1 files changed, 105 insertions, 0 deletions
diff --git a/sound/soc/soc-cache.c b/sound/soc/soc-cache.c
new file mode 100644
index 000000000000..4eb4333a0efb
--- /dev/null
+++ b/sound/soc/soc-cache.c
@@ -0,0 +1,105 @@
+/*
+ * soc-cache.c  --  ASoC register cache helpers
+ *
+ * Copyright 2009 Wolfson Microelectronics PLC.
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *  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.
+ */
+
+#include <sound/soc.h>
+
+static unsigned int snd_soc_7_9_read(struct snd_soc_codec *codec,
+				     unsigned int reg)
+{
+	u16 *cache = codec->reg_cache;
+	if (reg >= codec->reg_cache_size)
+		return -1;
+	return cache[reg];
+}
+
+static int snd_soc_7_9_write(struct snd_soc_codec *codec, unsigned int reg,
+			     unsigned int value)
+{
+	u16 *cache = codec->reg_cache;
+	u8 data[2];
+	int ret;
+
+	BUG_ON(codec->volatile_register);
+
+	data[0] = (reg << 1) | ((value >> 8) & 0x0001);
+	data[1] = value & 0x00ff;
+
+	if (reg < codec->reg_cache_size)
+		cache[reg] = value;
+	ret = codec->hw_write(codec->control_data, data, 2);
+	if (ret == 2)
+		return 0;
+	if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+
+static struct {
+	int addr_bits;
+	int data_bits;
+	int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
+	unsigned int (*read)(struct snd_soc_codec *, unsigned int);
+} io_types[] = {
+	{ 7, 9, snd_soc_7_9_write, snd_soc_7_9_read },
+};
+
+/**
+ * snd_soc_codec_set_cache_io: Set up standard I/O functions.
+ *
+ * @codec: CODEC to configure.
+ * @type: Type of cache.
+ * @addr_bits: Number of bits of register address data.
+ * @data_bits: Number of bits of data per register.
+ *
+ * Register formats are frequently shared between many I2C and SPI
+ * devices.  In order to promote code reuse the ASoC core provides
+ * some standard implementations of CODEC read and write operations
+ * which can be set up using this function.
+ *
+ * The caller is responsible for allocating and initialising the
+ * actual cache.
+ *
+ * Note that at present this code cannot be used by CODECs with
+ * volatile registers.
+ */
+int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
+			       int addr_bits, int data_bits)
+{
+	int i;
+
+	/* We don't support volatile registers yet - refactoring of
+	 * the hw_read operation will be required to do so. */
+	if (codec->volatile_register) {
+		printk(KERN_ERR "Volatile registers not yet supported\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(io_types); i++)
+		if (io_types[i].addr_bits == addr_bits &&
+		    io_types[i].data_bits == data_bits)
+			break;
+	if (i == ARRAY_SIZE(io_types)) {
+		printk(KERN_ERR
+		       "No I/O functions for %d bit address %d bit data\n",
+		       addr_bits, data_bits);
+		return -EINVAL;
+	}
+
+	codec->write = io_types[i].write;
+	codec->read = io_types[i].read;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);