ASoC: blackfin: bf5xx-i2s: Add support for TDM mode

The bf5xx-i2s{,-pcm} and bf5xx-tdm{-pcm} drivers are nearly identical. Both are
for the same hardware each supporting a slight different subset of the hardware.
The bf5xx-i2s driver supports 2 channel I2S mode while the bf5xx-tdm driver
supports TDM mode and channel remapping. This patch adds support for TDM mode
and channel remapping to the bf5xx-i2s driver so that we'll eventually be able
to retire the bf5xx-tdm driver. Unfortunately the hardware is fixed to using 8
channels in TDM mode. The bf5xx-tdm driver jumps through a few hoops to make it
work well with other channel counts as well:
	* Don't support mmap
	* Translate between internal frame size (which is always 8 * sample_size)
	  and ALSA frame size (which depends on the channel count)
	* Have special copy and silence callbacks which are aware of the mismatch
	  between internal and ALSA frame size
	* Reduce the maximum buffer size to ensure that there is enough headroom for
	  dummy data.

The bf5xx-i2s driver is going to use the same mechanisms when being used int
TDM mode.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/sound/soc/blackfin/bf5xx-i2s-pcm.h b/sound/soc/blackfin/bf5xx-i2s-pcm.h
new file mode 100644
index 000000000000..1f0435249f88
--- /dev/null
+++ b/sound/soc/blackfin/bf5xx-i2s-pcm.h
@@ -0,0 +1,17 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _BF5XX_TDM_PCM_H
+#define _BF5XX_TDM_PCM_H
+
+#define BFIN_TDM_DAI_MAX_SLOTS 8
+
+struct bf5xx_i2s_pcm_data {
+	unsigned int map[BFIN_TDM_DAI_MAX_SLOTS];
+	bool tdm_mode;
+};
+
+#endif