* Keerthy <j-keerthy@xxxxxx> [160413 00:03]:
> pcs_parse_bits_in_pinctrl_entry uses ffs which gives bit indices
> ranging from 1 to MAX. This leads to a corner case where we try to request
> the pin number = MAX and fails.
>
> bit_pos value is being calculted using ffs. pin_num_from_lsb uses
> bit_pos value. pins array is populated with:
>
> pin + pin_num_from_lsb.
>
> The above is 1 more than usual bit indices as bit_pos uses ffs to compute
> first set bit. Hence the last of the pins array is populated with the MAX
> value and not MAX - 1 which causes error when we call pin_request.
Hmm that sounds like a bug to me, just one comment below.
> --- a/drivers/pinctrl/pinctrl-single.c
> +++ b/drivers/pinctrl/pinctrl-single.c
> @@ -1323,9 +1323,9 @@ static int pcs_parse_bits_in_pinctrl_entry(struct pcs_device *pcs,
>
> /* Parse pins in each row from LSB */
> while (mask) {
> - bit_pos = ffs(mask);
> + bit_pos = __ffs(mask);
> pin_num_from_lsb = bit_pos / pcs->bits_per_pin;
> - mask_pos = ((pcs->fmask) << (bit_pos - 1));
> + mask_pos = ((pcs->fmask) << bit_pos);
> val_pos = val & mask_pos;
> submask = mask & mask_pos;
Can you please also change the pcs->fshift = ffs(pcs->fmask) - 1 to
use __ffs to avoid confusion?
Regards,
Tony
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