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SubjectRe: [PATCH 2/3] gpio: pxa: Fix return value of pxa_gpio_probe()
Date
Tiezhu Yang <yangtiezhu@loongson.cn> writes:

> On 05/23/2020 03:07 AM, Robert Jarzmik wrote:
>> Tiezhu Yang <yangtiezhu@loongson.cn> 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@loongson.cn>
>>> ---
>>> 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?
You're right, my bad, didn't see the test in __devm_ioremap_resource().

Cheers.

--
Robert

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