dm: sound: Create a uclass for audio codecs

An audio codec provides a way to convert digital data to sound and vice
versa. Add a simple uclass which just supports setting the parameters for
the codec.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/dts/test.dts

@@ -42,7 +42,12 @@
 		osd0 = "/osd";
 	};
 
-	cros_ec: cros-ec {
+	audio: audio-codec {
+		compatible = "sandbox,audio-codec";
+		#sound-dai-cells = <1>;
+	};
+
+		cros_ec: cros-ec {
 		reg = <0 0>;
 		compatible = "google,cros-ec-sandbox";
 

arch/sandbox/include/asm/test.h

@@ -121,4 +121,14 @@ int sandbox_pwm_get_config(struct udevice *dev, uint channel, uint *period_nsp,
  */
 void sandbox_sf_set_block_protect(struct udevice *dev, int bp_mask);
 
+/**
+ * sandbox_get_codec_params() - Read back codec parameters
+ *
+ * This reads back the parameters set by audio_codec_set_params() for the
+ * sandbox audio driver. Arguments are as for that function.
+ */
+void sandbox_get_codec_params(struct udevice *dev, int *interfacep, int *ratep,
+			      int *mclk_freqp, int *bits_per_samplep,
+			      uint *channelsp);
+
 #endif

drivers/sound/Makefile

@@ -4,6 +4,7 @@
 # R. Chandrasekar <rcsekar@samsung.com>
 
 obj-$(CONFIG_SOUND)	+= sound.o
+obj-$(CONFIG_DM_SOUND)	+= codec-uclass.o
 obj-$(CONFIG_I2S)	+= sound-i2s.o
 obj-$(CONFIG_I2S_SAMSUNG)	+= samsung-i2s.o
 obj-$(CONFIG_SOUND_SANDBOX)	+= sandbox.o

drivers/sound/codec-uclass.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <audio_codec.h>
+
+int audio_codec_set_params(struct udevice *dev, int interface, int rate,
+			   int mclk_freq, int bits_per_sample, uint channels)
+{
+	struct audio_codec_ops *ops = audio_codec_get_ops(dev);
+
+	if (!ops->set_params)
+		return -ENOSYS;
+
+	return ops->set_params(dev, interface, rate, mclk_freq, bits_per_sample,
+			       channels);
+}
+
+UCLASS_DRIVER(audio_codec) = {
+	.id		= UCLASS_AUDIO_CODEC,
+	.name		= "audio-codec",
+};

drivers/sound/sandbox.c

@@ -4,9 +4,19 @@
  */
 
 #include <common.h>
+#include <dm.h>
+#include <audio_codec.h>
 #include <asm/sound.h>
 #include <asm/sdl.h>
 
+struct sandbox_codec_priv {
+	int interface;
+	int rate;
+	int mclk_freq;
+	int bits_per_sample;
+	uint channels;
+};
+
 int sound_play(uint32_t msec, uint32_t frequency)
 {
 	sandbox_sdl_sound_start(frequency);
@@ -20,3 +30,48 @@ int sound_init(const void *blob)
 {
 	return sandbox_sdl_sound_init();
 }
+
+void sandbox_get_codec_params(struct udevice *dev, int *interfacep, int *ratep,
+			      int *mclk_freqp, int *bits_per_samplep,
+			      uint *channelsp)
+{
+	struct sandbox_codec_priv *priv = dev_get_priv(dev);
+
+	*interfacep = priv->interface;
+	*ratep = priv->rate;
+	*mclk_freqp = priv->mclk_freq;
+	*bits_per_samplep = priv->bits_per_sample;
+	*channelsp = priv->channels;
+}
+
+static int sandbox_codec_set_params(struct udevice *dev, int interface,
+				    int rate, int mclk_freq,
+				    int bits_per_sample, uint channels)
+{
+	struct sandbox_codec_priv *priv = dev_get_priv(dev);
+
+	priv->interface = interface;
+	priv->rate = rate;
+	priv->mclk_freq = mclk_freq;
+	priv->bits_per_sample = bits_per_sample;
+	priv->channels = channels;
+
+	return 0;
+}
+
+static const struct audio_codec_ops sandbox_codec_ops = {
+	.set_params	= sandbox_codec_set_params,
+};
+
+static const struct udevice_id sandbox_codec_ids[] = {
+	{ .compatible = "sandbox,audio-codec" },
+	{ }
+};
+
+U_BOOT_DRIVER(sandbox_codec) = {
+	.name		= "sandbox_codec",
+	.id		= UCLASS_AUDIO_CODEC,
+	.of_match	= sandbox_codec_ids,
+	.ops		= &sandbox_codec_ops,
+	.priv_auto_alloc_size	= sizeof(struct sandbox_codec_priv),
+};

include/audio_codec.h

@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2018 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __AUDIO_CODEC_H__
+#define __AUDIO_CODEC_H__
+
+/*
+ * An audio codec turns digital data into sound with various parameters to
+ * control its operation.
+ */
+
+/* Operations for sound */
+struct audio_codec_ops {
+	/**
+	 * set_params() - Set audio codec parameters
+	 *
+	 * @dev: Sound device
+	 * @inteface: Interface number to use on codec
+	 * @rate: Sampling rate in Hz
+	 * @mclk_freq: Codec clock frequency in Hz
+	 * @bits_per_sample: Must be 16 or 24
+	 * @channels: Number of channels to use (1=mono, 2=stereo)
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_params)(struct udevice *dev, int interface, int rate,
+			  int mclk_freq, int bits_per_sample, uint channels);
+};
+
+#define audio_codec_get_ops(dev) ((struct audio_codec_ops *)(dev)->driver->ops)
+
+/**
+ * audio_codec_set_params() - Set audio codec parameters
+ *
+ * @dev: Sound device
+ * @inteface: Interface number to use on codec
+ * @rate: Sampling rate in Hz
+ * @mclk_freq: Codec clock frequency in Hz
+ * @bits_per_sample: Must be 16 or 24
+ * @channels: Number of channels to use (1=mono, 2=stereo)
+ * @return 0 if OK, -ve on error
+ */
+int audio_codec_set_params(struct udevice *dev, int interface, int rate,
+			   int mclk_freq, int bits_per_sample, uint channels);
+
+#endif  /* __AUDIO_CODEC_H__ */

include/dm/uclass-id.h

@@ -29,6 +29,7 @@ enum uclass_id {
 	/* U-Boot uclasses start here - in alphabetical order */
 	UCLASS_ADC,		/* Analog-to-digital converter */
 	UCLASS_AHCI,		/* SATA disk controller */
+	UCLASS_AUDIO_CODEC,	/* Audio codec with control and data path */
 	UCLASS_AXI,		/* AXI bus */
 	UCLASS_BLK,		/* Block device */
 	UCLASS_BOARD,		/* Device information from hardware */

test/dm/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_UT_DM) += test-uclass.o
 # subsystem you must add sandbox tests here.
 obj-$(CONFIG_UT_DM) += core.o
 ifneq ($(CONFIG_SANDBOX),)
+obj-$(CONFIG_DM_SOUND) += audio.o
 obj-$(CONFIG_BLK) += blk.o
 obj-$(CONFIG_BOARD) += board.o
 obj-$(CONFIG_CLK) += clk.o

test/dm/audio.c

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <audio_codec.h>
+#include <dm.h>
+#include <dm/test.h>
+#include <test/ut.h>
+#include <asm/test.h>
+
+/* Basic test of the audio codec uclass */
+static int dm_test_audio(struct unit_test_state *uts)
+{
+	int interface, rate, mclk_freq, bits_per_sample;
+	struct udevice *dev;
+	uint channels;
+
+	/* check probe success */
+	ut_assertok(uclass_first_device_err(UCLASS_AUDIO_CODEC, &dev));
+	ut_assertok(audio_codec_set_params(dev, 1, 2, 3, 4, 5));
+	sandbox_get_codec_params(dev, &interface, &rate, &mclk_freq,
+				 &bits_per_sample, &channels);
+	ut_asserteq(1, interface);
+	ut_asserteq(2, rate);
+	ut_asserteq(3, mclk_freq);
+	ut_asserteq(4, bits_per_sample);
+	ut_asserteq(5, channels);
+
+	return 0;
+}
+DM_TEST(dm_test_audio, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);