pinctrl: renesas: Add I/O voltage level flag

This patch adds config macros describing the voltage levels available on
a pin. The current default (3.3V/1.8V) maps to zero to avoid having to
change existing PFC implementations.
Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210112165912.30876-3-uli+renesas@fpond.euSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/pinctrl/renesas/pinctrl.c

@@ -634,6 +634,9 @@ static int sh_pfc_pinconf_get(struct pinctrl_dev *pctldev, unsigned _pin,
 	}
 
 	case PIN_CONFIG_POWER_SOURCE: {
+		int idx = sh_pfc_get_pin_index(pfc, _pin);
+		const struct sh_pfc_pin *pin = &pfc->info->pins[idx];
+		unsigned int lower_voltage;
 		u32 pocctrl, val;
 		int bit;
 
@@ -648,7 +651,10 @@ static int sh_pfc_pinconf_get(struct pinctrl_dev *pctldev, unsigned _pin,
 		val = sh_pfc_read(pfc, pocctrl);
 		spin_unlock_irqrestore(&pfc->lock, flags);
 
-		arg = (val & BIT(bit)) ? 3300 : 1800;
+		lower_voltage = (pin->configs & SH_PFC_PIN_VOLTAGE_25_33) ?
+			2500 : 1800;
+
+		arg = (val & BIT(bit)) ? 3300 : lower_voltage;
 		break;
 	}
 
@@ -702,6 +708,9 @@ static int sh_pfc_pinconf_set(struct pinctrl_dev *pctldev, unsigned _pin,
 
 		case PIN_CONFIG_POWER_SOURCE: {
 			unsigned int mV = pinconf_to_config_argument(configs[i]);
+			int idx = sh_pfc_get_pin_index(pfc, _pin);
+			const struct sh_pfc_pin *pin = &pfc->info->pins[idx];
+			unsigned int lower_voltage;
 			u32 pocctrl, val;
 			int bit;
 
@@ -712,7 +721,10 @@ static int sh_pfc_pinconf_set(struct pinctrl_dev *pctldev, unsigned _pin,
 			if (WARN(bit < 0, "invalid pin %#x", _pin))
 				return bit;
 
-			if (mV != 1800 && mV != 3300)
+			lower_voltage = (pin->configs & SH_PFC_PIN_VOLTAGE_25_33) ?
+				2500 : 1800;
+
+			if (mV != lower_voltage && mV != 3300)
 				return -EINVAL;
 
 			spin_lock_irqsave(&pfc->lock, flags);

drivers/pinctrl/renesas/sh_pfc.h

@@ -31,6 +31,15 @@ enum {
 					 SH_PFC_PIN_CFG_PULL_DOWN)
 #define SH_PFC_PIN_CFG_IO_VOLTAGE	(1 << 4)
 #define SH_PFC_PIN_CFG_DRIVE_STRENGTH	(1 << 5)
+
+#define SH_PFC_PIN_VOLTAGE_18_33	(0 << 6)
+#define SH_PFC_PIN_VOLTAGE_25_33	(1 << 6)
+
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_18_33	(SH_PFC_PIN_CFG_IO_VOLTAGE | \
+					 SH_PFC_PIN_VOLTAGE_18_33)
+#define SH_PFC_PIN_CFG_IO_VOLTAGE_25_33	(SH_PFC_PIN_CFG_IO_VOLTAGE | \
+					 SH_PFC_PIN_VOLTAGE_25_33)
+
 #define SH_PFC_PIN_CFG_NO_GPIO		(1 << 31)
 
 struct sh_pfc_pin {