ASoC: msm8960: properly protect external mclk control function
Both audio path and MBHC accessory detection logic need master clock
enabled along with bandgap and clock block of CODEC. Clock control
is managed by the machine driver. Calls to clock control function from
audio and MBHC detection paths can be nested. As a result, reference
counter of master clock is incremen/decrement out of order and cause
master clock not enabled when audio path is enabled. Without master clock
CODEC will not consume data and this leads to SLIMBUS overflow error.
Change-Id: I2cabb2d6db4c0129716489672e34a49cc21cea08
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
diff --git a/sound/soc/msm/msm8960.c b/sound/soc/msm/msm8960.c
index e342469..0d45e82 100644
--- a/sound/soc/msm/msm8960.c
+++ b/sound/soc/msm/msm8960.c
@@ -98,6 +98,8 @@
.gpio_level_insert = 1,
};
+static struct mutex cdc_mclk_mutex;
+
static void msm8960_enable_ext_spk_amp_gpio(u32 spk_amp_gpio)
{
int ret = 0;
@@ -322,35 +324,42 @@
static int msm8960_enable_codec_ext_clk(struct snd_soc_codec *codec, int enable,
bool dapm)
{
+ int r = 0;
pr_debug("%s: enable = %d\n", __func__, enable);
+
+ mutex_lock(&cdc_mclk_mutex);
if (enable) {
clk_users++;
pr_debug("%s: clk_users = %d\n", __func__, clk_users);
- if (clk_users != 1)
- return 0;
-
- if (codec_clk) {
- clk_set_rate(codec_clk, TABLA_EXT_CLK_RATE);
- clk_enable(codec_clk);
- tabla_mclk_enable(codec, 1, dapm);
- } else {
- pr_err("%s: Error setting Tabla MCLK\n", __func__);
- clk_users--;
- return -EINVAL;
+ if (clk_users == 1) {
+ if (codec_clk) {
+ clk_set_rate(codec_clk, TABLA_EXT_CLK_RATE);
+ clk_enable(codec_clk);
+ tabla_mclk_enable(codec, 1, dapm);
+ } else {
+ pr_err("%s: Error setting Tabla MCLK\n",
+ __func__);
+ clk_users--;
+ r = -EINVAL;
+ }
}
} else {
- pr_debug("%s: clk_users = %d\n", __func__, clk_users);
- if (clk_users == 0)
- return 0;
- clk_users--;
- if (!clk_users) {
- pr_debug("%s: disabling MCLK. clk_users = %d\n",
+ if (clk_users > 0) {
+ clk_users--;
+ pr_debug("%s: clk_users = %d\n", __func__, clk_users);
+ if (clk_users == 0) {
+ pr_debug("%s: disabling MCLK. clk_users = %d\n",
__func__, clk_users);
- clk_disable(codec_clk);
- tabla_mclk_enable(codec, 0, dapm);
+ clk_disable(codec_clk);
+ tabla_mclk_enable(codec, 0, dapm);
+ }
+ } else {
+ pr_err("%s: Error releasing Tabla MCLK\n", __func__);
+ r = -EINVAL;
}
}
- return 0;
+ mutex_unlock(&cdc_mclk_mutex);
+ return r;
}
static int msm8960_mclk_event(struct snd_soc_dapm_widget *w,
@@ -1486,6 +1495,7 @@
} else
msm8960_headset_gpios_configured = 1;
+ mutex_init(&cdc_mclk_mutex);
return ret;
}
@@ -1501,6 +1511,7 @@
platform_device_unregister(msm8960_snd_device);
platform_device_unregister(msm8960_snd_tabla1x_device);
kfree(mbhc_cfg.calibration);
+ mutex_destroy(&cdc_mclk_mutex);
}
module_exit(msm8960_audio_exit);