pinctrl: sh-pfc: Rollback to mux if required when the gpio is freed

Some drivers require switching between function and gpio at run-time.
Allow to roll back from gpio to mux when the gpio is freed.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/drivers/pinctrl/sh-pfc/pinctrl.c b/drivers/pinctrl/sh-pfc/pinctrl.c
index ab2aa93..99f4ebd 100644 (file)
--- a/drivers/pinctrl/sh-pfc/pinctrl.c
+++ b/drivers/pinctrl/sh-pfc/pinctrl.c
@@ -26,6 +26,7 @@
 #include "../pinconf.h"
 
 struct sh_pfc_pin_config {
+       unsigned int mux_mark;
        bool mux_set;
        bool gpio_enabled;
 };
@@ -353,6 +354,16 @@ static int sh_pfc_func_set_mux(struct pinctrl_dev *pctldev, unsigned selector,
        spin_lock_irqsave(&pfc->lock, flags);
 
        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];
+
+               /*
+                * This driver cannot manage both gpio and mux when the gpio
+                * pin is already enabled. So, this function fails.
+                */
+               if (cfg->gpio_enabled)
+                       return -EBUSY;
+
                ret = sh_pfc_config_mux(pfc, grp->mux[i], PINMUX_TYPE_FUNCTION);
                if (ret < 0)
                        goto done;
@@ -364,6 +375,7 @@ static int sh_pfc_func_set_mux(struct pinctrl_dev *pctldev, unsigned selector,
                struct sh_pfc_pin_config *cfg = &pmx->configs[idx];
 
                cfg->mux_set = true;
+               cfg->mux_mark = grp->mux[i];
        }
 
 done:
@@ -417,6 +429,9 @@ static void sh_pfc_gpio_disable_free(struct pinctrl_dev *pctldev,
 
        spin_lock_irqsave(&pfc->lock, flags);
        cfg->gpio_enabled = false;
+       /* If mux is already set, this configures it here */
+       if (cfg->mux_set)
+               sh_pfc_config_mux(pfc, cfg->mux_mark, PINMUX_TYPE_FUNCTION);
        spin_unlock_irqrestore(&pfc->lock, flags);
 }