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SubjectRe: [PATCH] drm/bridge: tpd12s015: Fix irq registering in tpd12s015_probe
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On 31/10/2020 09:19, Sam Ravnborg wrote:
> Hi YueHaibing
>
> Thanks for the fix. Appreciated but please update as per comments below.
>
> On Sat, Oct 31, 2020 at 11:16:48AM +0800, YueHaibing wrote:
>> gpiod_to_irq() return negative value in case of error,
>> the existing code handle negative error codes wrongly.
>>
>> Fixes: cff5e6f7e83f ("drm/bridge: Add driver for the TI TPD12S015 HDMI level shifter")
>> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
>> ---
>> drivers/gpu/drm/bridge/ti-tpd12s015.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/ti-tpd12s015.c b/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> index 514cbf0eac75..a18d5197c16c 100644
>> --- a/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> +++ b/drivers/gpu/drm/bridge/ti-tpd12s015.c
>> @@ -160,7 +160,7 @@ static int tpd12s015_probe(struct platform_device *pdev)
>>
>> /* Register the IRQ if the HPD GPIO is IRQ-capable. */
>> tpd->hpd_irq = gpiod_to_irq(tpd->hpd_gpio);
>> - if (tpd->hpd_irq) {
>> + if (tpd->hpd_irq > 0) {
>> ret = devm_request_threaded_irq(&pdev->dev, tpd->hpd_irq, NULL,
>> tpd12s015_hpd_isr,
>> IRQF_TRIGGER_RISING |
>
> The current implmentation will skip devm_request_threaded_irq() in case
> or error - but continue with the rest of the function. So the
> driver fails to return an error code.

That is intended. If the HPD gpio supports IRQs (gpiod_to_irq returns a valid number), we use the
IRQ. If it doesn't (gpiod_to_irq returns an error), it gets polled via detect(). Both are ok.

I don't know if the gpiod_to_irq never returning 0 is something we should rely on. The docs say
gpiod_to_irq returns the irq number or an error, so I think checking for >= 0 matches the docs better.

Tomi

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