diff mbox

mtd: nand: orion: fix clk handling

Message ID 20170312213406.20987-1-gmbnomis@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Simon Baatz March 12, 2017, 9:34 p.m. UTC
The clk handling in orion_nand.c had two problems:

- In the probe function, clk_put() was called for an enabled clock,
  which violates the API (see documentation for clk_put() in
  include/linux/clk.h)

- In the error path of the probe function, clk_put() could be called
  twice for the same clock.

In order to clean this up, use the managed function devm_clk_get() and
store the pointer to the clk in the driver data.

Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
Cc: <stable@vger.kernel.org> # v4.5+
Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
---
 drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

Comments

Uwe Kleine-König March 13, 2017, 7:12 a.m. UTC | #1
Hello Simon,

On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:
> The clk handling in orion_nand.c had two problems:
> 
> - In the probe function, clk_put() was called for an enabled clock,
>   which violates the API (see documentation for clk_put() in
>   include/linux/clk.h)
> 
> - In the error path of the probe function, clk_put() could be called
>   twice for the same clock.
> 
> In order to clean this up, use the managed function devm_clk_get() and
> store the pointer to the clk in the driver data.
> 
> Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> Cc: <stable@vger.kernel.org> # v4.5+
> Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> ---
>  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
>  1 file changed, 21 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> index 4a91c5d000be..b355aa738fae 100644
> --- a/drivers/mtd/nand/orion_nand.c
> +++ b/drivers/mtd/nand/orion_nand.c
> @@ -23,6 +23,11 @@
>  #include <asm/sizes.h>
>  #include <linux/platform_data/mtd-orion_nand.h>
>  
> +struct orion_nand_info {
> +	struct nand_chip chip;
> +	struct clk       *clk;
> +};
> +
>  static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
>  {
>  	struct nand_chip *nc = mtd_to_nand(mtd);
> @@ -75,20 +80,21 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
>  
>  static int __init orion_nand_probe(struct platform_device *pdev)
>  {
> +	struct orion_nand_info *info;
>  	struct mtd_info *mtd;
>  	struct nand_chip *nc;
>  	struct orion_nand_data *board;
>  	struct resource *res;
> -	struct clk *clk;
>  	void __iomem *io_base;
>  	int ret = 0;
>  	u32 val = 0;
>  
> -	nc = devm_kzalloc(&pdev->dev,
> -			sizeof(struct nand_chip),
> +	info = devm_kzalloc(&pdev->dev,
> +			sizeof(struct orion_nand_info),
>  			GFP_KERNEL);
> -	if (!nc)
> +	if (!info)
>  		return -ENOMEM;
> +	nc = &info->chip;
>  	mtd = nand_to_mtd(nc);
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -145,15 +151,13 @@ static int __init orion_nand_probe(struct platform_device *pdev)
>  	if (board->dev_ready)
>  		nc->dev_ready = board->dev_ready;
>  
> -	platform_set_drvdata(pdev, mtd);
> +	platform_set_drvdata(pdev, info);
>  
>  	/* Not all platforms can gate the clock, so it is not
>  	   an error if the clock does not exists. */
> -	clk = clk_get(&pdev->dev, NULL);
> -	if (!IS_ERR(clk)) {
> -		clk_prepare_enable(clk);
> -		clk_put(clk);
> -	}
> +	info->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (!IS_ERR(info->clk))
> +		clk_prepare_enable(info->clk);

Orthogonal to your patch I suggest:

-	info->clk = devm_clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(info->clk))
-		clk_prepare_enable(info->clk);
+	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
+	if (IS_ERR(info->clk)) {
+		ret = PTR_ERR(info->clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(...);
+		return ret;
+	}

to correct error handling.
(I didn't check if a plain return is right here, and also other users of
info->clk need adaption.)

Best regards
Uwe
Simon Baatz March 13, 2017, 8:43 p.m. UTC | #2
Hello Uwe,

On Mon, Mar 13, 2017 at 08:12:41AM +0100, Uwe Kleine-K?nig wrote:
> Hello Simon,
> 
> On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:
> > The clk handling in orion_nand.c had two problems:
> > 
> > - In the probe function, clk_put() was called for an enabled clock,
> >   which violates the API (see documentation for clk_put() in
> >   include/linux/clk.h)
> > 
> > - In the error path of the probe function, clk_put() could be called
> >   twice for the same clock.
> > 
> > In order to clean this up, use the managed function devm_clk_get() and
> > store the pointer to the clk in the driver data.

...

> >  	/* Not all platforms can gate the clock, so it is not
> >  	   an error if the clock does not exists. */
> > -	clk = clk_get(&pdev->dev, NULL);
> > -	if (!IS_ERR(clk)) {
> > -		clk_prepare_enable(clk);
> > -		clk_put(clk);
> > -	}
> > +	info->clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (!IS_ERR(info->clk))
> > +		clk_prepare_enable(info->clk);
> 
> Orthogonal to your patch I suggest:
> 
> -	info->clk = devm_clk_get(&pdev->dev, NULL);
> -	if (!IS_ERR(info->clk))
> -		clk_prepare_enable(info->clk);
> +	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> +	if (IS_ERR(info->clk)) {
> +		ret = PTR_ERR(info->clk);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(...);
> +		return ret;
> +	}
> 
> to correct error handling.
> (I didn't check if a plain return is right here, and also other users of
> info->clk need adaption.)

Nice! However, I can't find a devm_clk_get_optional() anywhere(?) Is
it in some upcoming patch?


- Simon
Uwe Kleine-König March 13, 2017, 8:58 p.m. UTC | #3
Hello Simon,

On Mon, Mar 13, 2017 at 09:43:44PM +0100, Simon Baatz wrote:
> Hello Uwe,
> 
> On Mon, Mar 13, 2017 at 08:12:41AM +0100, Uwe Kleine-K?nig wrote:
> > Hello Simon,
> > 
> > On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:
> > > The clk handling in orion_nand.c had two problems:
> > > 
> > > - In the probe function, clk_put() was called for an enabled clock,
> > >   which violates the API (see documentation for clk_put() in
> > >   include/linux/clk.h)
> > > 
> > > - In the error path of the probe function, clk_put() could be called
> > >   twice for the same clock.
> > > 
> > > In order to clean this up, use the managed function devm_clk_get() and
> > > store the pointer to the clk in the driver data.
> 
> ...
> 
> > >  	/* Not all platforms can gate the clock, so it is not
> > >  	   an error if the clock does not exists. */
> > > -	clk = clk_get(&pdev->dev, NULL);
> > > -	if (!IS_ERR(clk)) {
> > > -		clk_prepare_enable(clk);
> > > -		clk_put(clk);
> > > -	}
> > > +	info->clk = devm_clk_get(&pdev->dev, NULL);
> > > +	if (!IS_ERR(info->clk))
> > > +		clk_prepare_enable(info->clk);
> > 
> > Orthogonal to your patch I suggest:
> > 
> > -	info->clk = devm_clk_get(&pdev->dev, NULL);
> > -	if (!IS_ERR(info->clk))
> > -		clk_prepare_enable(info->clk);
> > +	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> > +	if (IS_ERR(info->clk)) {
> > +		ret = PTR_ERR(info->clk);
> > +		if (ret != -EPROBE_DEFER)
> > +			dev_err(...);
> > +		return ret;
> > +	}
> > 
> > to correct error handling.
> > (I didn't check if a plain return is right here, and also other users of
> > info->clk need adaption.)
> 
> Nice! However, I can't find a devm_clk_get_optional() anywhere(?) Is
> it in some upcoming patch?

Oh really. I was sure I already made use of it. Probably consfused it
with the gpio or regulator API which have such variants. (But be aware,
they are sematically different. If you look for a place to copy from
please stick to the gpio sematic.)

Then either send a patch creating clk_get_optional and friends, or only
ignore -ENODEV but propagate the other error values. (Maybe the most
rational path is to do both and switch the driver once clk_get_optional
is available.)

Best regards
Uwe
Boris BREZILLON March 16, 2017, 9:05 a.m. UTC | #4
Hi Simon,

On Sun, 12 Mar 2017 22:34:06 +0100
Simon Baatz <gmbnomis@gmail.com> wrote:

> The clk handling in orion_nand.c had two problems:
> 
> - In the probe function, clk_put() was called for an enabled clock,
>   which violates the API (see documentation for clk_put() in
>   include/linux/clk.h)
> 
> - In the error path of the probe function, clk_put() could be called
>   twice for the same clock.
> 
> In order to clean this up, use the managed function devm_clk_get() and
> store the pointer to the clk in the driver data.
> 
> Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> Cc: <stable@vger.kernel.org> # v4.5+
> Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> ---
>  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
>  1 file changed, 21 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> index 4a91c5d000be..b355aa738fae 100644
> --- a/drivers/mtd/nand/orion_nand.c
> +++ b/drivers/mtd/nand/orion_nand.c
> @@ -23,6 +23,11 @@
>  #include <asm/sizes.h>
>  #include <linux/platform_data/mtd-orion_nand.h>
>  
> +struct orion_nand_info {
> +	struct nand_chip chip;
> +	struct clk       *clk;

Can we avoid this kind of alignment, which will not be preserved if
someone adds a new field with a type that is longer than "struct
nand_chip "?

Regards,

Boris
Boris BREZILLON March 16, 2017, 9:12 a.m. UTC | #5
On Mon, 13 Mar 2017 08:12:41 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> Hello Simon,
> 
> On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:
> > The clk handling in orion_nand.c had two problems:
> > 
> > - In the probe function, clk_put() was called for an enabled clock,
> >   which violates the API (see documentation for clk_put() in
> >   include/linux/clk.h)
> > 
> > - In the error path of the probe function, clk_put() could be called
> >   twice for the same clock.
> > 
> > In order to clean this up, use the managed function devm_clk_get() and
> > store the pointer to the clk in the driver data.
> > 
> > Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> > Cc: <stable@vger.kernel.org> # v4.5+
> > Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> > ---
> >  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
> >  1 file changed, 21 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> > index 4a91c5d000be..b355aa738fae 100644
> > --- a/drivers/mtd/nand/orion_nand.c
> > +++ b/drivers/mtd/nand/orion_nand.c
> > @@ -23,6 +23,11 @@
> >  #include <asm/sizes.h>
> >  #include <linux/platform_data/mtd-orion_nand.h>
> >  
> > +struct orion_nand_info {
> > +	struct nand_chip chip;
> > +	struct clk       *clk;
> > +};
> > +
> >  static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
> >  {
> >  	struct nand_chip *nc = mtd_to_nand(mtd);
> > @@ -75,20 +80,21 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> >  
> >  static int __init orion_nand_probe(struct platform_device *pdev)
> >  {
> > +	struct orion_nand_info *info;
> >  	struct mtd_info *mtd;
> >  	struct nand_chip *nc;
> >  	struct orion_nand_data *board;
> >  	struct resource *res;
> > -	struct clk *clk;
> >  	void __iomem *io_base;
> >  	int ret = 0;
> >  	u32 val = 0;
> >  
> > -	nc = devm_kzalloc(&pdev->dev,
> > -			sizeof(struct nand_chip),
> > +	info = devm_kzalloc(&pdev->dev,
> > +			sizeof(struct orion_nand_info),
> >  			GFP_KERNEL);
> > -	if (!nc)
> > +	if (!info)
> >  		return -ENOMEM;
> > +	nc = &info->chip;
> >  	mtd = nand_to_mtd(nc);
> >  
> >  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > @@ -145,15 +151,13 @@ static int __init orion_nand_probe(struct platform_device *pdev)
> >  	if (board->dev_ready)
> >  		nc->dev_ready = board->dev_ready;
> >  
> > -	platform_set_drvdata(pdev, mtd);
> > +	platform_set_drvdata(pdev, info);
> >  
> >  	/* Not all platforms can gate the clock, so it is not
> >  	   an error if the clock does not exists. */
> > -	clk = clk_get(&pdev->dev, NULL);
> > -	if (!IS_ERR(clk)) {
> > -		clk_prepare_enable(clk);
> > -		clk_put(clk);
> > -	}
> > +	info->clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (!IS_ERR(info->clk))
> > +		clk_prepare_enable(info->clk);  
> 
> Orthogonal to your patch I suggest:
> 
> -	info->clk = devm_clk_get(&pdev->dev, NULL);
> -	if (!IS_ERR(info->clk))
> -		clk_prepare_enable(info->clk);
> +	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> +	if (IS_ERR(info->clk)) {
> +		ret = PTR_ERR(info->clk);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(...);
> +		return ret;
> +	}
> 

In the meantime, maybe you can do:

	info->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(info->clk)) {
		ret = PTR_ERR(info->clk);

		if (ret == -ENOENT) {
			/*
			 * This clk is optional, assign it to NULL when
			 * it's not present.
			 */
			info->clk = NULL;
		} else {
			if (ret == -EPROBE_DEFER)
				dev_err(...);

			return ret;
		}
	}

This way, you won't have to check the info->clk value when you call
clk_prepare_enable() or clk_disable_unprepare().
Simon Baatz March 16, 2017, 9:44 p.m. UTC | #6
Hello Boris,

On Thu, Mar 16, 2017 at 10:05:39AM +0100, Boris Brezillon wrote:
> Hi Simon,
> 
> On Sun, 12 Mar 2017 22:34:06 +0100
> Simon Baatz <gmbnomis@gmail.com> wrote:
> 
> > The clk handling in orion_nand.c had two problems:
> > 
> > - In the probe function, clk_put() was called for an enabled clock,
> >   which violates the API (see documentation for clk_put() in
> >   include/linux/clk.h)
> > 
> > - In the error path of the probe function, clk_put() could be called
> >   twice for the same clock.
> > 
> > In order to clean this up, use the managed function devm_clk_get() and
> > store the pointer to the clk in the driver data.
> > 
> > Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> > Cc: <stable@vger.kernel.org> # v4.5+
> > Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> > ---
> >  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
> >  1 file changed, 21 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> > index 4a91c5d000be..b355aa738fae 100644
> > --- a/drivers/mtd/nand/orion_nand.c
> > +++ b/drivers/mtd/nand/orion_nand.c
> > @@ -23,6 +23,11 @@
> >  #include <asm/sizes.h>
> >  #include <linux/platform_data/mtd-orion_nand.h>
> >  
> > +struct orion_nand_info {
> > +	struct nand_chip chip;
> > +	struct clk       *clk;
> 
> Can we avoid this kind of alignment, which will not be preserved if
> someone adds a new field with a type that is longer than "struct
> nand_chip "?
> 

Sure. I will change that in v2.


- Simon
Simon Baatz March 16, 2017, 9:50 p.m. UTC | #7
On Thu, Mar 16, 2017 at 10:12:11AM +0100, Boris Brezillon wrote:
> On Mon, 13 Mar 2017 08:12:41 +0100
> Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> 
> > Hello Simon,
> > 
> > On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:
> > > The clk handling in orion_nand.c had two problems:
> > > 
> > > - In the probe function, clk_put() was called for an enabled clock,
> > >   which violates the API (see documentation for clk_put() in
> > >   include/linux/clk.h)
> > > 
> > > - In the error path of the probe function, clk_put() could be called
> > >   twice for the same clock.
> > > 
> > > In order to clean this up, use the managed function devm_clk_get() and
> > > store the pointer to the clk in the driver data.
> > > 
> > > Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> > > Cc: <stable@vger.kernel.org> # v4.5+
> > > Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> > > ---
> > >  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
> > >  1 file changed, 21 insertions(+), 21 deletions(-)
> > > 
> > > diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> > > index 4a91c5d000be..b355aa738fae 100644
> > > --- a/drivers/mtd/nand/orion_nand.c
> > > +++ b/drivers/mtd/nand/orion_nand.c
> > > @@ -23,6 +23,11 @@
> > >  #include <asm/sizes.h>
> > >  #include <linux/platform_data/mtd-orion_nand.h>
> > >  
> > > +struct orion_nand_info {
> > > +	struct nand_chip chip;
> > > +	struct clk       *clk;
> > > +};
> > > +
> > >  static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
> > >  {
> > >  	struct nand_chip *nc = mtd_to_nand(mtd);
> > > @@ -75,20 +80,21 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> > >  
> > >  static int __init orion_nand_probe(struct platform_device *pdev)
> > >  {
> > > +	struct orion_nand_info *info;
> > >  	struct mtd_info *mtd;
> > >  	struct nand_chip *nc;
> > >  	struct orion_nand_data *board;
> > >  	struct resource *res;
> > > -	struct clk *clk;
> > >  	void __iomem *io_base;
> > >  	int ret = 0;
> > >  	u32 val = 0;
> > >  
> > > -	nc = devm_kzalloc(&pdev->dev,
> > > -			sizeof(struct nand_chip),
> > > +	info = devm_kzalloc(&pdev->dev,
> > > +			sizeof(struct orion_nand_info),
> > >  			GFP_KERNEL);
> > > -	if (!nc)
> > > +	if (!info)
> > >  		return -ENOMEM;
> > > +	nc = &info->chip;
> > >  	mtd = nand_to_mtd(nc);
> > >  
> > >  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > @@ -145,15 +151,13 @@ static int __init orion_nand_probe(struct platform_device *pdev)
> > >  	if (board->dev_ready)
> > >  		nc->dev_ready = board->dev_ready;
> > >  
> > > -	platform_set_drvdata(pdev, mtd);
> > > +	platform_set_drvdata(pdev, info);
> > >  
> > >  	/* Not all platforms can gate the clock, so it is not
> > >  	   an error if the clock does not exists. */
> > > -	clk = clk_get(&pdev->dev, NULL);
> > > -	if (!IS_ERR(clk)) {
> > > -		clk_prepare_enable(clk);
> > > -		clk_put(clk);
> > > -	}
> > > +	info->clk = devm_clk_get(&pdev->dev, NULL);
> > > +	if (!IS_ERR(info->clk))
> > > +		clk_prepare_enable(info->clk);  
> > 
> > Orthogonal to your patch I suggest:
> > 
> > -	info->clk = devm_clk_get(&pdev->dev, NULL);
> > -	if (!IS_ERR(info->clk))
> > -		clk_prepare_enable(info->clk);
> > +	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> > +	if (IS_ERR(info->clk)) {
> > +		ret = PTR_ERR(info->clk);
> > +		if (ret != -EPROBE_DEFER)
> > +			dev_err(...);
> > +		return ret;
> > +	}
> > 
> 
> In the meantime, maybe you can do:
> 
> 	info->clk = devm_clk_get(&pdev->dev, NULL);
> 	if (IS_ERR(info->clk)) {
> 		ret = PTR_ERR(info->clk);
> 
> 		if (ret == -ENOENT) {
> 			/*
> 			 * This clk is optional, assign it to NULL when
> 			 * it's not present.
> 			 */
> 			info->clk = NULL;
> 		} else {
> 			if (ret == -EPROBE_DEFER)
> 				dev_err(...);
> 
> 			return ret;
> 		}
> 	}
> 
> This way, you won't have to check the info->clk value when you call
> clk_prepare_enable() or clk_disable_unprepare().
> 

Yes, this makes things simpler. I will add a second patch improving
the error handling in v2 as you and Uwe suggested.


- Simon
Boris BREZILLON March 17, 2017, 6:36 a.m. UTC | #8
On Thu, 16 Mar 2017 22:50:31 +0100
Simon Baatz <gmbnomis@gmail.com> wrote:

> On Thu, Mar 16, 2017 at 10:12:11AM +0100, Boris Brezillon wrote:
> > On Mon, 13 Mar 2017 08:12:41 +0100
> > Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> >   
> > > Hello Simon,
> > > 
> > > On Sun, Mar 12, 2017 at 10:34:06PM +0100, Simon Baatz wrote:  
> > > > The clk handling in orion_nand.c had two problems:
> > > > 
> > > > - In the probe function, clk_put() was called for an enabled clock,
> > > >   which violates the API (see documentation for clk_put() in
> > > >   include/linux/clk.h)
> > > > 
> > > > - In the error path of the probe function, clk_put() could be called
> > > >   twice for the same clock.
> > > > 
> > > > In order to clean this up, use the managed function devm_clk_get() and
> > > > store the pointer to the clk in the driver data.
> > > > 
> > > > Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
> > > > Cc: <stable@vger.kernel.org> # v4.5+
> > > > Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
> > > > ---
> > > >  drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
> > > >  1 file changed, 21 insertions(+), 21 deletions(-)
> > > > 
> > > > diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
> > > > index 4a91c5d000be..b355aa738fae 100644
> > > > --- a/drivers/mtd/nand/orion_nand.c
> > > > +++ b/drivers/mtd/nand/orion_nand.c
> > > > @@ -23,6 +23,11 @@
> > > >  #include <asm/sizes.h>
> > > >  #include <linux/platform_data/mtd-orion_nand.h>
> > > >  
> > > > +struct orion_nand_info {
> > > > +	struct nand_chip chip;
> > > > +	struct clk       *clk;
> > > > +};
> > > > +
> > > >  static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
> > > >  {
> > > >  	struct nand_chip *nc = mtd_to_nand(mtd);
> > > > @@ -75,20 +80,21 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> > > >  
> > > >  static int __init orion_nand_probe(struct platform_device *pdev)
> > > >  {
> > > > +	struct orion_nand_info *info;
> > > >  	struct mtd_info *mtd;
> > > >  	struct nand_chip *nc;
> > > >  	struct orion_nand_data *board;
> > > >  	struct resource *res;
> > > > -	struct clk *clk;
> > > >  	void __iomem *io_base;
> > > >  	int ret = 0;
> > > >  	u32 val = 0;
> > > >  
> > > > -	nc = devm_kzalloc(&pdev->dev,
> > > > -			sizeof(struct nand_chip),
> > > > +	info = devm_kzalloc(&pdev->dev,
> > > > +			sizeof(struct orion_nand_info),
> > > >  			GFP_KERNEL);
> > > > -	if (!nc)
> > > > +	if (!info)
> > > >  		return -ENOMEM;
> > > > +	nc = &info->chip;
> > > >  	mtd = nand_to_mtd(nc);
> > > >  
> > > >  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > > @@ -145,15 +151,13 @@ static int __init orion_nand_probe(struct platform_device *pdev)
> > > >  	if (board->dev_ready)
> > > >  		nc->dev_ready = board->dev_ready;
> > > >  
> > > > -	platform_set_drvdata(pdev, mtd);
> > > > +	platform_set_drvdata(pdev, info);
> > > >  
> > > >  	/* Not all platforms can gate the clock, so it is not
> > > >  	   an error if the clock does not exists. */
> > > > -	clk = clk_get(&pdev->dev, NULL);
> > > > -	if (!IS_ERR(clk)) {
> > > > -		clk_prepare_enable(clk);
> > > > -		clk_put(clk);
> > > > -	}
> > > > +	info->clk = devm_clk_get(&pdev->dev, NULL);
> > > > +	if (!IS_ERR(info->clk))
> > > > +		clk_prepare_enable(info->clk);    
> > > 
> > > Orthogonal to your patch I suggest:
> > > 
> > > -	info->clk = devm_clk_get(&pdev->dev, NULL);
> > > -	if (!IS_ERR(info->clk))
> > > -		clk_prepare_enable(info->clk);
> > > +	info->clk = devm_clk_get_optional(&pdev->dev, NULL);
> > > +	if (IS_ERR(info->clk)) {
> > > +		ret = PTR_ERR(info->clk);
> > > +		if (ret != -EPROBE_DEFER)
> > > +			dev_err(...);
> > > +		return ret;
> > > +	}
> > >   
> > 
> > In the meantime, maybe you can do:
> > 
> > 	info->clk = devm_clk_get(&pdev->dev, NULL);
> > 	if (IS_ERR(info->clk)) {
> > 		ret = PTR_ERR(info->clk);
> > 
> > 		if (ret == -ENOENT) {
> > 			/*
> > 			 * This clk is optional, assign it to NULL when
> > 			 * it's not present.
> > 			 */
> > 			info->clk = NULL;
> > 		} else {
> > 			if (ret == -EPROBE_DEFER)

I meant != -EPROBE_DEFER here.

> > 				dev_err(...);
> > 
> > 			return ret;
> > 		}
> > 	}
> > 
> > This way, you won't have to check the info->clk value when you call
> > clk_prepare_enable() or clk_disable_unprepare().
> >   
> 
> Yes, this makes things simpler. I will add a second patch improving
> the error handling in v2 as you and Uwe suggested.
> 
> 
> - Simon
diff mbox

Patch

diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
index 4a91c5d000be..b355aa738fae 100644
--- a/drivers/mtd/nand/orion_nand.c
+++ b/drivers/mtd/nand/orion_nand.c
@@ -23,6 +23,11 @@ 
 #include <asm/sizes.h>
 #include <linux/platform_data/mtd-orion_nand.h>
 
+struct orion_nand_info {
+	struct nand_chip chip;
+	struct clk       *clk;
+};
+
 static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 {
 	struct nand_chip *nc = mtd_to_nand(mtd);
@@ -75,20 +80,21 @@  static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
 
 static int __init orion_nand_probe(struct platform_device *pdev)
 {
+	struct orion_nand_info *info;
 	struct mtd_info *mtd;
 	struct nand_chip *nc;
 	struct orion_nand_data *board;
 	struct resource *res;
-	struct clk *clk;
 	void __iomem *io_base;
 	int ret = 0;
 	u32 val = 0;
 
-	nc = devm_kzalloc(&pdev->dev,
-			sizeof(struct nand_chip),
+	info = devm_kzalloc(&pdev->dev,
+			sizeof(struct orion_nand_info),
 			GFP_KERNEL);
-	if (!nc)
+	if (!info)
 		return -ENOMEM;
+	nc = &info->chip;
 	mtd = nand_to_mtd(nc);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -145,15 +151,13 @@  static int __init orion_nand_probe(struct platform_device *pdev)
 	if (board->dev_ready)
 		nc->dev_ready = board->dev_ready;
 
-	platform_set_drvdata(pdev, mtd);
+	platform_set_drvdata(pdev, info);
 
 	/* Not all platforms can gate the clock, so it is not
 	   an error if the clock does not exists. */
-	clk = clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(clk)) {
-		clk_prepare_enable(clk);
-		clk_put(clk);
-	}
+	info->clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(info->clk))
+		clk_prepare_enable(info->clk);
 
 	ret = nand_scan(mtd, 1);
 	if (ret)
@@ -169,26 +173,22 @@  static int __init orion_nand_probe(struct platform_device *pdev)
 	return 0;
 
 no_dev:
-	if (!IS_ERR(clk)) {
-		clk_disable_unprepare(clk);
-		clk_put(clk);
-	}
+	if (!IS_ERR(info->clk))
+		clk_disable_unprepare(info->clk);
 
 	return ret;
 }
 
 static int orion_nand_remove(struct platform_device *pdev)
 {
-	struct mtd_info *mtd = platform_get_drvdata(pdev);
-	struct clk *clk;
+	struct orion_nand_info *info = platform_get_drvdata(pdev);
+	struct nand_chip *chip = &info->chip;
+	struct mtd_info *mtd = nand_to_mtd(chip);
 
 	nand_release(mtd);
 
-	clk = clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(clk)) {
-		clk_disable_unprepare(clk);
-		clk_put(clk);
-	}
+	if (!IS_ERR(info->clk))
+		clk_disable_unprepare(info->clk);
 
 	return 0;
 }