MIPS: Alchemy: add missing platform_set_drvdata() in au1550nd_probe()

From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Add missing platform_set_drvdata() in au1550nd_probe(), otherwise
calling platform_get_drvdata() in remove returns NULL.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
---
 drivers/mtd/nand/au1550nd.c | 2 ++
 1 file changed, 2 insertions(+)

On Mon, Nov 11, 2013 at 02:18:29PM +0800, Wei Yongjun wrote:
> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> 
> Add missing platform_set_drvdata() in au1550nd_probe(), otherwise
> calling platform_get_drvdata() in remove returns NULL.

An alternative solution: just allocate ctx with devm_kzalloc(). Then you
don't have to kfree() it at all.

I don't mind one solution over the other too much. Let me know which
you'd prefer.

> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> ---
>  drivers/mtd/nand/au1550nd.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/mtd/nand/au1550nd.c b/drivers/mtd/nand/au1550nd.c
> index ae8dd7c..909b673 100644
> --- a/drivers/mtd/nand/au1550nd.c
> +++ b/drivers/mtd/nand/au1550nd.c
> @@ -480,6 +480,8 @@ static int au1550nd_probe(struct platform_device *pdev)
>  
>  	mtd_device_register(&ctx->info, pd->parts, pd->num_parts);
>  
> +	platform_set_drvdata(pdev, ctx);
> +

Personally, I'd choose to call platform_set_drvdata() earlier in the
probe routine (e.g., immediately after its allocation), in case we end
up calling platform_get_drvdata() from some sub-routine in the future.

>  	return 0;
>  
>  out3:
> 

Brian

On Wednesday, November 27, 2013 8:50 AM, Brian Norris wrote:

Hi Brian Norris,

I added my questions as below. :-)

> On Mon, Nov 11, 2013 at 02:18:29PM +0800, Wei Yongjun wrote:
> > From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> >
> > Add missing platform_set_drvdata() in au1550nd_probe(), otherwise
> > calling platform_get_drvdata() in remove returns NULL.
> 
> An alternative solution: just allocate ctx with devm_kzalloc().Then you
> don't have to kfree() it at all.

Even if devm_kzalloc() is used, missing platform_set_drvdata() will
be still necessary.

static int au1550nd_remove(struct platform_device *pdev)
{
	struct au1550nd_ctx *ctx = platform_get_drvdata(pdev);
	.....

	nand_release(&ctx->info);

'ctx' is still used. Also, in order to use 'ctx',
platform_get_drvdata(pdev) should be called.

> 
> I don't mind one solution over the other too much. Let me know which
> you'd prefer.
> 
> > Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> > ---
> >  drivers/mtd/nand/au1550nd.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/mtd/nand/au1550nd.c b/drivers/mtd/nand/au1550nd.c
> > index ae8dd7c..909b673 100644
> > --- a/drivers/mtd/nand/au1550nd.c
> > +++ b/drivers/mtd/nand/au1550nd.c
> > @@ -480,6 +480,8 @@ static int au1550nd_probe(struct platform_device *pdev)
> >
> >  	mtd_device_register(&ctx->info, pd->parts, pd->num_parts);
> >
> > +	platform_set_drvdata(pdev, ctx);
> > +
> 
> Personally, I'd choose to call platform_set_drvdata() earlier in the
> probe routine (e.g., immediately after its allocation), in case we end
> up calling platform_get_drvdata() from some sub-routine in the future.

Do you mean the following?
But, most drivers calls platform_set_drvdata() later in the probe routine.

static int au1550nd_probe(struct platform_device *pdev)
{
        struct au1550nd_platdata *pd;
        struct au1550nd_ctx *ctx;
        struct nand_chip *this;
        struct resource *r;
        int ret, cs;

        pd = dev_get_platdata(&pdev->dev);
        if (!pd) {
                dev_err(&pdev->dev, "missing platform data\n");
                return -ENODEV;
        }

        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
        if (!ctx) {
                dev_err(&pdev->dev, "no memory for NAND context\n");
                return -ENOMEM;
        }

+	platform_set_drvdata(pdev, ctx);
+

Best regards,
Jingoo Han

Hi Jingoo,

On Wed, Nov 27, 2013 at 09:14:18AM +0900, Jingoo Han wrote:
> On Wednesday, November 27, 2013 8:50 AM, Brian Norris wrote:
> > On Mon, Nov 11, 2013 at 02:18:29PM +0800, Wei Yongjun wrote:
> > > From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> > >
> > > Add missing platform_set_drvdata() in au1550nd_probe(), otherwise
> > > calling platform_get_drvdata() in remove returns NULL.
> > 
> > An alternative solution: just allocate ctx with devm_kzalloc().Then you
> > don't have to kfree() it at all.
> 
> Even if devm_kzalloc() is used, missing platform_set_drvdata() will
> be still necessary.
> 
> static int au1550nd_remove(struct platform_device *pdev)
> {
> 	struct au1550nd_ctx *ctx = platform_get_drvdata(pdev);
> 	.....
> 
> 	nand_release(&ctx->info);
> 
> 'ctx' is still used. Also, in order to use 'ctx',
> platform_get_drvdata(pdev) should be called.

Ah, I overlooked that. Thanks. In that case, you still have to do
something like this patch, and devm_kzalloc() can be left for another
day (or not done at all).

> > 
> > I don't mind one solution over the other too much. Let me know which
> > you'd prefer.
> > 
> > > Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> > > ---
> > >  drivers/mtd/nand/au1550nd.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/mtd/nand/au1550nd.c b/drivers/mtd/nand/au1550nd.c
> > > index ae8dd7c..909b673 100644
> > > --- a/drivers/mtd/nand/au1550nd.c
> > > +++ b/drivers/mtd/nand/au1550nd.c
> > > @@ -480,6 +480,8 @@ static int au1550nd_probe(struct platform_device *pdev)
> > >
> > >  	mtd_device_register(&ctx->info, pd->parts, pd->num_parts);
> > >
> > > +	platform_set_drvdata(pdev, ctx);
> > > +
> > 
> > Personally, I'd choose to call platform_set_drvdata() earlier in the
> > probe routine (e.g., immediately after its allocation), in case we end
> > up calling platform_get_drvdata() from some sub-routine in the future.
> 
> Do you mean the following?
> But, most drivers calls platform_set_drvdata() later in the probe routine.

I wouldn't say "most." An unscientific survey seemed to show some
variation, with no clear pattern.

> static int au1550nd_probe(struct platform_device *pdev)
> {
>         struct au1550nd_platdata *pd;
>         struct au1550nd_ctx *ctx;
>         struct nand_chip *this;
>         struct resource *r;
>         int ret, cs;
> 
>         pd = dev_get_platdata(&pdev->dev);
>         if (!pd) {
>                 dev_err(&pdev->dev, "missing platform data\n");
>                 return -ENODEV;
>         }
> 
>         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
>         if (!ctx) {
>                 dev_err(&pdev->dev, "no memory for NAND context\n");
>                 return -ENOMEM;
>         }
> 
> +	platform_set_drvdata(pdev, ctx);
> +

Yes, that looks better to me.

Brian

On Tue, Nov 26, 2013 at 07:35:55PM -0800, Brian Norris wrote:
> On Wed, Nov 27, 2013 at 09:14:18AM +0900, Jingoo Han wrote:
> > On Wednesday, November 27, 2013 8:50 AM, Brian Norris wrote:
> > > On Mon, Nov 11, 2013 at 02:18:29PM +0800, Wei Yongjun wrote:
> > > > --- a/drivers/mtd/nand/au1550nd.c
> > > > +++ b/drivers/mtd/nand/au1550nd.c
> > > > @@ -480,6 +480,8 @@ static int au1550nd_probe(struct platform_device *pdev)
> > > >
> > > >  	mtd_device_register(&ctx->info, pd->parts, pd->num_parts);
> > > >
> > > > +	platform_set_drvdata(pdev, ctx);
> > > > +
> > > 
> > > Personally, I'd choose to call platform_set_drvdata() earlier in the
> > > probe routine (e.g., immediately after its allocation), in case we end
> > > up calling platform_get_drvdata() from some sub-routine in the future.
> > 
> > Do you mean the following?
> > But, most drivers calls platform_set_drvdata() later in the probe routine.
> 
> I wouldn't say "most." An unscientific survey seemed to show some
> variation, with no clear pattern.

I'm just pushing the original patch, since this isn't really a big
issue.

Pushed to l2-mtd.git. I reworked the $subject, since this isn't really
about MIPS at all. Thanks Wei and Jingoo.

Brian