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

commit 3171d37b58a76e1febbf3f4af2d06234a98cf88b upstream.

i2c-mux-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: c4aee3e1b0de ("i2c: mux: pinctrl: remove platform_data")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index 18236b9fa14a9558dfb08bf656da442090d4611f..6ebca7bfd8a2652ec5e7bf1abef21a35992d38ac 100644 (file)
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -62,7 +62,7 @@ static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)
                dev_err(dev, "Cannot parse i2c-parent\n");
                return ERR_PTR(-ENODEV);
        }
-       parent = of_find_i2c_adapter_by_node(parent_np);
+       parent = of_get_i2c_adapter_by_node(parent_np);
        of_node_put(parent_np);
        if (!parent)
                return ERR_PTR(-EPROBE_DEFER);