pinctrl: renesas: rcar: Avoid changing PUDn when disabling bias

When disabling pin bias, there is no need to touch the LSI pin
pull-up/down control register (PUDn), which selects between pull-up and
pull-down.  Just disabling the pull-up/down function through the LSI pin
pull-enable register (PUENn) is sufficient.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/071ec644de2555da593a4531ef5d3e4d79cf997d.1625064076.git.geert+renesas@glider.be

drivers/pinctrl/renesas/pinctrl.c

@@ -898,17 +898,17 @@ void rcar_pinmux_set_bias(struct sh_pfc *pfc, unsigned int pin,
 
 	if (reg->puen) {
 		enable = sh_pfc_read(pfc, reg->puen) & ~BIT(bit);
-		if (bias != PIN_CONFIG_BIAS_DISABLE)
+		if (bias != PIN_CONFIG_BIAS_DISABLE) {
 			enable |= BIT(bit);
 
-		if (reg->pud) {
-			updown = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);
-			if (bias == PIN_CONFIG_BIAS_PULL_UP)
-				updown |= BIT(bit);
+			if (reg->pud) {
+				updown = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);
+				if (bias == PIN_CONFIG_BIAS_PULL_UP)
+					updown |= BIT(bit);
 
-			sh_pfc_write(pfc, reg->pud, updown);
+				sh_pfc_write(pfc, reg->pud, updown);
+			}
 		}
-
 		sh_pfc_write(pfc, reg->puen, enable);
 	} else {
 		enable = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);