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SubjectRe: [PATCH] driver-core: platform: Avoid to return IRQ 0 in platform_get_irq()
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Hi Dmitry,


On Tuesday 05 December 2017 11:50 PM, Dmitry Torokhov wrote:
> On Tue, Dec 05, 2017 at 11:41:52PM +0530, Arvind Yadav wrote:
>> Function platform_get_irq() can return 0. Which means NO_IRQ.
>> So this change will not allow to return 0.
>>
>> This change is help to use platform_get_irq() without this,
>>
>> val = platform_get_irq();
>> if (val <= 0)
>> ret = val ? val : -ENODEV;
>>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> You need to audit the drivers and make sure you are not breaking them
> with this. I believe at least i2c designware controller on certain
> boards has DEFINE_RES_IRQ(0) which will be broken by this patch.
Yes, you are right. Few driver is using DEFINE_RES_IRQ(0).
Example:
drivers/mfd/intel-lpss.c
static const struct resource intel_lpss_dev_resources[] = {
DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"),
DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE,
"lpss_priv"),
DEFINE_RES_IRQ(0),
};
There's a bunch of platforms in the kernel that still use IRQ0. They can
suffer because
of this change. I should have mark this patch for testing.
>
>> ---
>> drivers/base/platform.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
>> index c203fb9..7b3079c 100644
>> --- a/drivers/base/platform.c
>> +++ b/drivers/base/platform.c
>> @@ -127,7 +127,7 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
>> irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
>> }
>>
>> - return r ? r->start : -ENXIO;
>> + return r && r->start ? r->start : -ENXIO;
>> #endif
>> }
>> EXPORT_SYMBOL_GPL(platform_get_irq);
>> --
>> 2.7.4
>>
> Thanks.
>
Thanks,

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