Re: [PATCH v2] pinctrl: single: support GPIO for bits pinctrl

[Tony Lindgren <tony@atomide.com>]

* Jun Nie <jun.nie@linaro.org> [150706 06:59]:
> Support GPIO for one register control multiple pins case
> with calculating register offset first, then bit offset.
> 
> Signed-off-by: Jun Nie <jun.nie@linaro.org>
> ---
>  drivers/pinctrl/pinctrl-single.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
> index 13b45f2..4f23ef0 100644
> --- a/drivers/pinctrl/pinctrl-single.c
> +++ b/drivers/pinctrl/pinctrl-single.c
> @@ -494,7 +494,7 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>  	struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
>  	struct pcs_gpiofunc_range *frange = NULL;
>  	struct list_head *pos, *tmp;
> -	int mux_bytes = 0;
> +	int offset, mux_bytes = 0;
>  	unsigned data;
>  
>  	/* If function mask is null, return directly. */
> @@ -507,9 +507,23 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>  			|| pin < frange->offset)
>  			continue;
>  		mux_bytes = pcs->width / BITS_PER_BYTE;
> -		data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
> -		data |= frange->gpiofunc;
> -		pcs->write(data, pcs->base + pin * mux_bytes);
> +		if (pcs->bits_per_mux) {
> +			int pin_pos, byte_num, num_pins_in_register;
> +
> +			num_pins_in_register = pcs->width / pcs->bits_per_pin;
> +			byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
> +			offset = (byte_num / mux_bytes) * mux_bytes;
> +			pin_pos = pin % num_pins_in_register;
> +			pin_pos *= pcs->bits_per_pin;
> +			data = pcs->read(pcs->base + offset) &
> +				~(pcs->fmask << pin_pos);
> +			data |= (frange->gpiofunc & pcs->fmask) << pin_pos;

I don't quite follow you here.. The pcs->fmask is for the whole register,
so I think the fmask should be checked the same way in this case also:
		
			data = pcs->read(pcs->base + offset) & ~pcs->fmask;
			...

I don't think we can safely assume the fmask would behave differently
in this case.

Regards,

Tony