pinctrl: renesas: rzg2l: Add support to select power source for Ethernet pins

The GPIO controller available on RZ/G3S (but also on RZ/G2L) supports
setting the power source for Ethernet pins.  Based on the interface b/w
the Ethernet controller and the Ethernet PHY, and on board design, a
specific power source needs to be selected.  The GPIO controller
supports 1.8V, 2.5V, and 3.3V power source selection for the Ethernet
pins.  This can be selected though the ETHx_POC registers (x={0, 1}).

Adjust the driver to support this, and to do proper instantiation for
the RZ/G3S and RZ/G2L SoCs.  On RZ/G2L only the get operation has been
tested at the moment.

While at it, as the power registers on RZ/G2L support access sizes of 8
bits, and these registers on RZ/G3S support access sizes of 8/16/32
bits, replace writel()/readl() on these registers with writeb()/readb().
This should allow us to use the same code on both SoCs w/o any issues.

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/20231207070700.4156557-6-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: claudiubeznea

drivers/pinctrl/renesas/pinctrl-rzg2l.c

@@ -107,16 +107,17 @@
 #define IEN(off)		(0x1800 + (off) * 8)
 #define ISEL(off)		(0x2C00 + (off) * 8)
 #define SD_CH(off, ch)		((off) + (ch) * 4)
+#define ETH_POC(off, ch)	((off) + (ch) * 4)
 #define QSPI			(0x3008)
 
+#define PVDD_2500		2	/* I/O domain voltage 2.5V */
 #define PVDD_1800		1	/* I/O domain voltage <= 1.8V */
 #define PVDD_3300		0	/* I/O domain voltage >= 3.3V */
 
 #define PWPR_B0WI		BIT(7)	/* Bit Write Disable */
 #define PWPR_PFCWE		BIT(6)	/* PFC Register Write Enable */
 
 #define PM_MASK			0x03
-#define PVDD_MASK		0x01
 #define PFC_MASK		0x07
 #define IEN_MASK		0x01
 #define IOLH_MASK		0x03
@@ -135,10 +136,12 @@
  * struct rzg2l_register_offsets - specific register offsets
  * @pwpr: PWPR register offset
  * @sd_ch: SD_CH register offset
+ * @eth_poc: ETH_POC register offset
  */
 struct rzg2l_register_offsets {
 	u16 pwpr;
 	u16 sd_ch;
+	u16 eth_poc;
 };
 
 /**
@@ -604,6 +607,10 @@ static int rzg2l_caps_to_pwr_reg(const struct rzg2l_register_offsets *regs, u32
 		return SD_CH(regs->sd_ch, 0);
 	if (caps & PIN_CFG_IO_VMC_SD1)
 		return SD_CH(regs->sd_ch, 1);
+	if (caps & PIN_CFG_IO_VMC_ETH0)
+		return ETH_POC(regs->eth_poc, 0);
+	if (caps & PIN_CFG_IO_VMC_ETH1)
+		return ETH_POC(regs->eth_poc, 1);
 	if (caps & PIN_CFG_IO_VMC_QSPI)
 		return QSPI;
 
@@ -615,6 +622,7 @@ static int rzg2l_get_power_source(struct rzg2l_pinctrl *pctrl, u32 pin, u32 caps
 	const struct rzg2l_hwcfg *hwcfg = pctrl->data->hwcfg;
 	const struct rzg2l_register_offsets *regs = &hwcfg->regs;
 	int pwr_reg;
+	u8 val;
 
 	if (caps & PIN_CFG_SOFT_PS)
 		return pctrl->settings[pin].power_source;
@@ -623,25 +631,51 @@ static int rzg2l_get_power_source(struct rzg2l_pinctrl *pctrl, u32 pin, u32 caps
 	if (pwr_reg < 0)
 		return pwr_reg;
 
-	return (readl(pctrl->base + pwr_reg) & PVDD_MASK) ? 1800 : 3300;
+	val = readb(pctrl->base + pwr_reg);
+	switch (val) {
+	case PVDD_1800:
+		return 1800;
+	case PVDD_2500:
+		return 2500;
+	case PVDD_3300:
+		return 3300;
+	default:
+		/* Should not happen. */
+		return -EINVAL;
+	}
 }
 
 static int rzg2l_set_power_source(struct rzg2l_pinctrl *pctrl, u32 pin, u32 caps, u32 ps)
 {
 	const struct rzg2l_hwcfg *hwcfg = pctrl->data->hwcfg;
 	const struct rzg2l_register_offsets *regs = &hwcfg->regs;
 	int pwr_reg;
+	u8 val;
 
 	if (caps & PIN_CFG_SOFT_PS) {
 		pctrl->settings[pin].power_source = ps;
 		return 0;
 	}
 
+	switch (ps) {
+	case 1800:
+		val = PVDD_1800;
+		break;
+	case 2500:
+		val = PVDD_2500;
+		break;
+	case 3300:
+		val = PVDD_3300;
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	pwr_reg = rzg2l_caps_to_pwr_reg(regs, caps);
 	if (pwr_reg < 0)
 		return pwr_reg;
 
-	writel((ps == 1800) ? PVDD_1800 : PVDD_3300, pctrl->base + pwr_reg);
+	writeb(val, pctrl->base + pwr_reg);
 	pctrl->settings[pin].power_source = ps;
 
 	return 0;
@@ -1885,6 +1919,7 @@ static const struct rzg2l_hwcfg rzg2l_hwcfg = {
 	.regs = {
 		.pwpr = 0x3014,
 		.sd_ch = 0x3000,
+		.eth_poc = 0x300c,
 	},
 	.iolh_groupa_ua = {
 		/* 3v3 power source */
@@ -1897,6 +1932,7 @@ static const struct rzg2l_hwcfg rzg3s_hwcfg = {
 	.regs = {
 		.pwpr = 0x3000,
 		.sd_ch = 0x3004,
+		.eth_poc = 0x3010,
 	},
 	.iolh_groupa_ua = {
 		/* 1v8 power source */