[alsa-devel] [PATCH] ASoC: sgtl5000: defer the probe if clock is not found

[Shawn Guo]

It's not always the case that clock is already available when sgtl5000
get probed at the first time, e.g. the clock is provided by CPU DAI
which may be probed after sgtl5000.  So let's defer the probe when
devm_clk_get() call fails and give it chance to try later.

It fixes the following problem on imx28.

[    1.927637] sgtl5000 0-000a: Failed to get mclock: -2
[    1.934280] sgtl5000: probe of 0-000a failed with error -2

Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
---
Mark,

This is a fix for 3.11.

Shawn

 sound/soc/codecs/sgtl5000.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index d441559..7ebf923 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -1527,7 +1527,8 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
 	if (IS_ERR(sgtl5000->mclk)) {
 		ret = PTR_ERR(sgtl5000->mclk);
 		dev_err(&client->dev, "Failed to get mclock: %d\n", ret);
-		return ret;
+		/* Defer the probe to see if the clk will be provided later */
+		return ret == -ENOENT ? -EPROBE_DEFER : ret;
 	}
 
 	ret = clk_prepare_enable(sgtl5000->mclk);
-- 
1.7.9.5