The SSC is currently not usable with the ASoC simple-audio-card, as
every SSC audio user has to build a platform driver that may do as
little as calling atmel_ssc_set_audio/atmel_ssc_put_audio (which
allocates the SSC and registers a DAI with the ASoC subsystem).

So, have that happen automatically, if the #sound-dai-cells property
is present in devicetree, which it has to be anyway for simple audio
card to work.

Signed-off-by: Peter Rosin <p...@axentia.se>
---
 .../devicetree/bindings/misc/atmel-ssc.txt         |  2 +
 drivers/misc/atmel-ssc.c                           | 50 ++++++++++++++++++++++
 include/linux/atmel-ssc.h                          |  1 +
 3 files changed, 53 insertions(+)

diff --git a/Documentation/devicetree/bindings/misc/atmel-ssc.txt 
b/Documentation/devicetree/bindings/misc/atmel-ssc.txt
index efc98ea1f23d..f8629bb73945 100644
--- a/Documentation/devicetree/bindings/misc/atmel-ssc.txt
+++ b/Documentation/devicetree/bindings/misc/atmel-ssc.txt
@@ -24,6 +24,8 @@ Optional properties:
        this parameter to choose where the clock from.
      - By default the clock is from TK pin, if the clock from RK pin, this
        property is needed.
+  - #sound-dai-cells: Should contain <0>.
+     - This property makes the SSC into an automatically registered DAI.
 
 Examples:
 - PDC transfer:
diff --git a/drivers/misc/atmel-ssc.c b/drivers/misc/atmel-ssc.c
index 0516ecda54d3..b2a0340f277e 100644
--- a/drivers/misc/atmel-ssc.c
+++ b/drivers/misc/atmel-ssc.c
@@ -20,6 +20,8 @@
 
 #include <linux/of.h>
 
+#include "../../sound/soc/atmel/atmel_ssc_dai.h"
+
 /* Serialize access to ssc_list and user count */
 static DEFINE_SPINLOCK(user_lock);
 static LIST_HEAD(ssc_list);
@@ -145,6 +147,49 @@ static inline const struct atmel_ssc_platform_data * __init
                platform_get_device_id(pdev)->driver_data;
 }
 
+#ifdef CONFIG_SND_ATMEL_SOC_SSC
+static int ssc_sound_dai_probe(struct ssc_device *ssc)
+{
+       struct device_node *np = ssc->pdev->dev.of_node;
+       int ret;
+       int id;
+
+       ssc->sound_dai = false;
+
+       if (!of_property_read_bool(np, "#sound-dai-cells"))
+               return 0;
+
+       id = of_alias_get_id(np, "ssc");
+       if (id < 0)
+               return id;
+
+       ret = atmel_ssc_set_audio(id);
+       ssc->sound_dai = !ret;
+
+       return ret;
+}
+
+static void ssc_sound_dai_remove(struct ssc_device *ssc)
+{
+       if (!ssc->sound_dai)
+               return;
+
+       atmel_ssc_put_audio(of_alias_get_id(ssc->pdev->dev.of_node, "ssc"));
+}
+#else
+static inline int ssc_sound_dai_probe(struct ssc_device *ssc)
+{
+       if (of_property_read_bool(ssc->pdev->dev.of_node, "#sound-dai-cells"))
+               return -ENOTSUPP;
+
+       return 0;
+}
+
+static inline void ssc_sound_dai_remove(struct ssc_device *ssc)
+{
+}
+#endif
+
 static int ssc_probe(struct platform_device *pdev)
 {
        struct resource *regs;
@@ -204,6 +249,9 @@ static int ssc_probe(struct platform_device *pdev)
        dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
                        ssc->regs, ssc->irq);
 
+       if (ssc_sound_dai_probe(ssc))
+               dev_err(&pdev->dev, "failed to auto-setup ssc for audio\n");
+
        return 0;
 }
 
@@ -211,6 +259,8 @@ static int ssc_remove(struct platform_device *pdev)
 {
        struct ssc_device *ssc = platform_get_drvdata(pdev);
 
+       ssc_sound_dai_remove(ssc);
+
        spin_lock(&user_lock);
        list_del(&ssc->list);
        spin_unlock(&user_lock);
diff --git a/include/linux/atmel-ssc.h b/include/linux/atmel-ssc.h
index 7c0f6549898b..fdb545101ede 100644
--- a/include/linux/atmel-ssc.h
+++ b/include/linux/atmel-ssc.h
@@ -20,6 +20,7 @@ struct ssc_device {
        int                     user;
        int                     irq;
        bool                    clk_from_rk_pin;
+       bool                    sound_dai;
 };
 
 struct ssc_device * __must_check ssc_request(unsigned int ssc_num);
-- 
2.1.4

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