ASoC: make clock direction configurable in asoc-simple

Some CPU drivers (e. g. davinci-mcasp) may require the system clock to
be configured as OUT, while there's no good way currently to set
SND_SOC_CLK_OUT in simple-soc driver if the clock is fixed-rate.

This patch makes asoc_simple_card_init_dai() initialize clock to
SND_SOCK_CLK_OUT if explicitly stated in the relevant dts file. This
change is transparent and doesn't change the default behavior.

Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

3 files changed, 11 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/sound/simple-card.txt b/Documentation/devicetree/bindings/sound/simple-card.txt
index c7a93931fad2..166f2290233b 100644
--- a/Documentation/devicetree/bindings/sound/simple-card.txt
+++ b/Documentation/devicetree/bindings/sound/simple-card.txt
@@ -86,6 +86,9 @@ Optional CPU/CODEC subnodes properties:
                                           in dai startup() and disabled with
                                           clk_disable_unprepare() in dai
                                           shutdown().
+- system-clock-direction-out            : specifies clock direction as 'out' on
+                                          initialization. It is useful for some aCPUs with
+                                          fixed clocks.
 
 Example 1 - single DAI link:
 
diff --git a/include/sound/simple_card_utils.h b/include/sound/simple_card_utils.h
index 42c6a6ac3ce6..7e25afce6566 100644
--- a/include/sound/simple_card_utils.h
+++ b/include/sound/simple_card_utils.h
@@ -15,6 +15,7 @@
 struct asoc_simple_dai {
         const char *name;
         unsigned int sysclk;
+        int clk_direction;
         int slots;
         int slot_width;
         unsigned int tx_slot_mask;
diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
index 26d64fa40c9c..af44c8c52a19 100644
--- a/sound/soc/generic/simple-card-utils.c
+++ b/sound/soc/generic/simple-card-utils.c
@@ -196,7 +196,11 @@ int asoc_simple_card_parse_clk(struct device *dev,
                         simple_dai->sysclk = clk_get_rate(clk);
         }
 
-        dev_dbg(dev, "%s : sysclk = %d\n", name, simple_dai->sysclk);
+        if (of_property_read_bool(node, "system-clock-direction-out"))
+                simple_dai->clk_direction = SND_SOC_CLOCK_OUT;
+
+        dev_dbg(dev, "%s : sysclk = %d, direction %d\n", name,
+                simple_dai->sysclk, simple_dai->clk_direction);
 
         return 0;
 }
@@ -310,7 +314,8 @@ int asoc_simple_card_init_dai(struct snd_soc_dai *dai,
         int ret;
 
         if (simple_dai->sysclk) {
-                ret = snd_soc_dai_set_sysclk(dai, 0, simple_dai->sysclk, 0);
+                ret = snd_soc_dai_set_sysclk(dai, 0, simple_dai->sysclk,
+                                             simple_dai->clk_direction);
                 if (ret && ret != -ENOTSUPP) {
                         dev_err(dai->dev, "simple-card: set_sysclk error\n");
                         return ret;