Hello, 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@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... 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. In my eyes the problem with platform_get_irq() and platform_get_irq_optional() is that someone considered it was a good idea that a global function emits an error message. The problem is, that's only true most of the time. (Sometimes the caller can handle an error (here: the absence of an irq) just fine, sometimes the generic error message just isn't as good as a message by the caller could be. (here: The caller could emit "TX irq not found" which is a much nicer message than "IRQ index 5 not found".) My suggestion would be to keep the return value of platform_get_irq_optional() as is, but rename it to platform_get_irq_silent() to get rid of the expectation invoked by the naming similarity that motivated you to change platform_get_irq_optional(). Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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