Re: [PATCH 2/3] gpio: pxa: Fix return value of pxa_gpio_probe()

[Tiezhu Yang]

On 05/23/2020 03:07 AM, Robert Jarzmik wrote:
> Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> writes:
>
> > When call function devm_platform_ioremap_resource(), we should use IS_ERR()
> > to check the return value and return PTR_ERR() if failed.
> >
> > Fixes: 542c25b7a209 ("drivers: gpio: pxa: use devm_platform_ioremap_resource()")
> > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > ---
> >   drivers/gpio/gpio-pxa.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-pxa.c b/drivers/gpio/gpio-pxa.c
> > index 1361270..0cb6600 100644
> > --- a/drivers/gpio/gpio-pxa.c
> > +++ b/drivers/gpio/gpio-pxa.c
> > @@ -660,8 +660,8 @@ static int pxa_gpio_probe(struct platform_device *pdev)
> >   	pchip->irq1 = irq1;
> >   
> >   	gpio_reg_base = devm_platform_ioremap_resource(pdev, 0);
> > -	if (!gpio_reg_base)
> > -		return -EINVAL;
> > +	if (IS_ERR(gpio_reg_base))
> > +		return PTR_ERR(gpio_reg_base);
> As far as I know, devm_platform_ioremap_resource() could return NULL which is
> not handled by this test (unless __devm_ioremap() semantics changed since I had
> a look).

Hi Robert,

In the function __devm_ioremap_resource(), if __devm_ioremap returns NULL,
it will return IOMEM_ERR_PTR(-ENOMEM).

devm_platform_ioremap_resource()
        devm_ioremap_resource()
                __devm_ioremap_resource()
                       __devm_ioremap()

static void __iomem *
__devm_ioremap_resource(struct device *dev, const struct resource *res,
            enum devm_ioremap_type type)
{
...
    dest_ptr = __devm_ioremap(dev, res->start, size, type);
    if (!dest_ptr) {
        dev_err(dev, "ioremap failed for resource %pR\n", res);
        devm_release_mem_region(dev, res->start, size);
        dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
    }

    return dest_ptr;
}

And also, we can see the comment of devm_ioremap_resource():

Usage example:

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

> Therefore, this patch is incorrect, or rather incomplete.

So I think this patch is correct, do I miss something?

Thanks,
Tiezhu Yang

> Cheers.