[PATCH v4 1/2] pinctrl: renesas: Make sure the pin type is updated after setting the MUX

[Lad Prabhakar]

By default on startup all the pin types are configured to
PINMUX_TYPE_NONE (in sh_pfc_map_pins()), when pin is set as GPIO the
pin type is updated to PINMUX_TYPE_GPIO. But the type is not updated
when the pin is set as a function in sh_pfc_pinctrl_pin_set() or
sh_pfc_pinctrl_group_set() calls (these calls only set the MUX if
the pin type is PINMUX_TYPE_NONE ie unused).

So with the current implementation pin functionality could be overwritten
silently, for example if the same pin is added for SPI and serial.

This patch makes sure of updating pin type after every successful call to
sh_pfc_config_mux() and thus fixing from pin functionality to be
overwritten. Also a warning message is printed if the current pin is being
overwritten before abort.

This also avoids pin re-muxing to same type that is for example from
command line device is asked to re-probe/select (mmc dev x) we return
early with success in this case as the pin is already muxed.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz at bp.renesas.com>
---
 drivers/pinctrl/renesas/pfc.c | 52 +++++++++++++++++++++++++++++++----
 1 file changed, 47 insertions(+), 5 deletions(-)

diff --git a/drivers/pinctrl/renesas/pfc.c b/drivers/pinctrl/renesas/pfc.c
index 6cccd33c40..1b1f583ee6 100644
--- a/drivers/pinctrl/renesas/pfc.c
+++ b/drivers/pinctrl/renesas/pfc.c
@@ -45,6 +45,7 @@ enum sh_pfc_model {
 
 struct sh_pfc_pin_config {
 	u32 type;
+	const char *name;
 };
 
 struct sh_pfc_pinctrl {
@@ -488,14 +489,21 @@ static int sh_pfc_gpio_request_enable(struct udevice *dev,
 	idx = sh_pfc_get_pin_index(pfc, pin->pin);
 	cfg = &pmx->configs[idx];
 
-	if (cfg->type != PINMUX_TYPE_NONE)
+	if (cfg->type != PINMUX_TYPE_NONE) {
+		if (!strcmp(cfg->name, pin->name))
+			return 0;
+
+		dev_err(pfc->dev, "Pin already used as %s\n",
+			cfg->name);
 		return -EBUSY;
+	}
 
 	ret = sh_pfc_config_mux(pfc, pin->enum_id, PINMUX_TYPE_GPIO);
 	if (ret)
 		return ret;
 
 	cfg->type = PINMUX_TYPE_GPIO;
+	cfg->name = "gpio";
 
 	return 0;
 }
@@ -525,6 +533,7 @@ static int sh_pfc_gpio_disable_free(struct udevice *dev,
 	cfg = &pmx->configs[idx];
 
 	cfg->type = PINMUX_TYPE_NONE;
+	cfg->name = "none";
 
 	return 0;
 }
@@ -538,11 +547,25 @@ static int sh_pfc_pinctrl_pin_set(struct udevice *dev, unsigned pin_selector,
 	const struct sh_pfc_pin *pin = &priv->pfc.info->pins[pin_selector];
 	int idx = sh_pfc_get_pin_index(pfc, pin->pin);
 	struct sh_pfc_pin_config *cfg = &pmx->configs[idx];
+	int ret;
 
-	if (cfg->type != PINMUX_TYPE_NONE)
+	if (cfg->type != PINMUX_TYPE_NONE) {
+		if (!strcmp(cfg->name, pin->name))
+			return 0;
+
+		dev_err(pfc->dev, "Pin already used as %s\n",
+			cfg->name);
 		return -EBUSY;
+	}
+
+	ret = sh_pfc_config_mux(pfc, pin->enum_id, PINMUX_TYPE_FUNCTION);
+	if (ret)
+		return ret;
 
-	return sh_pfc_config_mux(pfc, pin->enum_id, PINMUX_TYPE_FUNCTION);
+	cfg->type = PINMUX_TYPE_FUNCTION;
+	cfg->name = "function";
+
+	return 0;
 }
 
 static int sh_pfc_pinctrl_group_set(struct udevice *dev, unsigned group_selector,
@@ -552,23 +575,41 @@ static int sh_pfc_pinctrl_group_set(struct udevice *dev, unsigned group_selector
 	struct sh_pfc_pinctrl *pmx = &priv->pmx;
 	struct sh_pfc *pfc = &priv->pfc;
 	const struct sh_pfc_pin_group *grp = &priv->pfc.info->groups[group_selector];
+	bool grp_pins_configured = true;
+	struct sh_pfc_pin_config *cfg;
 	unsigned int i;
 	int ret = 0;
+	int idx;
 
 	for (i = 0; i < grp->nr_pins; ++i) {
-		int idx = sh_pfc_get_pin_index(pfc, grp->pins[i]);
-		struct sh_pfc_pin_config *cfg = &pmx->configs[idx];
+		idx = sh_pfc_get_pin_index(pfc, grp->pins[i]);
+		cfg = &pmx->configs[idx];
 
 		if (cfg->type != PINMUX_TYPE_NONE) {
+			if (!strcmp(cfg->name, grp->name))
+				continue;
+
+			dev_err(pfc->dev, "Pin already used as %s\n",
+				cfg->name);
 			ret = -EBUSY;
 			goto done;
+		} else {
+			grp_pins_configured = false;
 		}
 	}
 
+	if (grp_pins_configured)
+		return 0;
+
 	for (i = 0; i < grp->nr_pins; ++i) {
 		ret = sh_pfc_config_mux(pfc, grp->mux[i], PINMUX_TYPE_FUNCTION);
 		if (ret < 0)
 			break;
+
+		idx = sh_pfc_get_pin_index(pfc, grp->pins[i]);
+		cfg = &pmx->configs[idx];
+		cfg->type = PINMUX_TYPE_FUNCTION;
+		cfg->name = priv->pfc.info->groups[group_selector].name;
 	}
 
 done:
@@ -805,6 +846,7 @@ static int sh_pfc_map_pins(struct sh_pfc *pfc, struct sh_pfc_pinctrl *pmx)
 	for (i = 0; i < pfc->info->nr_pins; ++i) {
 		struct sh_pfc_pin_config *cfg = &pmx->configs[i];
 		cfg->type = PINMUX_TYPE_NONE;
+		cfg->name = "none";
 	}
 
 	return 0;
-- 
2.17.1