i2c: mux: demux-pinctrl: make drivers with no pinctrl work again

Some drivers like i2c-gpio do not have dedicated pinctrl states. They
broke when error checking for pinctrl was added. Detect them now, and in
their case, simply skip over pinctrl configuration.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
index b3893f6282ba..3e6fe1760d82 100644
--- a/drivers/i2c/muxes/i2c-demux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -69,10 +69,28 @@ static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 ne
                 goto err_with_revert;
         }
 
-        p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
+        /*
+         * Check if there are pinctrl states at all. Note: we cant' use
+         * devm_pinctrl_get_select() because we need to distinguish between
+         * the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state().
+         */
+        p = devm_pinctrl_get(adap->dev.parent);
         if (IS_ERR(p)) {
                 ret = PTR_ERR(p);
-                goto err_with_put;
+                /* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */
+                if (ret != -ENODEV)
+                        goto err_with_put;
+        } else {
+                /* there are states. check and use them */
+                struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name);
+
+                if (IS_ERR(s)) {
+                        ret = PTR_ERR(s);
+                        goto err_with_put;
+                }
+                ret = pinctrl_select_state(p, s);
+                if (ret < 0)
+                        goto err_with_put;
         }
 
         priv->chan[new_chan].parent_adap = adap;