pinctrl: sh-pfc: r8a7794: Implement voltage switching for SDHI

All the SHDIs can operate with either 3.3V or 1.8V signals, depending
on negotiation with the card.

Based on work by Wolfram Sang for the r8a7790.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/pinctrl/sh-pfc/pfc-r8a7794.c

@@ -22,7 +22,9 @@
 	PORT_GP_32(3, fn, sfx),						\
 	PORT_GP_32(4, fn, sfx),						\
 	PORT_GP_28(5, fn, sfx),						\
-	PORT_GP_26(6, fn, sfx)
+	PORT_GP_CFG_24(6, fn, sfx, SH_PFC_PIN_CFG_IO_VOLTAGE),		\
+	PORT_GP_1(6, 24, fn, sfx),					\
+	PORT_GP_1(6, 25, fn, sfx)
 
 enum {
 	PINMUX_RESERVED = 0,
@@ -5160,8 +5162,32 @@ static const struct pinmux_cfg_reg pinmux_config_regs[] = {
 	{ },
 };
 
+static int r8a7794_pin_to_pocctrl(struct sh_pfc *pfc, unsigned int pin, u32 *pocctrl)
+{
+	*pocctrl = 0xe606006c;
+
+	switch (pin & 0x1f) {
+	case 6: return 23;
+	case 7: return 16;
+	case 14: return 15;
+	case 15: return 8;
+	case 0 ... 5:
+	case 8 ... 13:
+		return 22 - (pin & 0x1f);
+	case 16 ... 23:
+		return 47 - (pin & 0x1f);
+	}
+
+	return -EINVAL;
+}
+
+static const struct sh_pfc_soc_operations r8a7794_pinmux_ops = {
+	.pin_to_pocctrl = r8a7794_pin_to_pocctrl,
+};
+
 const struct sh_pfc_soc_info r8a7794_pinmux_info = {
 	.name = "r8a77940_pfc",
+	.ops = &r8a7794_pinmux_ops,
 	.unlock_reg = 0xe6060000, /* PMMR */
 
 	.function = { PINMUX_FUNCTION_BEGIN, PINMUX_FUNCTION_END },