diff mbox

[4/4] media: mx2_camera: Fix clock handling for i.MX27.

Message ID 1343301637-19676-5-git-send-email-javier.martin@vista-silicon.com (mailing list archive)
State New, archived
Headers show

Commit Message

Javier Martin July 26, 2012, 11:20 a.m. UTC
This driver wasn't converted to the new clock framework
(e038ed50a4a767add205094c035b6943e7b30140).

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
---
 drivers/media/video/mx2_camera.c |   67 ++++++++++++++++++++++----------------
 1 file changed, 39 insertions(+), 28 deletions(-)

Comments

Guennadi Liakhovetski July 31, 2012, 3:14 p.m. UTC | #1
Hi Javier

Thanks for the patch. Let me try to understand what it is doing, please, 
correct any my mistakes.

On Thu, 26 Jul 2012, Javier Martin wrote:

> This driver wasn't converted to the new clock framework
> (e038ed50a4a767add205094c035b6943e7b30140).
> 
> Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
> ---
>  drivers/media/video/mx2_camera.c |   67 ++++++++++++++++++++++----------------
>  1 file changed, 39 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/media/video/mx2_camera.c b/drivers/media/video/mx2_camera.c
> index 3c38b5f..88dcae6 100644
> --- a/drivers/media/video/mx2_camera.c
> +++ b/drivers/media/video/mx2_camera.c
> @@ -273,7 +273,7 @@ struct mx2_camera_dev {
>  	struct device		*dev;
>  	struct soc_camera_host	soc_host;
>  	struct soc_camera_device *icd;
> -	struct clk		*clk_csi, *clk_emma;
> +	struct clk		*clk_csi, *clk_emma_ahb, *clk_emma_ipg;
>  
>  	unsigned int		irq_csi, irq_emma;
>  	void __iomem		*base_csi, *base_emma;
> @@ -436,7 +436,8 @@ static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
>  {
>  	unsigned long flags;
>  
> -	clk_disable(pcdev->clk_csi);
> +	if (cpu_is_mx27())
> +		clk_disable_unprepare(pcdev->clk_csi);

This tells me, there are already 2 things going on here:

1. add clock-(un)prepare operations to enable / disable. Is this a problem 
atm? is the driver non-functional without this change or is it just an API 
correctness change? I thought you replied to this already, but 
unfortunately I couldn't find that your reply again, sorry.

2. use clocks only on i.MX27

>  	writel(0, pcdev->base_csi + CSICR1);
>  	if (cpu_is_mx27()) {
>  		writel(0, pcdev->base_emma + PRP_CNTL);
> @@ -464,9 +465,11 @@ static int mx2_camera_add_device(struct soc_camera_device *icd)
>  	if (pcdev->icd)
>  		return -EBUSY;
>  
> -	ret = clk_enable(pcdev->clk_csi);
> -	if (ret < 0)
> -		return ret;
> +	if (cpu_is_mx27()) {
> +		ret = clk_prepare_enable(pcdev->clk_csi);
> +		if (ret < 0)
> +			return ret;
> +	}

Same two as above.

>  
>  	csicr1 = CSICR1_MCLKEN;
>  
> @@ -1675,23 +1678,12 @@ static int __devinit mx27_camera_emma_init(struct mx2_camera_dev *pcdev)
>  		goto exit_iounmap;
>  	}
>  
> -	pcdev->clk_emma = clk_get(NULL, "emma");
> -	if (IS_ERR(pcdev->clk_emma)) {
> -		err = PTR_ERR(pcdev->clk_emma);
> -		goto exit_free_irq;
> -	}
> -
> -	clk_enable(pcdev->clk_emma);
> -
>  	err = mx27_camera_emma_prp_reset(pcdev);
>  	if (err)
> -		goto exit_clk_emma_put;
> +		goto exit_free_irq;
>  
>  	return err;
>  
> -exit_clk_emma_put:
> -	clk_disable(pcdev->clk_emma);
> -	clk_put(pcdev->clk_emma);
>  exit_free_irq:
>  	free_irq(pcdev->irq_emma, pcdev);
>  exit_iounmap:
> @@ -1714,6 +1706,7 @@ static int __devinit mx2_camera_probe(struct platform_device *pdev)
>  
>  	res_csi = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	irq_csi = platform_get_irq(pdev, 0);
> +
>  	if (res_csi == NULL || irq_csi < 0) {
>  		dev_err(&pdev->dev, "Missing platform resources data\n");
>  		err = -ENODEV;
> @@ -1727,11 +1720,26 @@ static int __devinit mx2_camera_probe(struct platform_device *pdev)
>  		goto exit;
>  	}
>  
> -	pcdev->clk_csi = clk_get(&pdev->dev, NULL);
> -	if (IS_ERR(pcdev->clk_csi)) {
> -		dev_err(&pdev->dev, "Could not get csi clock\n");
> -		err = PTR_ERR(pcdev->clk_csi);
> -		goto exit_kfree;
> +	if (cpu_is_mx27()) {
> +		pcdev->clk_csi = devm_clk_get(&pdev->dev, "ahb");
> +		if (IS_ERR(pcdev->clk_csi)) {
> +			dev_err(&pdev->dev, "Could not get csi clock\n");
> +			err = PTR_ERR(pcdev->clk_csi);
> +			goto exit_kfree;
> +		}
> +		pcdev->clk_emma_ipg = devm_clk_get(&pdev->dev, "emma-ipg");
> +		if (IS_ERR(pcdev->clk_emma_ipg)) {
> +			err = PTR_ERR(pcdev->clk_emma_ipg);
> +			goto exit_kfree;
> +		}
> +		pcdev->clk_emma_ahb = devm_clk_get(&pdev->dev, "emma-ahb");
> +		if (IS_ERR(pcdev->clk_emma_ahb)) {
> +			err = PTR_ERR(pcdev->clk_emma_ahb);
> +			goto exit_kfree;
> +		}
> +		clk_prepare_enable(pcdev->clk_csi);
> +		clk_prepare_enable(pcdev->clk_emma_ipg);
> +		clk_prepare_enable(pcdev->clk_emma_ahb);
>  	}
>  
>  	pcdev->res_csi = res_csi;

This does:

1. add clock-(un)prepare operations to enable / disable.

2. use clocks only on i.MX27

3. switch to managed clock requesting

4. groups clk_get(_devm)() and clk_prepare(_enable)() calls together

> @@ -1827,8 +1835,8 @@ exit_free_emma:
>  eallocctx:
>  	if (cpu_is_mx27()) {
>  		free_irq(pcdev->irq_emma, pcdev);
> -		clk_disable(pcdev->clk_emma);
> -		clk_put(pcdev->clk_emma);
> +		clk_disable_unprepare(pcdev->clk_emma_ipg);
> +		clk_disable_unprepare(pcdev->clk_emma_ahb);
>  		iounmap(pcdev->base_emma);
>  		release_mem_region(pcdev->res_emma->start, resource_size(pcdev->res_emma));
>  	}
> @@ -1840,7 +1848,11 @@ exit_iounmap:
>  exit_release:
>  	release_mem_region(res_csi->start, resource_size(res_csi));
>  exit_dma_free:
> -	clk_put(pcdev->clk_csi);
> +	if (cpu_is_mx27()) {
> +		clk_disable_unprepare(pcdev->clk_emma_ipg);
> +		clk_disable_unprepare(pcdev->clk_emma_ahb);
> +		clk_disable_unprepare(pcdev->clk_csi);
> +	}
>  exit_kfree:
>  	kfree(pcdev);
>  exit:
> @@ -1854,7 +1866,6 @@ static int __devexit mx2_camera_remove(struct platform_device *pdev)
>  			struct mx2_camera_dev, soc_host);
>  	struct resource *res;
>  
> -	clk_put(pcdev->clk_csi);
>  	if (cpu_is_mx25())
>  		free_irq(pcdev->irq_csi, pcdev);
>  	if (cpu_is_mx27())
> @@ -1867,8 +1878,8 @@ static int __devexit mx2_camera_remove(struct platform_device *pdev)
>  	iounmap(pcdev->base_csi);
>  
>  	if (cpu_is_mx27()) {
> -		clk_disable(pcdev->clk_emma);
> -		clk_put(pcdev->clk_emma);
> +		clk_disable_unprepare(pcdev->clk_emma_ipg);
> +		clk_disable_unprepare(pcdev->clk_emma_ahb);
>  		iounmap(pcdev->base_emma);
>  		res = pcdev->res_emma;
>  		release_mem_region(res->start, resource_size(res));
> -- 
> 1.7.9.5

The rest adds to the implementation of the above 4 points.

So, if this is correct, my suggestion would be:

1. Don't make the CSI clock i.MX27-specific. You can do

-	pcdev->clk_csi = clk_get(&pdev->dev, NULL);
+	pcdev->clk_csi = clk_get(&pdev->dev, "ahb");

If NULL connection ID worked for i.MX25 before, using any non-empty string 
will work too.

2. I would rather not re-group clock requesting. It is not too unlogical, 
that mx27_camera_emma_init() allocates EMMA clocks. And keeping the CSI 
clock where it is would anyway make your grouping look less symmetric than 
in this version.

3. identify the real bug-fix portion of this patch and separate it from 
all other changes. Is the fix in using two separate "emma-ipg" and 
"emma-ahb" clocks instead of just a single "emma?" Or is prepare / 
unprepare also required? Please, make these to 1 or two _fix_ patches and 
the rest you can put in a clean-up / feature / improvement patch.

Does this make sense?

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
Sascha Hauer July 31, 2012, 5:49 p.m. UTC | #2
Hi Guennadi,

On Tue, Jul 31, 2012 at 05:14:25PM +0200, Guennadi Liakhovetski wrote:
> Hi Javier
> 
> > @@ -436,7 +436,8 @@ static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
> >  {
> >  	unsigned long flags;
> >  
> > -	clk_disable(pcdev->clk_csi);
> > +	if (cpu_is_mx27())
> > +		clk_disable_unprepare(pcdev->clk_csi);
> 
> This tells me, there are already 2 things going on here:
> 
> 1. add clock-(un)prepare operations to enable / disable. Is this a problem 
> atm? is the driver non-functional without this change or is it just an API 
> correctness change? I thought you replied to this already, but 
> unfortunately I couldn't find that your reply again, sorry.

Since the common clock framework clk_prepare is mandatory.

Sascha
Guennadi Liakhovetski Aug. 1, 2012, 7:02 a.m. UTC | #3
Hi Sascha

On Tue, 31 Jul 2012, Sascha Hauer wrote:

> Hi Guennadi,
> 
> On Tue, Jul 31, 2012 at 05:14:25PM +0200, Guennadi Liakhovetski wrote:
> > Hi Javier
> > 
> > > @@ -436,7 +436,8 @@ static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
> > >  {
> > >  	unsigned long flags;
> > >  
> > > -	clk_disable(pcdev->clk_csi);
> > > +	if (cpu_is_mx27())
> > > +		clk_disable_unprepare(pcdev->clk_csi);
> > 
> > This tells me, there are already 2 things going on here:
> > 
> > 1. add clock-(un)prepare operations to enable / disable. Is this a problem 
> > atm? is the driver non-functional without this change or is it just an API 
> > correctness change? I thought you replied to this already, but 
> > unfortunately I couldn't find that your reply again, sorry.
> 
> Since the common clock framework clk_prepare is mandatory.

Good, thanks for the clarification. So, this is not a functional, but a 
correctness fix. I think, such fixes are acceptable after -rc1 until 
something like -rc5, but maybe not after that. So, I'd try to push this 
some time within the next couple of weeks, once I get this fix as a 
separate patch.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
diff mbox

Patch

diff --git a/drivers/media/video/mx2_camera.c b/drivers/media/video/mx2_camera.c
index 3c38b5f..88dcae6 100644
--- a/drivers/media/video/mx2_camera.c
+++ b/drivers/media/video/mx2_camera.c
@@ -273,7 +273,7 @@  struct mx2_camera_dev {
 	struct device		*dev;
 	struct soc_camera_host	soc_host;
 	struct soc_camera_device *icd;
-	struct clk		*clk_csi, *clk_emma;
+	struct clk		*clk_csi, *clk_emma_ahb, *clk_emma_ipg;
 
 	unsigned int		irq_csi, irq_emma;
 	void __iomem		*base_csi, *base_emma;
@@ -436,7 +436,8 @@  static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
 {
 	unsigned long flags;
 
-	clk_disable(pcdev->clk_csi);
+	if (cpu_is_mx27())
+		clk_disable_unprepare(pcdev->clk_csi);
 	writel(0, pcdev->base_csi + CSICR1);
 	if (cpu_is_mx27()) {
 		writel(0, pcdev->base_emma + PRP_CNTL);
@@ -464,9 +465,11 @@  static int mx2_camera_add_device(struct soc_camera_device *icd)
 	if (pcdev->icd)
 		return -EBUSY;
 
-	ret = clk_enable(pcdev->clk_csi);
-	if (ret < 0)
-		return ret;
+	if (cpu_is_mx27()) {
+		ret = clk_prepare_enable(pcdev->clk_csi);
+		if (ret < 0)
+			return ret;
+	}
 
 	csicr1 = CSICR1_MCLKEN;
 
@@ -1675,23 +1678,12 @@  static int __devinit mx27_camera_emma_init(struct mx2_camera_dev *pcdev)
 		goto exit_iounmap;
 	}
 
-	pcdev->clk_emma = clk_get(NULL, "emma");
-	if (IS_ERR(pcdev->clk_emma)) {
-		err = PTR_ERR(pcdev->clk_emma);
-		goto exit_free_irq;
-	}
-
-	clk_enable(pcdev->clk_emma);
-
 	err = mx27_camera_emma_prp_reset(pcdev);
 	if (err)
-		goto exit_clk_emma_put;
+		goto exit_free_irq;
 
 	return err;
 
-exit_clk_emma_put:
-	clk_disable(pcdev->clk_emma);
-	clk_put(pcdev->clk_emma);
 exit_free_irq:
 	free_irq(pcdev->irq_emma, pcdev);
 exit_iounmap:
@@ -1714,6 +1706,7 @@  static int __devinit mx2_camera_probe(struct platform_device *pdev)
 
 	res_csi = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq_csi = platform_get_irq(pdev, 0);
+
 	if (res_csi == NULL || irq_csi < 0) {
 		dev_err(&pdev->dev, "Missing platform resources data\n");
 		err = -ENODEV;
@@ -1727,11 +1720,26 @@  static int __devinit mx2_camera_probe(struct platform_device *pdev)
 		goto exit;
 	}
 
-	pcdev->clk_csi = clk_get(&pdev->dev, NULL);
-	if (IS_ERR(pcdev->clk_csi)) {
-		dev_err(&pdev->dev, "Could not get csi clock\n");
-		err = PTR_ERR(pcdev->clk_csi);
-		goto exit_kfree;
+	if (cpu_is_mx27()) {
+		pcdev->clk_csi = devm_clk_get(&pdev->dev, "ahb");
+		if (IS_ERR(pcdev->clk_csi)) {
+			dev_err(&pdev->dev, "Could not get csi clock\n");
+			err = PTR_ERR(pcdev->clk_csi);
+			goto exit_kfree;
+		}
+		pcdev->clk_emma_ipg = devm_clk_get(&pdev->dev, "emma-ipg");
+		if (IS_ERR(pcdev->clk_emma_ipg)) {
+			err = PTR_ERR(pcdev->clk_emma_ipg);
+			goto exit_kfree;
+		}
+		pcdev->clk_emma_ahb = devm_clk_get(&pdev->dev, "emma-ahb");
+		if (IS_ERR(pcdev->clk_emma_ahb)) {
+			err = PTR_ERR(pcdev->clk_emma_ahb);
+			goto exit_kfree;
+		}
+		clk_prepare_enable(pcdev->clk_csi);
+		clk_prepare_enable(pcdev->clk_emma_ipg);
+		clk_prepare_enable(pcdev->clk_emma_ahb);
 	}
 
 	pcdev->res_csi = res_csi;
@@ -1827,8 +1835,8 @@  exit_free_emma:
 eallocctx:
 	if (cpu_is_mx27()) {
 		free_irq(pcdev->irq_emma, pcdev);
-		clk_disable(pcdev->clk_emma);
-		clk_put(pcdev->clk_emma);
+		clk_disable_unprepare(pcdev->clk_emma_ipg);
+		clk_disable_unprepare(pcdev->clk_emma_ahb);
 		iounmap(pcdev->base_emma);
 		release_mem_region(pcdev->res_emma->start, resource_size(pcdev->res_emma));
 	}
@@ -1840,7 +1848,11 @@  exit_iounmap:
 exit_release:
 	release_mem_region(res_csi->start, resource_size(res_csi));
 exit_dma_free:
-	clk_put(pcdev->clk_csi);
+	if (cpu_is_mx27()) {
+		clk_disable_unprepare(pcdev->clk_emma_ipg);
+		clk_disable_unprepare(pcdev->clk_emma_ahb);
+		clk_disable_unprepare(pcdev->clk_csi);
+	}
 exit_kfree:
 	kfree(pcdev);
 exit:
@@ -1854,7 +1866,6 @@  static int __devexit mx2_camera_remove(struct platform_device *pdev)
 			struct mx2_camera_dev, soc_host);
 	struct resource *res;
 
-	clk_put(pcdev->clk_csi);
 	if (cpu_is_mx25())
 		free_irq(pcdev->irq_csi, pcdev);
 	if (cpu_is_mx27())
@@ -1867,8 +1878,8 @@  static int __devexit mx2_camera_remove(struct platform_device *pdev)
 	iounmap(pcdev->base_csi);
 
 	if (cpu_is_mx27()) {
-		clk_disable(pcdev->clk_emma);
-		clk_put(pcdev->clk_emma);
+		clk_disable_unprepare(pcdev->clk_emma_ipg);
+		clk_disable_unprepare(pcdev->clk_emma_ahb);
 		iounmap(pcdev->base_emma);
 		res = pcdev->res_emma;
 		release_mem_region(res->start, resource_size(res));