diff mbox

mfd: max8925: fix dt code for backlight

Message ID 1374680547-5336-1-git-send-email-olof@lixom.net (mailing list archive)
State New, archived
Headers show

Commit Message

Olof Johansson July 24, 2013, 3:42 p.m. UTC
The device-tree enablement for max8925 has several problems, but besides
the bindings being wrong (and not having seen review) there's also some
bad coding practices on how to fill in the platform_data from device tree.

I came across this since it causes a warning when compiling
mmp2_defconfig, and instead of doing the minimal fix to silence the
warning, I restructured the code a bit.

This silences the warning:
drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe':
drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value]

Note that the bindings themselves need to be revisited too, but that will
affect more than just the backlight driver and is best done separately;
this just fixes the bad code for the backlight driver.

Signed-off-by: Olof Johansson <olof@lixom.net>
---

Richard, Jingoo, this would be good to see go into 3.11 if you're
comfortable with it.


-Olof

 drivers/video/backlight/max8925_bl.c |   41 +++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 20 deletions(-)

Comments

Jingoo Han July 25, 2013, 1:13 a.m. UTC | #1
On Thursday, July 25, 2013 12:42 AM, Olof Johansson wrote:
> 
> The device-tree enablement for max8925 has several problems, but besides
> the bindings being wrong (and not having seen review) there's also some
> bad coding practices on how to fill in the platform_data from device tree.
> 
> I came across this since it causes a warning when compiling
> mmp2_defconfig, and instead of doing the minimal fix to silence the
> warning, I restructured the code a bit.
> 
> This silences the warning:
> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe':
> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value]
> 
> Note that the bindings themselves need to be revisited too, but that will
> affect more than just the backlight driver and is best done separately;
> this just fixes the bad code for the backlight driver.
> 
> Signed-off-by: Olof Johansson <olof@lixom.net>
> ---
> 
> Richard, Jingoo, this would be good to see go into 3.11 if you're
> comfortable with it.

CC'ed Andrew Morton


Hi Olof Johansson,

Currently, there is not git tree for Backlight subsystem.
I hope that this would go into 3.11 through one of other trees
with my Ack.

If not, it will go into 3.12-rc1 through mm-tree.

Acked-by: Jingoo Han <jg1.han@samsung.com>


Best regards,
Jingoo Han

> 
> 
> -Olof
> 
>  drivers/video/backlight/max8925_bl.c |   41 +++++++++++++++++-----------------
>  1 file changed, 21 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c
> index 5ca11b0..886e797 100644
> --- a/drivers/video/backlight/max8925_bl.c
> +++ b/drivers/video/backlight/max8925_bl.c
> @@ -101,33 +101,37 @@ static const struct backlight_ops max8925_backlight_ops = {
>  	.get_brightness	= max8925_backlight_get_brightness,
>  };
> 
> -#ifdef CONFIG_OF
> -static int max8925_backlight_dt_init(struct platform_device *pdev,
> -			      struct max8925_backlight_pdata *pdata)
> +static void max8925_backlight_dt_init(struct platform_device *pdev)
>  {
>  	struct device_node *nproot = pdev->dev.parent->of_node, *np;
> -	int dual_string;
> +	struct max8925_backlight_pdata *pdata;
> +	u32 val;
> +
> +	if (!nproot || !IS_ENABLED(CONFIG_OF))
> +		return;
> +
> +	pdata = devm_kzalloc(&pdev->dev,
> +			     sizeof(struct max8925_backlight_pdata),
> +			     GFP_KERNEL);
> +	if (!pdata)
> +		return;
> 
> -	if (!nproot)
> -		return -ENODEV;
>  	np = of_find_node_by_name(nproot, "backlight");
>  	if (!np) {
>  		dev_err(&pdev->dev, "failed to find backlight node\n");
> -		return -ENODEV;
> +		return;
>  	}
> 
> -	of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string);
> -	pdata->dual_string = dual_string;
> -	return 0;
> +	if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
> +		pdata->dual_string = val;
> +
> +	pdev->dev.platform_data = pdata;
>  }
> -#else
> -#define max8925_backlight_dt_init(x, y)	(-1)
> -#endif
> 
>  static int max8925_backlight_probe(struct platform_device *pdev)
>  {
>  	struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
> -	struct max8925_backlight_pdata *pdata = pdev->dev.platform_data;
> +	struct max8925_backlight_pdata *pdata;
>  	struct max8925_backlight_data *data;
>  	struct backlight_device *bl;
>  	struct backlight_properties props;
> @@ -170,13 +174,10 @@ static int max8925_backlight_probe(struct platform_device *pdev)
>  	platform_set_drvdata(pdev, bl);
> 
>  	value = 0;
> -	if (pdev->dev.parent->of_node && !pdata) {
> -		pdata = devm_kzalloc(&pdev->dev,
> -				     sizeof(struct max8925_backlight_pdata),
> -				     GFP_KERNEL);
> -		max8925_backlight_dt_init(pdev, pdata);
> -	}
> +	if (!pdev->dev.platform_data)
> +		max8925_backlight_dt_init(pdev);
> 
> +	pdata = pdev->dev.platform_data;
>  	if (pdata) {
>  		if (pdata->lxw_scl)
>  			value |= (1 << 7);
> --
> 1.7.10.4
Olof Johansson July 25, 2013, 9 p.m. UTC | #2
On Wed, Jul 24, 2013 at 6:13 PM, Jingoo Han <jg1.han@samsung.com> wrote:
> On Thursday, July 25, 2013 12:42 AM, Olof Johansson wrote:
>>
>> The device-tree enablement for max8925 has several problems, but besides
>> the bindings being wrong (and not having seen review) there's also some
>> bad coding practices on how to fill in the platform_data from device tree.
>>
>> I came across this since it causes a warning when compiling
>> mmp2_defconfig, and instead of doing the minimal fix to silence the
>> warning, I restructured the code a bit.
>>
>> This silences the warning:
>> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe':
>> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value]
>>
>> Note that the bindings themselves need to be revisited too, but that will
>> affect more than just the backlight driver and is best done separately;
>> this just fixes the bad code for the backlight driver.
>>
>> Signed-off-by: Olof Johansson <olof@lixom.net>
>> ---
>>
>> Richard, Jingoo, this would be good to see go into 3.11 if you're
>> comfortable with it.
>
> CC'ed Andrew Morton
>
>
> Hi Olof Johansson,
>
> Currently, there is not git tree for Backlight subsystem.
> I hope that this would go into 3.11 through one of other trees
> with my Ack.
>
> If not, it will go into 3.12-rc1 through mm-tree.
>
> Acked-by: Jingoo Han <jg1.han@samsung.com>

Ok, if you don't mind I can take it through arm-soc for 3.11 with your ack then.

Thanks!

-Olof
Jingoo Han July 25, 2013, 11:17 p.m. UTC | #3
On Friday, July 26, 2013 6:01 AM, Olof Johansson wrote:
> On Wed, Jul 24, 2013 at 6:13 PM, Jingoo Han <jg1.han@samsung.com> wrote:
> > On Thursday, July 25, 2013 12:42 AM, Olof Johansson wrote:
> >>
> >> The device-tree enablement for max8925 has several problems, but besides
> >> the bindings being wrong (and not having seen review) there's also some
> >> bad coding practices on how to fill in the platform_data from device tree.
> >>
> >> I came across this since it causes a warning when compiling
> >> mmp2_defconfig, and instead of doing the minimal fix to silence the
> >> warning, I restructured the code a bit.
> >>
> >> This silences the warning:
> >> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe':
> >> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value]
> >>
> >> Note that the bindings themselves need to be revisited too, but that will
> >> affect more than just the backlight driver and is best done separately;
> >> this just fixes the bad code for the backlight driver.
> >>
> >> Signed-off-by: Olof Johansson <olof@lixom.net>
> >> ---
> >>
> >> Richard, Jingoo, this would be good to see go into 3.11 if you're
> >> comfortable with it.
> >
> > CC'ed Andrew Morton
> >
> >
> > Hi Olof Johansson,
> >
> > Currently, there is not git tree for Backlight subsystem.
> > I hope that this would go into 3.11 through one of other trees
> > with my Ack.
> >
> > If not, it will go into 3.12-rc1 through mm-tree.
> >
> > Acked-by: Jingoo Han <jg1.han@samsung.com>
> 
> Ok, if you don't mind I can take it through arm-soc for 3.11 with your ack then. 

Hi Olof Johansson,

Sure, no problem.
If you take it through arm-soc for 3.11 with my ACK, it will be good.
Thank you for caring this. :)

Best regards,
Jingoo Han
diff mbox

Patch

diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c
index 5ca11b0..886e797 100644
--- a/drivers/video/backlight/max8925_bl.c
+++ b/drivers/video/backlight/max8925_bl.c
@@ -101,33 +101,37 @@  static const struct backlight_ops max8925_backlight_ops = {
 	.get_brightness	= max8925_backlight_get_brightness,
 };
 
-#ifdef CONFIG_OF
-static int max8925_backlight_dt_init(struct platform_device *pdev,
-			      struct max8925_backlight_pdata *pdata)
+static void max8925_backlight_dt_init(struct platform_device *pdev)
 {
 	struct device_node *nproot = pdev->dev.parent->of_node, *np;
-	int dual_string;
+	struct max8925_backlight_pdata *pdata;
+	u32 val;
+
+	if (!nproot || !IS_ENABLED(CONFIG_OF))
+		return;
+
+	pdata = devm_kzalloc(&pdev->dev,
+			     sizeof(struct max8925_backlight_pdata),
+			     GFP_KERNEL);
+	if (!pdata)
+		return;
 
-	if (!nproot)
-		return -ENODEV;
 	np = of_find_node_by_name(nproot, "backlight");
 	if (!np) {
 		dev_err(&pdev->dev, "failed to find backlight node\n");
-		return -ENODEV;
+		return;
 	}
 
-	of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string);
-	pdata->dual_string = dual_string;
-	return 0;
+	if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
+		pdata->dual_string = val;
+
+	pdev->dev.platform_data = pdata;
 }
-#else
-#define max8925_backlight_dt_init(x, y)	(-1)
-#endif
 
 static int max8925_backlight_probe(struct platform_device *pdev)
 {
 	struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
-	struct max8925_backlight_pdata *pdata = pdev->dev.platform_data;
+	struct max8925_backlight_pdata *pdata;
 	struct max8925_backlight_data *data;
 	struct backlight_device *bl;
 	struct backlight_properties props;
@@ -170,13 +174,10 @@  static int max8925_backlight_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, bl);
 
 	value = 0;
-	if (pdev->dev.parent->of_node && !pdata) {
-		pdata = devm_kzalloc(&pdev->dev,
-				     sizeof(struct max8925_backlight_pdata),
-				     GFP_KERNEL);
-		max8925_backlight_dt_init(pdev, pdata);
-	}
+	if (!pdev->dev.platform_data)
+		max8925_backlight_dt_init(pdev);
 
+	pdata = pdev->dev.platform_data;
 	if (pdata) {
 		if (pdata->lxw_scl)
 			value |= (1 << 7);