ASoC: tlv320aic3x: fix reset gpio reference counting

This patch fixes a bug that prevents freeing the reset gpio on unloading
the module.

aic3x_i2c_probe is called when loading the module and it calls list_add
with a probably uninitialized list entry aic3x->list (next = prev = NULL)).
So even if list_del is called it does nothing and in the end the gpio_reset
is not freed. Then a repeated module probing fails silently because
gpio_request fails.

When moving INIT_LIST_HEAD to aic3x_i2c_probe we also have to move
list_del to aic3x_i2c_remove because aic3x_remove may be called
multiple times without aic3x_i2c_remove being called which leads to
a NULL pointer dereference.

Signed-off-by: Philipp Puschmann <philipp.puschmann@emlix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/tlv320aic3x.c b/sound/soc/codecs/tlv320aic3x.c
index 6aa0edf8c5ef92115da50adc8b775235fa60d7ec..cea3ebecdb12b5e437f5621c8941b2e31b413ce3 100644 (file)
--- a/sound/soc/codecs/tlv320aic3x.c
+++ b/sound/soc/codecs/tlv320aic3x.c
@@ -1609,7 +1609,6 @@ static int aic3x_probe(struct snd_soc_component *component)
        struct aic3x_priv *aic3x = snd_soc_component_get_drvdata(component);
        int ret, i;
 
-       INIT_LIST_HEAD(&aic3x->list);
        aic3x->component = component;
 
        for (i = 0; i < ARRAY_SIZE(aic3x->supplies); i++) {
@@ -1692,7 +1691,6 @@ static void aic3x_remove(struct snd_soc_component *component)
        struct aic3x_priv *aic3x = snd_soc_component_get_drvdata(component);
        int i;
 
-       list_del(&aic3x->list);
        for (i = 0; i < ARRAY_SIZE(aic3x->supplies); i++)
                regulator_unregister_notifier(aic3x->supplies[i].consumer,
                                              &aic3x->disable_nb[i].nb);
@@ -1890,6 +1888,7 @@ static int aic3x_i2c_probe(struct i2c_client *i2c,
        if (ret != 0)
                goto err_gpio;
 
+       INIT_LIST_HEAD(&aic3x->list);
        list_add(&aic3x->list, &reset_list);
 
        return 0;
@@ -1906,6 +1905,8 @@ static int aic3x_i2c_remove(struct i2c_client *client)
 {
        struct aic3x_priv *aic3x = i2c_get_clientdata(client);
 
+       list_del(&aic3x->list);
+
        if (gpio_is_valid(aic3x->gpio_reset) &&
            !aic3x_is_shared_reset(aic3x)) {
                gpio_set_value(aic3x->gpio_reset, 0);