[alsa-devel] [PATCH] ASoC: Intel: bytcr_rt5640: fallback mechanism if MCLK is not enabled

[Pierre-Louis Bossart]

Commit df1a2776a795 ("ASoC: Intel: bytcr_rt5640: add MCLK support")
was merged but the corresponding clock framework patches have not,
after being bumped from audio to clock to x86 domains. The missing
clock-related patches result in a regression starting with 4.9 with
the audio card not being created.

Rather than reverting this commit and all following updates already
queued up for 4.10, handle run-time dependency on MCLK and fall back
to the previous bit-clock mode. This provides the same functionality
as in 4.8 for Baytrail devices. On Baytrail-CR most devices remain
silent with this fallback but additional patches are needed anyway.

This patch should be applied to -stable as well as ASoC 4.10 fixes

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/intel/boards/bytcr_rt5640.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/soc/intel/boards/bytcr_rt5640.c b/sound/soc/intel/boards/bytcr_rt5640.c
index 507a86a..4a8b509 100644
--- a/sound/soc/intel/boards/bytcr_rt5640.c
+++ b/sound/soc/intel/boards/bytcr_rt5640.c
@@ -828,7 +828,9 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
 			dev_err(&pdev->dev,
 				"Failed to get MCLK from pmc_plt_clk_3: %ld\n",
 				PTR_ERR(priv->mclk));
-			return PTR_ERR(priv->mclk);
+
+			/* Fall back to bitclock only */
+			byt_rt5640_quirk &= ~BYT_RT5640_MCLK_EN;
 		}
 	}
 
-- 
2.9.3