Messages in this thread | | | Subject | Re: [PATCH 1/2] gpio-ich: Check for pin availability at request time | From | Peter Tyser <> | Date | Tue, 05 Mar 2013 12:16:54 -0600 |
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Hi Jean,
On Tue, 2013-03-05 at 09:06 +0100, Jean Delvare wrote: > Stop checking for pin availability in get functions. These functions > can be called repeatedly, so checking every time is bad for > performance. > > Instead, check at pin request time. This only happens once, and we can > let the caller know of the unavailability much earlier.
Is there a reason to not remove the ichx_gpio_check_available() calls from the ichx_gpio_direction_output() and ichx_gpio_direction_input() functions in this change?
I had originally assumed these checks were to support the "legacy" interface where users could use the GPIOs without first requesting the GPIO, but after looking a bit further it looks like the gpiolib code to set a GPIO as an input or output does auto-request the GPIO before setting its direction. So I'd assume your 1 check in ichx_gpio_request() would cover the "legacy" interface too.
Best, Peter
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