ASoC: codecs: Add support for PCM1789

Add Texas Instruments's PCM1789 DAC support.
It is a simple DAC and does not have many registers.

One particularity about this DAC is that the clocks must be
always enabled. Also, an entire software reset is necessary
while starting to play a sound otherwise, the clocks are not
synchronized (so the DAC is not able to send data).

Signed-off-by: Mylène Josserand <mylene.josserand@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/pcm1789.h

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+// Definitions for PCM1789 audio driver
+// Copyright (C) 2018 Bootlin
+// Mylène Josserand <mylene.josserand@bootlin.com>
+
+#ifndef __PCM1789_H__
+#define __PCM1789_H__
+
+#define PCM1789_FORMATS (SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S24_LE | \
+			 SNDRV_PCM_FMTBIT_S16_LE)
+
+extern const struct regmap_config pcm1789_regmap_config;
+
+int pcm1789_common_init(struct device *dev, struct regmap *regmap);
+int pcm1789_common_exit(struct device *dev);
+
+#endif