[PATCH] i2c driver for Maxim max9485 audio clock generator chip

[Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Signed-off-by: Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/i2c/chips/Kconfig   |    9 ++++
 drivers/i2c/chips/Makefile  |    1 
 drivers/i2c/chips/max9485.c |  106 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/i2c/max9485.h |   38 +++++++++++++++
 4 files changed, 154 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/chips/max9485.c
 create mode 100644 include/linux/i2c/max9485.h

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 1735682..bc2a6d3 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -40,6 +40,15 @@ config AT24
 	  This driver can also be built as a module.  If so, the module
 	  will be called at24.
 
+config MAX9485
+	tristate "Maxim MAX9485 Programmable Audio Clock Generator"
+	help
+	  If you say yes here you get support for Maxim MAX9485 
+	  Programmable Audio Clock Generator.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called max9485.
+
 config SENSORS_EEPROM
 	tristate "EEPROM reader"
 	depends on EXPERIMENTAL
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index ca520fa..1560baf 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -11,6 +11,7 @@
 
 obj-$(CONFIG_DS1682)		+= ds1682.o
 obj-$(CONFIG_AT24)		+= at24.o
+obj-$(CONFIG_MAX9485)		+= max9485.o
 obj-$(CONFIG_SENSORS_EEPROM)	+= eeprom.o
 obj-$(CONFIG_SENSORS_MAX6875)	+= max6875.o
 obj-$(CONFIG_SENSORS_PCA9539)	+= pca9539.o
diff --git a/drivers/i2c/chips/max9485.c b/drivers/i2c/chips/max9485.c
new file mode 100644
index 0000000..65058b4
--- /dev/null
+++ b/drivers/i2c/chips/max9485.c
@@ -0,0 +1,106 @@
+/*
+ * Maxim max9485 Programmable Audio Clock Generator driver
+ *
+ * Written by: Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * Copyright (C) Digispeaker.com
+ *
+ * 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.
+ */
+
+/*
+ * This device is under the control of ALSA and can not be changed from
+ * userspace. The main purpose of this driver is to locate the i2c address
+ * of where the chip is located.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/sysfs.h>
+#include <linux/i2c/max9485.h>
+
+int max9485_set(struct i2c_client *max9485, u8 value)
+{
+	int rc;
+
+	if (!max9485)
+		return -ENODEV;
+
+	rc = i2c_smbus_write_byte(max9485, value);
+	if (rc < 0)
+		return -EIO;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(max9485_set);
+
+/*
+ * Display the only register
+ */
+static ssize_t max9485_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int rc;
+
+	rc = i2c_smbus_read_byte(client);
+	if (rc < 0)
+		return -EIO;
+
+	return sprintf(buf, "0x%02X\n", rc);
+}
+static DEVICE_ATTR(max9485, S_IRUGO, max9485_show, NULL);
+
+/*
+ * Called when a max9485 device is matched with this driver
+ */
+static int max9485_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	if (!i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_READ_BYTE | I2C_FUNC_SMBUS_WRITE_BYTE)) {
+		dev_err(&client->dev, "i2c bus does not support the max9485\n");
+		return -ENODEV;
+	}
+	return sysfs_create_file(&client->dev.kobj, &dev_attr_max9485.attr);
+}
+
+static int max9485_remove(struct i2c_client *client)
+{
+	sysfs_remove_file(&client->dev.kobj, &dev_attr_max9485.attr);
+	return 0;
+}
+
+static const struct i2c_device_id max9485_id[] = {
+	{ "max9485", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max9485_id);
+
+static struct i2c_driver max9485_driver = {
+	.driver = {
+		.name = "max9485",
+	},
+	.probe = max9485_probe,
+	.remove = max9485_remove,
+	.id_table = max9485_id,
+};
+
+static int __init max9485_init(void)
+{
+	return i2c_add_driver(&max9485_driver);
+}
+
+static void __exit max9485_exit(void)
+{
+	i2c_del_driver(&max9485_driver);
+}
+
+MODULE_AUTHOR("Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org");
+MODULE_DESCRIPTION("Maxim MAX9485 Programmable Audio Clock Generator driver");
+MODULE_LICENSE("GPL");
+
+module_init(max9485_init);
+module_exit(max9485_exit);
diff --git a/include/linux/i2c/max9485.h b/include/linux/i2c/max9485.h
new file mode 100644
index 0000000..0c97450
--- /dev/null
+++ b/include/linux/i2c/max9485.h
@@ -0,0 +1,38 @@
+/*
+ * Maxim max9485 Programmable Audio Clock Generator driver
+ *
+ * Written by: Jon Smirl <jonsmirl-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * Copyright (C) Digispeaker.com
+ *
+ * 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 __LINUX_I2C_MAX9485_H
+#define __LINUX_I2C_MAX9485_H
+
+struct i2c_client;
+
+/* Defines for Maxim MAX9485 Audio Clock Generator */
+
+#define MAX9485_MCLK 0x80
+#define MAX9485_CLK_OUT_2 0x40
+#define MAX9485_CLK_OUT_1 0x20
+#define MAX9485_DOUBLED 0x10
+#define MAX9485_SCALE_256 0x0
+#define MAX9485_SCALE_384 0x2
+#define MAX9485_SCALE_768 0x6
+#define MAX9485_FREQUENCY_12 0x0
+#define MAX9485_FREQUENCY_32 0x1
+#define MAX9485_FREQUENCY_441 0x2
+#define MAX9485_FREQUENCY_48 0x3
+
+/* Combinations that minimize jitter */
+#define MAX9485_245760 MAX9485_SCALE_256 | MAX9485_FREQUENCY_48 | MAX9485_DOUBLED
+#define MAX9485_225792 MAX9485_SCALE_256 | MAX9485_FREQUENCY_441 | MAX9485_DOUBLED
+
+int max9485_set(struct i2c_client *max9485, u8 value);
+
+#endif /*  __LINUX_I2C_MAX9485_H */


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