pfc: rmobile: Add hook to configure pin as GPIO

Add hook into the PFC driver to allow the GPIO driver to toggle
GPSR registers into GPIO mode when GPIO is requested.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

drivers/pinctrl/renesas/pfc.c

@@ -448,6 +448,35 @@ static const char *sh_pfc_pinctrl_get_function_name(struct udevice *dev,
 	return priv->pfc.info->functions[selector].name;
 }
 
+int sh_pfc_config_mux_for_gpio(struct udevice *dev, unsigned pin_selector)
+{
+	struct sh_pfc_pinctrl_priv *priv = dev_get_priv(dev);
+	struct sh_pfc_pinctrl *pmx = &priv->pmx;
+	struct sh_pfc *pfc = &priv->pfc;
+	struct sh_pfc_pin_config *cfg;
+	const struct sh_pfc_pin *pin = NULL;
+	int i, idx;
+
+	for (i = 1; i < pfc->info->nr_pins; i++) {
+		if (priv->pfc.info->pins[i].pin != pin_selector)
+			continue;
+
+		pin = &priv->pfc.info->pins[i];
+		break;
+	}
+
+	if (!pin)
+		return -EINVAL;
+
+	idx = sh_pfc_get_pin_index(pfc, pin->pin);
+	cfg = &pmx->configs[idx];
+
+	if (cfg->type != PINMUX_TYPE_NONE)
+		return -EBUSY;
+
+	return sh_pfc_config_mux(pfc, pin->enum_id, PINMUX_TYPE_GPIO);
+}
+
 static int sh_pfc_pinctrl_pin_set(struct udevice *dev, unsigned pin_selector,
 				  unsigned func_selector)
 {

drivers/pinctrl/renesas/sh_pfc.h

@@ -243,6 +243,7 @@ void sh_pfc_write_reg(struct sh_pfc *pfc, u32 reg, unsigned int width, u32 data)
 const struct sh_pfc_bias_info *
 sh_pfc_pin_to_bias_info(const struct sh_pfc_bias_info *info,
 			unsigned int num, unsigned int pin);
+int sh_pfc_config_mux_for_gpio(struct udevice *dev, unsigned pin_selector);
 
 extern const struct sh_pfc_soc_info r8a7795_pinmux_info;
 extern const struct sh_pfc_soc_info r8a7796_pinmux_info;