i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()

i2c-demux-pinctrl uses the pair of_find_i2c_adapter_by_node() /
i2c_put_adapter(). These pair alone is not correct to properly lock the
I2C parent adapter.

Indeed, i2c_put_adapter() decrements the module refcount while
of_find_i2c_adapter_by_node() does not increment it. This leads to an
underflow of the parent module refcount.

Use the	dedicated function, of_get_i2c_adapter_by_node(), to handle
correctly the module refcount.

Fixes: 50a5ba8 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Herve Codina <[email protected]>
Cc: [email protected]
Acked-by: Peter Rosin <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>

Author: hcodina

drivers/i2c/muxes/i2c-demux-pinctrl.c

@@ -61,7 +61,7 @@ static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 ne
 	if (ret)
 		goto err;
 
-	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
+	adap = of_get_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
 	if (!adap) {
 		ret = -ENODEV;
 		goto err_with_revert;