers/video/backlight/pwm_bl.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 0c91023..f3b6194 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -20,6 +20,8 @@
#include <linux/pwm.h>
#include <linux/pwm_backlight.h>
#include <linux/slab.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/err.h>
struct pwm_bl_data {
struct pwm_device *pwm;
@@ -180,9 +182,14 @@ static int pwm_backlight_probe(struct platform_device *pdev)
struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
+ struct pinctrl *pinctrl;
unsigned int max;
int ret;
+ pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
+ if (IS_ERR(pinctrl))
+ dev_warn(&pdev->dev, "unable to select pin group\n");
+
if (!data) {
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
if (ret < 0) {
--
1.7.12
On Wed, Oct 31, 2012 at 05:57:27PM +0200, Pantelis Antoniou wrote:
[...]
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
[...]
> @@ -20,6 +20,8 @@
> #include <linux/pwm.h>
> #include <linux/pwm_backlight.h>
> #include <linux/slab.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/err.h>
linux/err.h is already included earlier.
Thierry
On Wed, Oct 31, 2012 at 05:57:27PM +0200, Pantelis Antoniou wrote:
> Enable pinctrl for pwm-backlight.
>
> Signed-off-by: Pantelis Antoniou <[email protected]>
> ---
> drivers/video/backlight/pwm_bl.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 0c91023..f3b6194 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -20,6 +20,8 @@
> #include <linux/pwm.h>
> #include <linux/pwm_backlight.h>
> #include <linux/slab.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/err.h>
>
> struct pwm_bl_data {
> struct pwm_device *pwm;
> @@ -180,9 +182,14 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> struct backlight_properties props;
> struct backlight_device *bl;
> struct pwm_bl_data *pb;
> + struct pinctrl *pinctrl;
> unsigned int max;
> int ret;
>
> + pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
> + if (IS_ERR(pinctrl))
> + dev_warn(&pdev->dev, "unable to select pin group\n");
> +
I just saw this done in a similar way in some other driver and then
remembered your patch. When I reviewed this I wasn't sure if a warning
was good enough in this case. I've checked the kernel tree and it seems
like a majority handled this as failure instead of a warning. I took a
look at the pinctrl core and it seems like indeed if neither pinctrl is
enabled or if there isn't actually a pinmux configuration for a device,
then devm_pinctrl_get_select_default() will actually not return an
error, so in those cases where an error is returned it should actually
be handled as a fatal error.
I'm Cc'ing Linus Walleij, maybe he knows what to do.
Thierry
> if (!data) {
> ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
> if (ret < 0) {
> --
> 1.7.12
>
>
>
On Fri, Nov 9, 2012 at 9:06 AM, Thierry Reding
<[email protected]> wrote:
> On Wed, Oct 31, 2012 at 05:57:27PM +0200, Pantelis Antoniou wrote:
>> + pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
>> + if (IS_ERR(pinctrl))
>> + dev_warn(&pdev->dev, "unable to select pin group\n");
>> +
>
> I just saw this done in a similar way in some other driver and then
> remembered your patch. When I reviewed this I wasn't sure if a warning
> was good enough in this case. I've checked the kernel tree and it seems
> like a majority handled this as failure instead of a warning. I took a
> look at the pinctrl core and it seems like indeed if neither pinctrl is
> enabled or if there isn't actually a pinmux configuration for a device,
> then devm_pinctrl_get_select_default() will actually not return an
> error, so in those cases where an error is returned it should actually
> be handled as a fatal error.
So it depends.
One good reason to just error out and return the error code is
if the error returned is -EPROBE_DEFER, right?
Because then you're pinctrl driver is not up yet, and you
need to bail out and be revisited later.
On a related key we have this debate going on with some
subsystem maintainers as to whether we should try do
centralize boilerplate like this, the lates suggestion is:
http://marc.info/?l=linux-kernel&m=135263661110528&w=2
The fun never ends...
Yours,
Linus Walleij
Hi Linus,
On Nov 11, 2012, at 7:26 PM, Linus Walleij wrote:
> On Fri, Nov 9, 2012 at 9:06 AM, Thierry Reding
> <[email protected]> wrote:
>> On Wed, Oct 31, 2012 at 05:57:27PM +0200, Pantelis Antoniou wrote:
>
>>> + pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
>>> + if (IS_ERR(pinctrl))
>>> + dev_warn(&pdev->dev, "unable to select pin group\n");
>>> +
>>
>> I just saw this done in a similar way in some other driver and then
>> remembered your patch. When I reviewed this I wasn't sure if a warning
>> was good enough in this case. I've checked the kernel tree and it seems
>> like a majority handled this as failure instead of a warning. I took a
>> look at the pinctrl core and it seems like indeed if neither pinctrl is
>> enabled or if there isn't actually a pinmux configuration for a device,
>> then devm_pinctrl_get_select_default() will actually not return an
>> error, so in those cases where an error is returned it should actually
>> be handled as a fatal error.
>
> So it depends.
>
> One good reason to just error out and return the error code is
> if the error returned is -EPROBE_DEFER, right?
>
> Because then you're pinctrl driver is not up yet, and you
> need to bail out and be revisited later.
>
> On a related key we have this debate going on with some
> subsystem maintainers as to whether we should try do
> centralize boilerplate like this, the lates suggestion is:
> http://marc.info/?l=linux-kernel&m=135263661110528&w=2
>
Interesting... This is certainly much nicer than peppering all the
devices with pinctrl calls.
> The fun never ends...
>
Indeed.
> Yours,
> Linus Walleij
Regards
-- Pantelis