pinctrl: pinctrl-single: Fix pcs_request_gpio() when bits_per_mux != 0

This fixes pcs_request_gpio() in the pinctrl-single driver when
bits_per_mux != 0. It appears this was overlooked when the multiple
pins per register feature was added.

Fixes: 4e7e8017 ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules")
Signed-off-by: David Lechner <david@lechnology.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-single.c

@@ -391,9 +391,25 @@ 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 byte_num, offset, pin_shift;
+
+			byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
+			offset = (byte_num / mux_bytes) * mux_bytes;
+			pin_shift = pin % (pcs->width / pcs->bits_per_pin) *
+				    pcs->bits_per_pin;
+
+			data = pcs->read(pcs->base + offset);
+			data &= ~(pcs->fmask << pin_shift);
+			data |= frange->gpiofunc << pin_shift;
+			pcs->write(data, pcs->base + offset);
+		} else {
+			data = pcs->read(pcs->base + pin * mux_bytes);
+			data &= ~pcs->fmask;
+			data |= frange->gpiofunc;
+			pcs->write(data, pcs->base + pin * mux_bytes);
+		}
 		break;
 	}
 	return 0;