Hi Andrew,
On Mon, Jan 10, 2022 at 10:20 PM Andrew Lunn andrew@lunn.ch wrote:
On Mon, Jan 10, 2022 at 09:10:14PM +0100, Uwe Kleine-König wrote:
On Mon, Jan 10, 2022 at 10:54:48PM +0300, Sergey Shtylyov wrote:
This patch is based on the former Andy Shevchenko's patch:
https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shevchenko@linux....
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...The difference to gpiod_get_optional (and most other *_optional) is that you can use the NULL value as if it were a valid GPIO.
As this isn't given with for irqs, I don't think changing the return value has much sense.
We actually want platform_get_irq_optional() to look different to all the other _optional() methods because it is not equivalent. If it looks the same, developers will assume it is the same, and get themselves into trouble.
Developers already assume it is the same, and thus forget they have to check against -ENXIO instead of zero.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds