pinctrl: renesas: rzg2l: Add output enable support

Some of the Ethernet pins on RZ/G3S (but also valid for RZ/G2L) need to
have the direction of the IO buffer set as output for Ethernet to work
properly.  On RZ/G3S, these pins are P1_0/P7_0, P1_1/P7_1, and can have
the following Ethernet functions: TXC/TX_CLK or TX_CTL/TX_EN.

As the pins supporting output enable are SoC specific, and there is a
limited number of these pins (TXC/TX_CLK and/or TX_CTL/TX_EN), specify
output enable capable port limits in the platform-based configuration
data structure, to ensure proper validation.

The OEN support has been intantiated for RZ/G3S at the moment.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231207070700.4156557-7-claudiu.beznea.uj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/pinctrl/renesas/pinctrl-rzg2l.c

@@ -57,6 +57,7 @@
 #define PIN_CFG_FILCLKSEL		BIT(12)
 #define PIN_CFG_IOLH_C			BIT(13)
 #define PIN_CFG_SOFT_PS			BIT(14)
+#define PIN_CFG_OEN			BIT(15)
 
 #define RZG2L_MPXED_COMMON_PIN_FUNCS(group) \
 					(PIN_CFG_IOLH_##group | \
@@ -109,6 +110,7 @@
 #define SD_CH(off, ch)		((off) + (ch) * 4)
 #define ETH_POC(off, ch)	((off) + (ch) * 4)
 #define QSPI			(0x3008)
+#define ETH_MODE		(0x3018)
 
 #define PVDD_2500		2	/* I/O domain voltage 2.5V */
 #define PVDD_1800		1	/* I/O domain voltage <= 1.8V */
@@ -170,6 +172,8 @@ enum rzg2l_iolh_index {
  * @iolh_groupb_oi: IOLH group B output impedance specific values
  * @drive_strength_ua: drive strength in uA is supported (otherwise mA is supported)
  * @func_base: base number for port function (see register PFC)
+ * @oen_max_pin: the maximum pin number supporting output enable
+ * @oen_max_port: the maximum port number supporting output enable
  */
 struct rzg2l_hwcfg {
 	const struct rzg2l_register_offsets regs;
@@ -179,6 +183,8 @@ struct rzg2l_hwcfg {
 	u16 iolh_groupb_oi[4];
 	bool drive_strength_ua;
 	u8 func_base;
+	u8 oen_max_pin;
+	u8 oen_max_port;
 };
 
 struct rzg2l_dedicated_configs {
@@ -782,6 +788,66 @@ static bool rzg2l_ds_is_supported(struct rzg2l_pinctrl *pctrl, u32 caps,
 	return false;
 }
 
+static bool rzg2l_oen_is_supported(u32 caps, u8 pin, u8 max_pin)
+{
+	if (!(caps & PIN_CFG_OEN))
+		return false;
+
+	if (pin > max_pin)
+		return false;
+
+	return true;
+}
+
+static u8 rzg2l_pin_to_oen_bit(u32 offset, u8 pin, u8 max_port)
+{
+	if (pin)
+		pin *= 2;
+
+	if (offset / RZG2L_PINS_PER_PORT == max_port)
+		pin += 1;
+
+	return pin;
+}
+
+static u32 rzg2l_read_oen(struct rzg2l_pinctrl *pctrl, u32 caps, u32 offset, u8 pin)
+{
+	u8 max_port = pctrl->data->hwcfg->oen_max_port;
+	u8 max_pin = pctrl->data->hwcfg->oen_max_pin;
+	u8 bit;
+
+	if (!rzg2l_oen_is_supported(caps, pin, max_pin))
+		return 0;
+
+	bit = rzg2l_pin_to_oen_bit(offset, pin, max_port);
+
+	return !(readb(pctrl->base + ETH_MODE) & BIT(bit));
+}
+
+static int rzg2l_write_oen(struct rzg2l_pinctrl *pctrl, u32 caps, u32 offset, u8 pin, u8 oen)
+{
+	u8 max_port = pctrl->data->hwcfg->oen_max_port;
+	u8 max_pin = pctrl->data->hwcfg->oen_max_pin;
+	unsigned long flags;
+	u8 val, bit;
+
+	if (!rzg2l_oen_is_supported(caps, pin, max_pin))
+		return -EINVAL;
+
+	bit = rzg2l_pin_to_oen_bit(offset, pin, max_port);
+
+	spin_lock_irqsave(&pctrl->lock, flags);
+	val = readb(pctrl->base + ETH_MODE);
+	if (oen)
+		val &= ~BIT(bit);
+	else
+		val |= BIT(bit);
+	writeb(val, pctrl->base + ETH_MODE);
+	spin_unlock_irqrestore(&pctrl->lock, flags);
+
+	return 0;
+}
+
 static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
 				     unsigned int _pin,
 				     unsigned long *config)
@@ -819,6 +885,12 @@ static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
 			return -EINVAL;
 		break;
 
+	case PIN_CONFIG_OUTPUT_ENABLE:
+		arg = rzg2l_read_oen(pctrl, cfg, _pin, bit);
+		if (!arg)
+			return -EINVAL;
+		break;
+
 	case PIN_CONFIG_POWER_SOURCE:
 		ret = rzg2l_get_power_source(pctrl, _pin, cfg);
 		if (ret < 0)
@@ -920,6 +992,13 @@ static int rzg2l_pinctrl_pinconf_set(struct pinctrl_dev *pctldev,
 			rzg2l_rmw_pin_config(pctrl, IEN(off), bit, IEN_MASK, !!arg);
 			break;
 
+		case PIN_CONFIG_OUTPUT_ENABLE:
+			arg = pinconf_to_config_argument(_configs[i]);
+			ret = rzg2l_write_oen(pctrl, cfg, _pin, bit, !!arg);
+			if (ret)
+				return ret;
+			break;
+
 		case PIN_CONFIG_POWER_SOURCE:
 			settings.power_source = pinconf_to_config_argument(_configs[i]);
 			break;
@@ -1364,7 +1443,8 @@ static const u32 r9a07g043_gpio_configs[] = {
 static const u32 r9a08g045_gpio_configs[] = {
 	RZG2L_GPIO_PORT_PACK(4, 0x20, RZG3S_MPXED_PIN_FUNCS(A)),			/* P0  */
 	RZG2L_GPIO_PORT_PACK(5, 0x30, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
-								PIN_CFG_IO_VMC_ETH0)),	/* P1 */
+								PIN_CFG_IO_VMC_ETH0)) |
+				      PIN_CFG_OEN,					/* P1 */
 	RZG2L_GPIO_PORT_PACK(4, 0x31, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
 								PIN_CFG_IO_VMC_ETH0)),	/* P2 */
 	RZG2L_GPIO_PORT_PACK(4, 0x32, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
@@ -1374,7 +1454,8 @@ static const u32 r9a08g045_gpio_configs[] = {
 	RZG2L_GPIO_PORT_PACK(5, 0x21, RZG3S_MPXED_PIN_FUNCS(A)),			/* P5  */
 	RZG2L_GPIO_PORT_PACK(5, 0x22, RZG3S_MPXED_PIN_FUNCS(A)),			/* P6  */
 	RZG2L_GPIO_PORT_PACK(5, 0x34, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
-								PIN_CFG_IO_VMC_ETH1)),	/* P7 */
+								PIN_CFG_IO_VMC_ETH1)) |
+				      PIN_CFG_OEN,					/* P7 */
 	RZG2L_GPIO_PORT_PACK(5, 0x35, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
 								PIN_CFG_IO_VMC_ETH1)),	/* P8 */
 	RZG2L_GPIO_PORT_PACK(4, 0x36, RZG2L_MPXED_ETH_PIN_FUNCS(PIN_CFG_IOLH_C |
@@ -1956,6 +2037,8 @@ static const struct rzg2l_hwcfg rzg3s_hwcfg = {
 	},
 	.drive_strength_ua = true,
 	.func_base = 1,
+	.oen_max_pin = 1, /* Pin 1 of P0 and P7 is the maximum OEN pin. */
+	.oen_max_port = 7, /* P7_1 is the maximum OEN port. */
 };
 
 static struct rzg2l_pinctrl_data r9a07g043_data = {