bcm2835-i2s: Register PCM device

Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit ba46b49 ("ASoC: Add
support for BCM2708")

This driver adds support for digital audio (I2S)
for the BCM2708 SoC that is used by the
Raspberry Pi. External audio codecs can be
connected to the Raspberry Pi via P5 header.

It relies on cyclic DMA engine support for BCM2708.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

Signed-off-by: Matthias Reichl <hias@horus.com>

sound/soc/bcm/bcm2835-i2s.c

@@ -799,6 +799,25 @@ static const struct snd_soc_component_driver bcm2835_i2s_component = {
 	.name		= "bcm2835-i2s-comp",
 };
 
+static const struct snd_pcm_hardware bcm2835_pcm_hardware = {
+	.info			= SNDRV_PCM_INFO_INTERLEAVED |
+				  SNDRV_PCM_INFO_JOINT_DUPLEX,
+	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
+				  SNDRV_PCM_FMTBIT_S24_LE |
+				  SNDRV_PCM_FMTBIT_S32_LE,
+	.period_bytes_min	= 32,
+	.period_bytes_max	= 64 * PAGE_SIZE,
+	.periods_min		= 2,
+	.periods_max		= 255,
+	.buffer_bytes_max	= 128 * PAGE_SIZE,
+};
+
+static const struct snd_dmaengine_pcm_config bcm2835_dmaengine_pcm_config = {
+	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
+	.pcm_hardware = &bcm2835_pcm_hardware,
+	.prealloc_buffer_size = 256 * PAGE_SIZE,
+};
+
 static int bcm2835_i2s_probe(struct platform_device *pdev)
 {
 	struct bcm2835_i2s_dev *dev;
@@ -870,7 +889,9 @@ static int bcm2835_i2s_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
+	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
+			&bcm2835_dmaengine_pcm_config,
+			SND_DMAENGINE_PCM_FLAG_COMPAT);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not register PCM: %d\n", ret);
 		return ret;