drivers: pinctrl: pfc_rcar: add support of voltage control to pfc driver

Add support of voltage control to Renesas PFC driver. Voltage register
mappings have been added to r8a77951 and r8a77961 SoCs.

Allow 'power-source' property for 'renesas,rcar-pfc' node. This property
will be used for configuring IO voltage on appropriate pin. For now it
is possible to have only two voltages: 1.8 and 3.3.

Note: it is possible to change voltage only for SD/MMC pins on r8a77951
      and r8a77961 SoCs.

Signed-off-by: Mykola Kvach <mykola_kvach@epam.com>

drivers/pinctrl/Kconfig.rcar

@@ -7,3 +7,8 @@ config PINCTRL_RCAR_PFC
 	depends on DT_HAS_RENESAS_RCAR_PFC_ENABLED
 	help
 	  Enable pin controller driver for Renesas RCar SoC
+
+config PINCTRL_RCAR_VOLTAGE_CONTROL
+	bool "Voltage control functionality of Renesas R-Car PFC driver"
+	default y if SOC_SERIES_RCAR_GEN3
+	depends on PINCTRL_RCAR_PFC

drivers/pinctrl/pfc_rcar.c

@@ -35,6 +35,14 @@ static const uintptr_t reg_base[] = {
 #error Unsupported SoC Series
 #endif
 
+#ifdef CONFIG_PINCTRL_RCAR_VOLTAGE_CONTROL
+/* POC Control Register can control IO voltage level that is supplied to the pin */
+struct pfc_pocctrl_reg {
+	uint32_t offset;
+	const uint16_t pins[32];
+};
+#endif /* CONFIG_PINCTRL_RCAR_VOLTAGE_CONTROL */
+
 /*
  * Each drive step is either encoded in 2 or 3 bits.
  * So based on a 24 mA maximum value each step is either
@@ -189,6 +197,110 @@ int pfc_rcar_set_bias(uintptr_t pfc_base, uint16_t pin, uint16_t flags)
 	return 0;
 }
 
+#ifdef CONFIG_PINCTRL_RCAR_VOLTAGE_CONTROL
+
+const struct pfc_pocctrl_reg pfc_r8a77951_r8a77961_volt_regs[] = {
+	{
+		.offset = 0x0380,
+		.pins = {
+			[0]  = RCAR_GP_PIN(3,  0),    /* SD0_CLK  */
+			[1]  = RCAR_GP_PIN(3,  1),    /* SD0_CMD  */
+			[2]  = RCAR_GP_PIN(3,  2),    /* SD0_DAT0 */
+			[3]  = RCAR_GP_PIN(3,  3),    /* SD0_DAT1 */
+			[4]  = RCAR_GP_PIN(3,  4),    /* SD0_DAT2 */
+			[5]  = RCAR_GP_PIN(3,  5),    /* SD0_DAT3 */
+			[6]  = RCAR_GP_PIN(3,  6),    /* SD1_CLK  */
+			[7]  = RCAR_GP_PIN(3,  7),    /* SD1_CMD  */
+			[8]  = RCAR_GP_PIN(3,  8),    /* SD1_DAT0 */
+			[9]  = RCAR_GP_PIN(3,  9),    /* SD1_DAT1 */
+			[10] = RCAR_GP_PIN(3,  10),   /* SD1_DAT2 */
+			[11] = RCAR_GP_PIN(3,  11),   /* SD1_DAT3 */
+			[12] = RCAR_GP_PIN(4,  0),    /* SD2_CLK  */
+			[13] = RCAR_GP_PIN(4,  1),    /* SD2_CMD  */
+			[14] = RCAR_GP_PIN(4,  2),    /* SD2_DAT0 */
+			[15] = RCAR_GP_PIN(4,  3),    /* SD2_DAT1 */
+			[16] = RCAR_GP_PIN(4,  4),    /* SD2_DAT2 */
+			[17] = RCAR_GP_PIN(4,  5),    /* SD2_DAT3 */
+			[18] = RCAR_GP_PIN(4,  6),    /* SD2_DS   */
+			[19] = RCAR_GP_PIN(4,  7),    /* SD3_CLK  */
+			[20] = RCAR_GP_PIN(4,  8),    /* SD3_CMD  */
+			[21] = RCAR_GP_PIN(4,  9),    /* SD3_DAT0 */
+			[22] = RCAR_GP_PIN(4,  10),   /* SD3_DAT1 */
+			[23] = RCAR_GP_PIN(4,  11),   /* SD3_DAT2 */
+			[24] = RCAR_GP_PIN(4,  12),   /* SD3_DAT3 */
+			[25] = RCAR_GP_PIN(4,  13),   /* SD3_DAT4 */
+			[26] = RCAR_GP_PIN(4,  14),   /* SD3_DAT5 */
+			[27] = RCAR_GP_PIN(4,  15),   /* SD3_DAT6 */
+			[28] = RCAR_GP_PIN(4,  16),   /* SD3_DAT7 */
+			[29] = RCAR_GP_PIN(4,  17),   /* SD3_DS   */
+			[30] = -1,
+			[31] = -1,
+		}
+	},
+	{ /* sentinel */ },
+};
+
+static const struct pfc_pocctrl_reg *pfc_rcar_get_io_voltage_regs(void)
+{
+	return pfc_r8a77951_r8a77961_volt_regs;
+}
+
+static const struct pfc_pocctrl_reg *pfc_rcar_get_pocctrl_reg(uint16_t pin, uint8_t *bit)
+{
+	const struct pfc_pocctrl_reg *voltage_regs = pfc_rcar_get_io_voltage_regs();
+
+	BUILD_ASSERT(ARRAY_SIZE(voltage_regs->pins) < UINT8_MAX);
+
+	/* Loop around all the registers to find the bit for a given pin */
+	while (voltage_regs && voltage_regs->offset) {
+		uint8_t i;
+
+		for (i = 0U; i < ARRAY_SIZE(voltage_regs->pins); i++) {
+			if (voltage_regs->pins[i] == pin) {
+				*bit = i;
+				return voltage_regs;
+			}
+		}
+		voltage_regs++;
+	}
+
+	return NULL;
+}
+
+static void pfc_rcar_set_voltage(uintptr_t pfc_base, uint16_t pin, uint16_t voltage)
+{
+	uint32_t val;
+	uint8_t bit;
+	const struct pfc_pocctrl_reg *voltage_reg;
+
+	voltage_reg = pfc_rcar_get_pocctrl_reg(pin, &bit);
+	if (!voltage_reg) {
+		return;
+	}
+
+	val = sys_read32(pfc_base + voltage_reg->offset);
+
+	switch (voltage) {
+	case PIN_VOLTAGE_1P8V:
+		if (!(val & BIT(bit))) {
+			return;
+		}
+		val &= ~BIT(bit);
+		break;
+	case PIN_VOLTAGE_3P3V:
+		if (val & BIT(bit)) {
+			return;
+		}
+		val |= BIT(bit);
+		break;
+	default:
+		break;
+	}
+
+	pfc_rcar_write(pfc_base, voltage_reg->offset, val);
+}
+#endif /* CONFIG_PINCTRL_RCAR_VOLTAGE_CONTROL */
+
 int pinctrl_configure_pin(const pinctrl_soc_pin_t *pin)
 {
 	int ret = 0;
@@ -214,6 +326,12 @@ int pinctrl_configure_pin(const pinctrl_soc_pin_t *pin)
 		return -EINVAL;
 	}
 
+#ifdef CONFIG_PINCTRL_RCAR_VOLTAGE_CONTROL
+	if (pin->voltage != PIN_VOLTAGE_NONE) {
+		pfc_rcar_set_voltage(pfc_base, pin->pin, pin->voltage);
+	}
+#endif
+
 	/* Select function for pin */
 	if ((pin->flags & RCAR_PIN_FLAGS_FUNC_SET) != 0U) {
 		pfc_rcar_set_ipsr(pfc_base, &pin->func);

dts/bindings/pinctrl/renesas,rcar-pfc.yaml

@@ -51,6 +51,7 @@ description: |
     - bias-pull-down
     - bias-pull-up
     - drive-strength
+    - power-source
 
     To link pin configurations with a device, use a pinctrl-N property for some
     number N, like this example you could place in your board's DTS file:
@@ -82,6 +83,7 @@ child-binding:
         - bias-pull-down
         - bias-pull-up
         - drive-strength
+        - power-source
 
   properties:
     pin:

include/zephyr/dt-bindings/pinctrl/renesas/pinctrl-rcar-common.h

@@ -72,4 +72,8 @@
 #define IP2SR5(shift, func) IPnSR(2, 5, shift, func)
 #define IP3SR5(shift, func) IPnSR(3, 5, shift, func)
 
+#define PIN_VOLTAGE_NONE 0
+#define PIN_VOLTAGE_1P8V 1
+#define PIN_VOLTAGE_3P3V 2
+
 #endif /* ZEPHYR_INCLUDE_DT_BINDINGS_PINCTRL_RENESAS_PINCTRL_RCAR_COMMON_H_ */

soc/arm/renesas_rcar/common/pinctrl_rcar.h

@@ -38,6 +38,7 @@ typedef struct pinctrl_soc_pin {
 	struct rcar_pin_func func;
 	uint8_t flags;
 	uint8_t drive_strength;
+	uint8_t voltage;
 } pinctrl_soc_pin_t;
 
 #define RCAR_IPSR(node_id) DT_PROP_BY_IDX(node_id, pin, 1)
@@ -66,6 +67,10 @@ typedef struct pinctrl_soc_pin {
 		.drive_strength =					       \
 			COND_CODE_1(DT_NODE_HAS_PROP(node_id, drive_strength), \
 				    (DT_PROP(node_id, drive_strength)), (0)),  \
+		.voltage = COND_CODE_1(DT_NODE_HAS_PROP(node_id,	       \
+							power_source),	       \
+				       (DT_PROP(node_id, power_source)),       \
+				       (PIN_VOLTAGE_NONE)),		       \
 	},
 
 /**

soc/arm64/renesas_rcar/gen3/pinctrl_soc.h

@@ -37,6 +37,7 @@ typedef struct pinctrl_soc_pin {
 	struct rcar_pin_func func;
 	uint8_t flags;
 	uint8_t drive_strength;
+	uint8_t voltage;
 } pinctrl_soc_pin_t;
 
 #define RCAR_IPSR(node_id) DT_PROP_BY_IDX(node_id, pin, 1)
@@ -65,6 +66,10 @@ typedef struct pinctrl_soc_pin {
 		.drive_strength =					       \
 			COND_CODE_1(DT_NODE_HAS_PROP(node_id, drive_strength), \
 				    (DT_PROP(node_id, drive_strength)), (0)),  \
+		.voltage = COND_CODE_1(DT_NODE_HAS_PROP(node_id,	       \
+							power_source),	       \
+				       (DT_PROP(node_id, power_source)),       \
+				       (PIN_VOLTAGE_NONE)),		       \
 	},
 
 /**