[PATCH] ASoC: adau1761: Reset codec at probe and shutdown

[Niklas Carlsson]

From: Niklas Carlsson <niklasc at axis.com>

ADAU1X61 doesn't have a reset pin, which leads to the codec retaining
the register values after the device has been rebooted without a power
cycle. This causes the driver to be out of sync with the codec.

Simulating a hardware reset ensures that the codec is in a defined
state.

Link: https://lore.kernel.org/all/alpine.DEB.2.02.1603291544160.3594@lnxricardw1.se.axis.com/
Link: https://lore.kernel.org/all/alpine.DEB.2.02.1604211547540.31333@lnxricardw1.se.axis.com/
Signed-off-by: Niklas Carlsson <niklasc at axis.com>
---
 sound/soc/codecs/adau1761-i2c.c |  6 +++++
 sound/soc/codecs/adau1761-spi.c |  6 +++++
 sound/soc/codecs/adau1761.c     | 43 +++++++++++++++++++++++++++++++++
 sound/soc/codecs/adau1761.h     |  1 +
 4 files changed, 56 insertions(+)

diff --git a/sound/soc/codecs/adau1761-i2c.c b/sound/soc/codecs/adau1761-i2c.c
index 0683caf86aea..23bffbd74469 100644
--- a/sound/soc/codecs/adau1761-i2c.c
+++ b/sound/soc/codecs/adau1761-i2c.c
@@ -36,6 +36,11 @@ static int adau1761_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+static void adau1761_i2c_shutdown(struct i2c_client *client)
+{
+	adau1761_shutdown(&client->dev);
+}
+
 static const struct i2c_device_id adau1761_i2c_ids[] = {
 	{ "adau1361", ADAU1361 },
 	{ "adau1461", ADAU1761 },
@@ -63,6 +68,7 @@ static struct i2c_driver adau1761_i2c_driver = {
 	},
 	.probe_new = adau1761_i2c_probe,
 	.remove = adau1761_i2c_remove,
+	.shutdown = adau1761_i2c_shutdown,
 	.id_table = adau1761_i2c_ids,
 };
 module_i2c_driver(adau1761_i2c_driver);
diff --git a/sound/soc/codecs/adau1761-spi.c b/sound/soc/codecs/adau1761-spi.c
index 7c9242c2ff94..5bbbc3d3b5be 100644
--- a/sound/soc/codecs/adau1761-spi.c
+++ b/sound/soc/codecs/adau1761-spi.c
@@ -50,6 +50,11 @@ static void adau1761_spi_remove(struct spi_device *spi)
 	adau17x1_remove(&spi->dev);
 }
 
+static void adau1761_spi_shutdown(struct spi_device *spi)
+{
+	adau1761_shutdown(&spi->dev);
+}
+
 static const struct spi_device_id adau1761_spi_id[] = {
 	{ "adau1361", ADAU1361 },
 	{ "adau1461", ADAU1761 },
@@ -77,6 +82,7 @@ static struct spi_driver adau1761_spi_driver = {
 	},
 	.probe = adau1761_spi_probe,
 	.remove = adau1761_spi_remove,
+	.shutdown = adau1761_spi_shutdown,
 	.id_table = adau1761_spi_id,
 };
 module_spi_driver(adau1761_spi_driver);
diff --git a/sound/soc/codecs/adau1761.c b/sound/soc/codecs/adau1761.c
index 8f887227981f..ac544e1e8dc7 100644
--- a/sound/soc/codecs/adau1761.c
+++ b/sound/soc/codecs/adau1761.c
@@ -974,6 +974,39 @@ static struct snd_soc_dai_driver adau1761_dai_driver = {
 	.ops = &adau17x1_dai_ops,
 };
 
+static void adau1761_reset(struct regmap *regmap)
+{
+	size_t i;
+
+	/*
+	 * Handle the lack of a reset pin in ADAU1X61 by manually writing all
+	 * registers to their default values.
+	 *
+	 * Steps for performing the reset:
+	 *   1) Make sure that the cache is marked as dirty by writing all
+	 *      default values directly to the cache.
+	 *
+	 *   2) Enable the core clock which is needed for writing all registers
+	 *      except CLOCK_CONTROL.
+	 *
+	 *   3) Use regcache_sync() for synchronizing the dirty cache back to
+	 *      the hardware.
+	 */
+
+	regcache_cache_only(regmap, true);
+	for (i = 0; i < ARRAY_SIZE(adau1761_reg_defaults); i++)
+		regmap_write(regmap, adau1761_reg_defaults[i].reg,
+			     adau1761_reg_defaults[i].def);
+	regcache_cache_only(regmap, false);
+
+	regmap_update_bits(regmap, ADAU17X1_CLOCK_CONTROL,
+			   ADAU17X1_CLOCK_CONTROL_SYSCLK_EN,
+			   ADAU17X1_CLOCK_CONTROL_SYSCLK_EN);
+	regcache_sync(regmap);
+	regmap_update_bits(regmap, ADAU17X1_CLOCK_CONTROL,
+			   ADAU17X1_CLOCK_CONTROL_SYSCLK_EN, 0);
+}
+
 int adau1761_probe(struct device *dev, struct regmap *regmap,
 	enum adau17x1_type type, void (*switch_mode)(struct device *dev))
 {
@@ -997,6 +1030,8 @@ int adau1761_probe(struct device *dev, struct regmap *regmap,
 	if (ret)
 		return ret;
 
+	adau1761_reset(regmap);
+
 	/* Enable cache only mode as we could miss writes before bias level
 	 * reaches standby and the core clock is enabled */
 	regcache_cache_only(regmap, true);
@@ -1006,6 +1041,14 @@ int adau1761_probe(struct device *dev, struct regmap *regmap,
 }
 EXPORT_SYMBOL_GPL(adau1761_probe);
 
+void adau1761_shutdown(struct device *dev)
+{
+	struct adau *adau = dev_get_drvdata(dev);
+
+	adau1761_reset(adau->regmap);
+}
+EXPORT_SYMBOL_GPL(adau1761_shutdown);
+
 const struct regmap_config adau1761_regmap_config = {
 	.val_bits = 8,
 	.reg_bits = 16,
diff --git a/sound/soc/codecs/adau1761.h b/sound/soc/codecs/adau1761.h
index 7beabf448ad1..98d698ebde27 100644
--- a/sound/soc/codecs/adau1761.h
+++ b/sound/soc/codecs/adau1761.h
@@ -16,6 +16,7 @@ struct device;
 
 int adau1761_probe(struct device *dev, struct regmap *regmap,
 	enum adau17x1_type type, void (*switch_mode)(struct device *dev));
+void adau1761_shutdown(struct device *dev);
 
 extern const struct regmap_config adau1761_regmap_config;
 
-- 
2.30.2