Re: [STLinux Kernel] [PATCH 2/6] pinctrl: st: Introduce a 'get pin function' call

[Maxime Coquelin <maxime.coquelin@st.com>]

On 03/18/2015 11:51 AM, Lee Jones wrote:
> This call fetches the numerical function value a specified pin is
> currently operating in.  Function zero is more often than not the
> GPIO function.  Greater than zero values represent an alternative
> function.  You'd need to either look those up in the Device Tree
> sources or the Programmer's Manual.
>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
>   drivers/pinctrl/pinctrl-st.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
>
> diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
> index 9e5ec00..5362e45 100644
> --- a/drivers/pinctrl/pinctrl-st.c
> +++ b/drivers/pinctrl/pinctrl-st.c
> @@ -460,6 +460,20 @@ static void st_pctl_set_function(struct st_pio_control *pc,
>   	regmap_field_write(alt, val);
>   }
>   
> +static unsigned int st_pctl_get_pin_function(struct st_pio_control *pc, int pin)
> +{
> +	struct regmap_field *alt = pc->alt;
> +	unsigned int val;
> +	int offset = pin * 4;
> +
> +	if (!alt)
> +		return 0;
Shouldn't we print something if alt is NULL?
Else we can think we are on alternate 0.

> +
> +	regmap_field_read(alt, &val);
> +
> +	return (val >> offset) & 0xf;
> +}
> +
>   static unsigned long st_pinconf_delay_to_bit(unsigned int delay,
>   	const struct st_pctl_data *data, unsigned long config)
>   {