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SubjectRe: [PATCH] spi: sifive: check return value for platform_get_resource()
Aurobindo, 

On Tue, 17 Sep 2019, Aurabindo Jayamohanan wrote:

> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Tuesday, September 17, 2019 5:45 PM, Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> > On Tue, 17 Sep 2019, Baolin Wang wrote:
> >
> > > On Tue, 17 Sep 2019 at 17:12, Aurabindo Jayamohanan mail@aurabindo.in wrote:
> > >
> > > > platform_get_resource() may return NULL. If it is so, return -ENXIO
> > > >
> > > > Signed-off-by: Aurabindo Jayamohanan mail@aurabindo.in
> > > >
> > > > -------------------------------------------------------
> > > >
> > > > drivers/spi/spi-sifive.c | 6 ++++++
> > > > 1 file changed, 6 insertions(+)
> > > > diff --git a/drivers/spi/spi-sifive.c b/drivers/spi/spi-sifive.c
> > > > index 93ec2c6cdbfd..67485067a694 100644
> > > > --- a/drivers/spi/spi-sifive.c
> > > > +++ b/drivers/spi/spi-sifive.c
> > > > @@ -308,6 +308,12 @@ static int sifive_spi_probe(struct platform_device *pdev)
> > > > platform_set_drvdata(pdev, master);
> > > >
> > > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > >
> > > >
> > > > - if (!res) {
> > > >
> > > >
> > > > - dev_err(&pdev->dev, "no IOMEM resource found\\n");
> > > >
> > > >
> > > > - ret = -ENXIO;
> > > >
> > > >
> > > > - goto put_master;
> > > >
> > > >
> > > > - }
> > > >
> > > >
> > >
> > > Seems unnecessary, the devm_ioremap_resource() already validated if
> > > the resource is available.
> >
> > Just doublechecked lib/devres.c and I agree with you.
> >
> > Aurobindo, is this a patch for a real problem that you've encountered?
> >
> > - Paul
>
> Geert is right. I was just breezing through the source and found it odd since
> I noticed other instances checking for return value. Apparently none of those
> use the managed api.
>
> If you didnt already do Geert's suggestion,

Mark Brown is the maintainer, so he'd be the one to apply anything
touching these drivers.

> here is a patch:

Could you please send this as a separate E-mail?

> ____
>
> spi: sifive: use device managed api to get plaform resource

"platform resource"

>
> calls to devm_ioremap_resource() preceeded by platform_get_resource()

"Calls"

"preceded"

> may be replaced by devm_platform_ioremap_resource().

Please explain why. In this case "removing boilerplate from the code"
seems like a reasonable explanation.

>
> Signed-off-by: Aurabindo Jayamohanan <mail@aurabindo.in>
> ---
> drivers/spi/spi-sifive.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-sifive.c b/drivers/spi/spi-sifive.c
> index 93ec2c6cdbfd..c0925aa98aad 100644
> --- a/drivers/spi/spi-sifive.c
> +++ b/drivers/spi/spi-sifive.c
> @@ -292,7 +292,6 @@ sifive_spi_transfer_one(struct spi_master *master, struct spi_device *device,
> static int sifive_spi_probe(struct platform_device *pdev)
> {
> struct sifive_spi *spi;
> - struct resource *res;
> int ret, irq, num_cs;
> u32 cs_bits, max_bits_per_word;
> struct spi_master *master;
> @@ -307,8 +306,7 @@ static int sifive_spi_probe(struct platform_device *pdev)
> init_completion(&spi->done);
> platform_set_drvdata(pdev, master);
>
> - res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - spi->regs = devm_ioremap_resource(&pdev->dev, res);
> + spi->regs = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(spi->regs)) {
> ret = PTR_ERR(spi->regs);
> goto put_master;
> --
> 2.23.0
>


- Paul
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