ASoC: simple-card: set cpu dai clk in hw_params

The simple-card driver currently accepts a clock node in the cpu dai
sub-node and only uses it as an alternative to the
'system-clock-frequency' property to get the current frequency.

This patch adds another use of the passed clock node. If mclk-fs is
specified, the clocks in cpu and codec dai sub-nodes will be set to
the calculated rate (stream rate * mclk_fs) in hw_params.

This allows platforms to pass tuneable clocks as phandle that will
automatically be set to the right rates.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/simple-card.txt b/Documentation/devicetree/bindings/sound/simple-card.txt
index 17c13e74667d..a4c72d09cd45 100644
--- a/Documentation/devicetree/bindings/sound/simple-card.txt
+++ b/Documentation/devicetree/bindings/sound/simple-card.txt
@@ -86,6 +86,11 @@ Optional CPU/CODEC subnodes properties:
                                           in dai startup() and disabled with
                                           clk_disable_unprepare() in dai
                                           shutdown().
+                                          If a clock is specified and a
+                                          multiplication factor is given with
+                                          mclk-fs, the clock will be set to the
+                                          calculated mclk frequency when the
+                                          stream starts.
 - system-clock-direction-out            : specifies clock direction as 'out' on
                                           initialization. It is useful for some aCPUs with
                                           fixed clocks.
diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c
index 6959a74a6f49..4a516c428b3d 100644
--- a/sound/soc/generic/simple-card.c
+++ b/sound/soc/generic/simple-card.c
@@ -135,6 +135,18 @@ static void asoc_simple_card_shutdown(struct snd_pcm_substream *substream)
         asoc_simple_card_clk_disable(&dai_props->codec_dai);
 }
 
+static int asoc_simple_set_clk_rate(struct asoc_simple_dai *simple_dai,
+                                    unsigned long rate)
+{
+        if (!simple_dai->clk)
+                return 0;
+
+        if (clk_get_rate(simple_dai->clk) == rate)
+                return 0;
+
+        return clk_set_rate(simple_dai->clk, rate);
+}
+
 static int asoc_simple_card_hw_params(struct snd_pcm_substream *substream,
                                       struct snd_pcm_hw_params *params)
 {
@@ -154,6 +166,15 @@ static int asoc_simple_card_hw_params(struct snd_pcm_substream *substream,
 
         if (mclk_fs) {
                 mclk = params_rate(params) * mclk_fs;
+
+                ret = asoc_simple_set_clk_rate(&dai_props->codec_dai, mclk);
+                if (ret < 0)
+                        return ret;
+
+                ret = asoc_simple_set_clk_rate(&dai_props->cpu_dai, mclk);
+                if (ret < 0)
+                        return ret;
+
                 ret = snd_soc_dai_set_sysclk(codec_dai, 0, mclk,
                                              SND_SOC_CLOCK_IN);
                 if (ret && ret != -ENOTSUPP)