ASoC: ad193x: Split SPI and I2C code into different modules

There are a few known (minor) problems with having the support code for both I2C
and SPI in the same module:
    * We need to be extra careful to make sure to not build the driver into the
      kernel if one of the subsystems is build as a module (Currently only I2C
      can be build as a module).
    * The module init path error handling is rather ugly. E.g. what should be
      done if either the SPI or the I2C driver fails to register? Most drivers
      that implement SPI and I2C in the same module currently fallback to
      undefined behavior in that case. Splitting the the driver into two
      modules, one for each bus, allows the registration of the other bus driver
      to continue without problems if one of them fails.

This patch splits the AD193X driver into 3 modules. One core module that
implements the device logic, but is independent of the bus method used. And one
module for SPI and I2C each that registers the drivers and sets up the regmap
struct for the bus.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/sound/soc/codecs/ad193x-i2c.c b/sound/soc/codecs/ad193x-i2c.c
new file mode 100644
index 000000000000..df3a1a415825
--- /dev/null
+++ b/sound/soc/codecs/ad193x-i2c.c
@@ -0,0 +1,54 @@
+/*
+ * AD1936/AD1937 audio driver
+ *
+ * Copyright 2014 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+
+#include <sound/soc.h>
+
+#include "ad193x.h"
+
+static const struct i2c_device_id ad193x_id[] = {
+	{ "ad1936", 0 },
+	{ "ad1937", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ad193x_id);
+
+static int ad193x_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct regmap_config config;
+
+	config = ad193x_regmap_config;
+	config.val_bits = 8;
+	config.reg_bits = 8;
+
+	return ad193x_probe(&client->dev, devm_regmap_init_i2c(client, &config));
+}
+
+static int ad193x_i2c_remove(struct i2c_client *client)
+{
+	snd_soc_unregister_codec(&client->dev);
+	return 0;
+}
+
+static struct i2c_driver ad193x_i2c_driver = {
+	.driver = {
+		.name = "ad193x",
+	},
+	.probe    = ad193x_i2c_probe,
+	.remove   = ad193x_i2c_remove,
+	.id_table = ad193x_id,
+};
+module_i2c_driver(ad193x_i2c_driver);
+
+MODULE_DESCRIPTION("ASoC AD1936/AD1937 audio CODEC driver");
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_LICENSE("GPL");