Re: [PATCH v2 1/2] platform: make platform_get_irq_optional() optional

[Sergey Shtylyov]

Hello!

On 2/14/22 11:54 AM, Geert Uytterhoeven wrote:

[...]

>> This patch is based on the former Andy Shevchenko's patch:
>>
>> https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shevchenko@xxxxxxxxxxxxxxx/
>>
>> Currently platform_get_irq_optional() returns an error code even if IRQ
>> resource simply has not been found.  It prevents the callers from being
>> error code agnostic in their error handling:
>>
>>         ret = platform_get_irq_optional(...);
>>         if (ret < 0 && ret != -ENXIO)
>>                 return ret; // respect deferred probe
>>         if (ret > 0)
>>                 ...we get an IRQ...
>>
>> All other *_optional() APIs seem to return 0 or NULL in case an optional
>> resource is not available.  Let's follow this good example, so that the
>> callers would look like:
>>
>>         ret = platform_get_irq_optional(...);
>>         if (ret < 0)
>>                 return ret;
>>         if (ret > 0)
>>                 ...we get an IRQ...
>>
>> Reported-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
>> Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
>> ---
>> Changes in version 2:
> 
> Thanks for the update!
> 
>>  drivers/base/platform.c                  | 60 +++++++++++++++---------
> 
> The core change LGTM.

   Thanx! :-)

> I'm only looking at Renesas drivers below...
> 
>> --- a/drivers/mmc/host/sh_mmcif.c
>> +++ b/drivers/mmc/host/sh_mmcif.c
>> @@ -1465,14 +1465,14 @@ static int sh_mmcif_probe(struct platform_device *pdev)
>>         sh_mmcif_sync_reset(host);
>>         sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);
>>
>> -       name = irq[1] < 0 ? dev_name(dev) : "sh_mmc:error";
>> +       name = irq[1] <= 0 ? dev_name(dev) : "sh_mmc:error";
> 
> "== 0" should be sufficient here, if the code above would bail out
> on errors returned by platform_get_irq_optional(), which it currently
> doesn't do.
> As this adds missing error handling, this is to be fixed by a separate
> patch later?

   Yes.

[...]
>>                 ret = devm_request_threaded_irq(dev, irq[1],
>>                                                 sh_mmcif_intr, sh_mmcif_irqt,
>>                                                 0, "sh_mmc:int", host);
> 
>> --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>> +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>> @@ -439,7 +439,7 @@ static int rcar_gen3_phy_usb2_init(struct phy *p)
>>         u32 val;
>>         int ret;
>>
>> -       if (!rcar_gen3_is_any_rphy_initialized(channel) && channel->irq >= 0) {
>> +       if (!rcar_gen3_is_any_rphy_initialized(channel) && channel->irq > 0) {
>>                 INIT_WORK(&channel->work, rcar_gen3_phy_usb2_work);
>>                 ret = request_irq(channel->irq, rcar_gen3_phy_usb2_irq,
>>                                   IRQF_SHARED, dev_name(channel->dev), channel);
>> @@ -486,7 +486,7 @@ static int rcar_gen3_phy_usb2_exit(struct phy *p)
>>                 val &= ~USB2_INT_ENABLE_UCOM_INTEN;
>>         writel(val, usb2_base + USB2_INT_ENABLE);
>>
>> -       if (channel->irq >= 0 && !rcar_gen3_is_any_rphy_initialized(channel))
>> +       if (channel->irq > 0 && !rcar_gen3_is_any_rphy_initialized(channel))
>>                 free_irq(channel->irq, channel);
>>
>>         return 0;
> 
> LGTM, but note that all errors returned by platform_get_irq_optional()
> are currently ignored, even real errors, which should be propagated
> up.
> As this adds missing error handling, this is to be fixed by a separate
> patch later?

   Yes.

>> --- a/drivers/thermal/rcar_gen3_thermal.c
>> +++ b/drivers/thermal/rcar_gen3_thermal.c
>> @@ -432,6 +432,8 @@ static int rcar_gen3_thermal_request_irqs(struct rcar_gen3_thermal_priv *priv,
>>                 irq = platform_get_irq_optional(pdev, i);
>>                 if (irq < 0)
>>                         return irq;
>> +               if (!irq)
>> +                       return -ENXIO;
> 
> While correct, and preserving existing behavior, this looks strange
> to me.  Probably this should return zero instead (i.e. the check
> above should be changed to "<= 0"), and the caller should start caring
> about and propagating up real errors.

   Hm, you're right... should be <= 0 there, it seems.

> As this adds missing error handling, this is to be fixed by a separate
> patch later?

   Propagating errors from the probe() method is a matter of separate patch, yes.

>>
>>                 irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
>>                                          dev_name(dev), i);
>> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
>> index fb65dc601b23..328ab074fd89 100644
> 
>> --- a/drivers/tty/serial/sh-sci.c
>> +++ b/drivers/tty/serial/sh-sci.c
> 
> I think you missed
> 
>     #define SCIx_IRQ_IS_MUXED(port)                 \
>             ((port)->irqs[SCIx_ERI_IRQ] ==  \
>              (port)->irqs[SCIx_RXI_IRQ]) || \
>             ((port)->irqs[SCIx_ERI_IRQ] &&  \
>              ((port)->irqs[SCIx_RXI_IRQ] < 0))
> 
> above? The last condition should become "<= 0".

   Yes, probably... TY!

> Gr{oetje,eeting}s,
> 
>                         Geert

MBR, Sergey