Messages in this thread | | | Date | Thu, 12 Dec 2013 15:38:42 +0100 | Subject | Re: [PATCH 2/3] pinctrl: at91: initialize config parameter to 0 | From | Linus Walleij <> |
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On Mon, Dec 9, 2013 at 9:24 AM, Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
>> - dev_dbg(info->dev, "%s:%d, pin_id=%d, config=0x%lx", __func__, >> __LINE__, pin_id, *config); >> + *config = 0; >> + dev_dbg(info->dev, "%s:%d, pin_id=%d", __func__, __LINE__, >> pin_id); >> pio = pin_to_controller(info, pin_to_bank(pin_id)); >> pin = pin_id % MAX_NB_GPIO_PER_BANK; > > > Beyond this patch, I must say that I am puzzled by this function. > > What I read from the prototype documentation and what I see in different > implementations is different...
Yeah, we need to fix this mess.
> Linus, can we have a review of this function because it seems not in line > with what is used for u300 (but on the other hand looks like the what is > returned by pinctrl-exynos5440.c driver for example).
It is supposed to read out one config at the time, if and only if used with the generic pin config.
Typically:
enum pin_config_param param = (enum pin_config_param) *config;
switch (param) { case PIN_CONFIG_BIAS_HIGH_IMPEDANCE: *config = 0; if (biasmode) return 0; else return -EINVAL; break; (...)
return -ENOTSUPP;
However AT91 is *not* using generic pin config, so the semantics of this call is driver-dependent. In your case the implementation get all the configs at once, which is an efficient shortcut if you don't need to be general and enumerat all possible configs.
> What would be the consequences if we change this function's behavior: I mean > use of -EINVAL for pin configuration "available but disabled" as said in > include/linux/pinctrl/pinconf.h?
That code will propagate back ... I guess you'd have to test it :-/
Yours, Linus Walleij
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