ASoC: mxs-saif: fix clock prepare and enable unbalance issue

Currently we directly call a clock_enable in trigger function without
a clk_prepare as pair first.
This will cause system hang immediately when run capture because
the clock was not prepared(playback does not hang because the clock was
prepared already by get_mclk before), a warning message in clock framework
may cause a deadlock to reclaim clock lock (see: pl011_console_write).

Here we prepare clock first in hw_param, then enable it in trigger
function to guarantee the balance.

Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c
index aba71bfa33b1..fdbb36aa9cf5 100644
--- a/sound/soc/mxs/mxs-saif.c
+++ b/sound/soc/mxs/mxs-saif.c
@@ -394,9 +394,14 @@ static int mxs_saif_hw_params(struct snd_pcm_substream *substream,
                              struct snd_soc_dai *cpu_dai)
 {
         struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
+        struct mxs_saif *master_saif;
         u32 scr, stat;
         int ret;
 
+        master_saif = mxs_saif_get_master(saif);
+        if (!master_saif)
+                return -EINVAL;
+
         /* mclk should already be set */
         if (!saif->mclk && saif->mclk_in_use) {
                 dev_err(cpu_dai->dev, "set mclk first\n");
@@ -420,6 +425,11 @@ static int mxs_saif_hw_params(struct snd_pcm_substream *substream,
                 return ret;
         }
 
+        /* prepare clk in hw_param, enable in trigger */
+        clk_prepare(saif->clk);
+        if (saif != master_saif)
+                clk_prepare(master_saif->clk);
+
         scr = __raw_readl(saif->base + SAIF_CTRL);
 
         scr &= ~BM_SAIF_CTRL_WORD_LENGTH;