pinctrl: sh-pfc: r8a7791: 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-r8a7791.c

@@ -13,6 +13,10 @@
 
 #include "sh_pfc.h"
 
+/*
+ * Pins 0-23 assigned to GPIO bank 6 can be used for SD interfaces in
+ * which case they support both 3.3V and 1.8V signalling.
+ */
 #define CPU_ALL_PORT(fn, sfx)						\
 	PORT_GP_32(0, fn, sfx),						\
 	PORT_GP_26(1, fn, sfx),						\
@@ -20,7 +24,15 @@
 	PORT_GP_32(3, fn, sfx),						\
 	PORT_GP_32(4, fn, sfx),						\
 	PORT_GP_32(5, fn, sfx),						\
-	PORT_GP_32(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),					\
+	PORT_GP_1(6, 26, fn, sfx),					\
+	PORT_GP_1(6, 27, fn, sfx),					\
+	PORT_GP_1(6, 28, fn, sfx),					\
+	PORT_GP_1(6, 29, fn, sfx),					\
+	PORT_GP_1(6, 30, fn, sfx),					\
+	PORT_GP_1(6, 31, fn, sfx),					\
 	PORT_GP_26(7, fn, sfx)
 
 enum {
@@ -6404,9 +6416,24 @@ static const struct pinmux_cfg_reg pinmux_config_regs[] = {
 	{ },
 };
 
+static int r8a7791_pin_to_pocctrl(struct sh_pfc *pfc, unsigned int pin, u32 *pocctrl)
+{
+	if (pin < RCAR_GP_PIN(6, 0) || pin > RCAR_GP_PIN(6, 23))
+		return -EINVAL;
+
+	*pocctrl = 0xe606008c;
+
+	return 31 - (pin & 0x1f);
+}
+
+static const struct sh_pfc_soc_operations r8a7791_pinmux_ops = {
+	.pin_to_pocctrl = r8a7791_pin_to_pocctrl,
+};
+
 #ifdef CONFIG_PINCTRL_PFC_R8A7791
 const struct sh_pfc_soc_info r8a7791_pinmux_info = {
 	.name = "r8a77910_pfc",
+	.ops = &r8a7791_pinmux_ops,
 	.unlock_reg = 0xe6060000, /* PMMR */
 
 	.function = { PINMUX_FUNCTION_BEGIN, PINMUX_FUNCTION_END },