[PATCH v2 2/3] i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()

Herve Codina
2023-10-19T10:10:35Z

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>
Acked-by: Peter Rosin <peda@axentia.se>
---
drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
index 22f2280eab7f..9f2e4aa28159 100644
--- a/drivers/i2c/muxes/i2c-demux-pinctrl.c
+++ b/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;
--
2.41.0