i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()
authorHerve Codina <herve.codina@bootlin.com>
Fri, 20 Oct 2023 15:30:12 +0000 (17:30 +0200)
committerWolfram Sang <wsa@kernel.org>
Sat, 21 Oct 2023 17:56:55 +0000 (19:56 +0200)
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: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Cc: stable@vger.kernel.org
Acked-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
drivers/i2c/muxes/i2c-demux-pinctrl.c

index 22f2280..9f2e4aa 100644 (file)
@@ -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;