[ALSA] ALSA sound driver for the AT73C213 DAC using Atmel SSC driver

This patch adds support for the AT73C213 DAC using the misc Atmel SSC driver in
I2S mode. The driver also requires a SPI to setup the registers and control
volume.
It has been tested with an AT32AP7000 on the ATSTK1000 development board. The
driver should also work with any Atmel device with an SSC module supported by
the Atmel SSC driver (atmel-ssc).
The atmel-ssc driver is just submitted to the Linux kernel. Please see mail
thread http://lkml.org/lkml/2007/7/16/32

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

include/linux/spi/at73c213.h

@@ -0,0 +1,25 @@
+/*
+ * Board-specific data used to set up AT73c213 audio DAC driver.
+ */
+
+#ifndef __LINUX_SPI_AT73C213_H
+#define __LINUX_SPI_AT73C213_H
+
+/**
+ * at73c213_board_info - how the external DAC is wired to the device.
+ *
+ * @ssc_id: SSC platform_driver id the DAC shall use to stream the audio.
+ * @dac_clk: the external clock used to provide master clock to the DAC.
+ * @shortname: a short discription for the DAC, seen by userspace tools.
+ *
+ * This struct contains the configuration of the hardware connection to the
+ * external DAC. The DAC needs a master clock and a I2S audio stream. It also
+ * provides a name which is used to identify it in userspace tools.
+ */
+struct at73c213_board_info {
+	int		ssc_id;
+	struct clk	*dac_clk;
+	char		shortname[32];
+};
+
+#endif /* __LINUX_SPI_AT73C213_H */

sound/spi/Kconfig

@@ -3,4 +3,29 @@
 menu "SPI devices"
 	depends on SND != n
 
+config SND_AT73C213
+	tristate "Atmel AT73C213 DAC driver"
+	depends on ATMEL_SSC
+	select SND_PCM
+	help
+	  Say Y here if you want to use the Atmel AT73C213 external DAC. This
+	  DAC can be found on Atmel development boards.
+
+	  This driver requires the Atmel SSC driver for sound sink, a
+	  peripheral found on most AT91 and AVR32 microprocessors.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called snd-at73c213.
+
+config SND_AT73C213_TARGET_BITRATE
+	int "Target bitrate for AT73C213"
+	depends on SND_AT73C213
+	default "48000"
+	range 8000 50000
+	help
+	  Sets the target bitrate for the bitrate calculator in the driver.
+	  Limited by hardware to be between 8000 Hz and 50000 Hz.
+
+	  Set to 48000 Hz by default.
+
 endmenu

sound/spi/Makefile

@@ -1,2 +1,5 @@
 # Makefile for SPI drivers
 
+snd-at73c213-objs		:= at73c213.o
+
+obj-$(CONFIG_SND_AT73C213)	+= snd-at73c213.o

sound/spi/at73c213.h

@@ -0,0 +1,119 @@
+/*
+ * Driver for the AT73C213 16-bit stereo DAC on Atmel ATSTK1000
+ *
+ * Copyright (C) 2006 - 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * The full GNU General Public License is included in this
+ * distribution in the file called COPYING.
+ */
+
+#ifndef _SND_AT73C213_H
+#define _SND_AT73C213_H
+
+/* DAC control register */
+#define DAC_CTRL		0x00
+#define DAC_CTRL_ONPADRV	7
+#define DAC_CTRL_ONAUXIN	6
+#define DAC_CTRL_ONDACR		5
+#define DAC_CTRL_ONDACL		4
+#define DAC_CTRL_ONLNOR		3
+#define DAC_CTRL_ONLNOL		2
+#define DAC_CTRL_ONLNIR		1
+#define DAC_CTRL_ONLNIL		0
+
+/* DAC left line in gain register */
+#define DAC_LLIG		0x01
+#define DAC_LLIG_LLIG		0
+
+/* DAC right line in gain register */
+#define DAC_RLIG		0x02
+#define DAC_RLIG_RLIG		0
+
+/* DAC Left Master Playback Gain Register */
+#define DAC_LMPG		0x03
+#define DAC_LMPG_LMPG		0
+
+/* DAC Right Master Playback Gain Register */
+#define DAC_RMPG		0x04
+#define DAC_RMPG_RMPG		0
+
+/* DAC Left Line Out Gain Register */
+#define DAC_LLOG		0x05
+#define DAC_LLOG_LLOG		0
+
+/* DAC Right Line Out Gain Register */
+#define DAC_RLOG		0x06
+#define DAC_RLOG_RLOG		0
+
+/* DAC Output Level Control Register */
+#define DAC_OLC			0x07
+#define DAC_OLC_RSHORT		7
+#define DAC_OLC_ROLC		4
+#define DAC_OLC_LSHORT		3
+#define DAC_OLC_LOLC		0
+
+/* DAC Mixer Control Register */
+#define DAC_MC			0x08
+#define DAC_MC_INVR		5
+#define DAC_MC_INVL		4
+#define DAC_MC_RMSMIN2		3
+#define DAC_MC_RMSMIN1		2
+#define DAC_MC_LMSMIN2		1
+#define DAC_MC_LMSMIN1		0
+
+/* DAC Clock and Sampling Frequency Control Register */
+#define DAC_CSFC		0x09
+#define DAC_CSFC_OVRSEL		4
+
+/* DAC Miscellaneous Register */
+#define DAC_MISC		0x0A
+#define DAC_MISC_VCMCAPSEL	7
+#define DAC_MISC_DINTSEL	4
+#define DAC_MISC_DITHEN		3
+#define DAC_MISC_DEEMPEN	2
+#define DAC_MISC_NBITS		0
+
+/* DAC Precharge Control Register */
+#define DAC_PRECH		0x0C
+#define DAC_PRECH_PRCHGPDRV	7
+#define DAC_PRECH_PRCHGAUX1	6
+#define DAC_PRECH_PRCHGLNOR	5
+#define DAC_PRECH_PRCHGLNOL	4
+#define DAC_PRECH_PRCHGLNIR	3
+#define DAC_PRECH_PRCHGLNIL	2
+#define DAC_PRECH_PRCHG		1
+#define DAC_PRECH_ONMSTR	0
+
+/* DAC Auxiliary Input Gain Control Register */
+#define DAC_AUXG		0x0D
+#define DAC_AUXG_AUXG		0
+
+/* DAC Reset Register */
+#define DAC_RST			0x10
+#define DAC_RST_RESMASK		2
+#define DAC_RST_RESFILZ		1
+#define DAC_RST_RSTZ		0
+
+/* Power Amplifier Control Register */
+#define PA_CTRL			0x11
+#define PA_CTRL_APAON		6
+#define PA_CTRL_APAPRECH	5
+#define PA_CTRL_APALP		4
+#define PA_CTRL_APAGAIN		0
+
+#endif /* _SND_AT73C213_H */