[PATCH] ASoC: wm8904: fix automatic sysclk configuration

[Michael Walle <michael@walle.cc>]

The simple-card tries to signal the codec to disable rate constraints,
see commit 2458adb8f92a ("SoC: simple-card-utils: set 0Hz to sysclk when
shutdown"). This wasn't handled by the codec, instead it would set the
FLL frequency to 0Hz which isn't working. Since we don't have any rate
constraints just ignore this request.

Fixes: 13409d27cb39 ("ASoC: wm8904: configure sysclk/FLL automatically")
Signed-off-by: Michael Walle <michael@walle.cc>
---
 sound/soc/codecs/wm8904.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/soc/codecs/wm8904.c b/sound/soc/codecs/wm8904.c
index 7d7ea15d73e0..5ffbaddd6e49 100644
--- a/sound/soc/codecs/wm8904.c
+++ b/sound/soc/codecs/wm8904.c
@@ -1806,6 +1806,12 @@ static int wm8904_set_sysclk(struct snd_soc_dai *dai, int clk_id,
 
 	switch (clk_id) {
 	case WM8904_CLK_AUTO:
+		/* We don't have any rate constraints, so just ignore the
+		 * request to disable constraining.
+		 */
+		if (!freq)
+			return 0;
+
 		mclk_freq = clk_get_rate(priv->mclk);
 		/* enable FLL if a different sysclk is desired */
 		if (mclk_freq != freq) {
-- 
2.20.1