[PATCH] I2C: m41t00: Add support for the ST M41T81 and M41T85

This patch adds support for the ST m41t81 and m41t85 i2c rtc chips
to the existing m41t00 driver.

Since there is no way to reliably determine what type of rtc chip
is in use, the chip type is passed in via platform_data.  The i2c
address and square wave frequency are passed in via platform_data
as well.  To accommodate the use of platform_data, a new header
file include/linux/m41t00.h has been added.

The m41t81 and m41t85 chips halt the updating of their time registers
while they are being accessed.  They resume when a stop condition
exists on the i2c bus or when non-time related regs are accessed.
To make the best use of that facility and to make more efficient
use of the i2c bus, this patch replaces multiple i2c_smbus_xxx calls
with a single i2c_transfer call.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 50 insertions, 0 deletions

diff --git a/include/linux/m41t00.h b/include/linux/m41t00.h
new file mode 100644
index 000000000000..b423360ca38e
--- /dev/null
+++ b/include/linux/m41t00.h
@@ -0,0 +1,50 @@
+/*
+ * Definitions for the ST M41T00 family of i2c rtc chips.
+ *
+ * Author: Mark A. Greer <mgreer@mvista.com>
+ *
+ * 2005, 2006 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#ifndef _M41T00_H
+#define _M41T00_H
+
+#define M41T00_DRV_NAME         "m41t00"
+#define M41T00_I2C_ADDR         0x68
+
+#define M41T00_TYPE_M41T00      0
+#define M41T00_TYPE_M41T81      81
+#define M41T00_TYPE_M41T85      85
+
+struct m41t00_platform_data {
+        u8      type;
+        u8      i2c_addr;
+        u8      sqw_freq;
+};
+
+/* SQW output disabled, this is default value by power on */
+#define M41T00_SQW_DISABLE      (0)
+
+#define M41T00_SQW_32KHZ        (1<<4)          /* 32.768 KHz */
+#define M41T00_SQW_8KHZ         (2<<4)          /* 8.192 KHz */
+#define M41T00_SQW_4KHZ         (3<<4)          /* 4.096 KHz */
+#define M41T00_SQW_2KHZ         (4<<4)          /* 2.048 KHz */
+#define M41T00_SQW_1KHZ         (5<<4)          /* 1.024 KHz */
+#define M41T00_SQW_512HZ        (6<<4)          /* 512 Hz */
+#define M41T00_SQW_256HZ        (7<<4)          /* 256 Hz */
+#define M41T00_SQW_128HZ        (8<<4)          /* 128 Hz */
+#define M41T00_SQW_64HZ         (9<<4)          /* 64 Hz */
+#define M41T00_SQW_32HZ         (10<<4)         /* 32 Hz */
+#define M41T00_SQW_16HZ         (11<<4)         /* 16 Hz */
+#define M41T00_SQW_8HZ          (12<<4)         /* 8 Hz */
+#define M41T00_SQW_4HZ          (13<<4)         /* 4 Hz */
+#define M41T00_SQW_2HZ          (14<<4)         /* 2 Hz */
+#define M41T00_SQW_1HZ          (15<<4)         /* 1 Hz */
+
+extern ulong m41t00_get_rtc_time(void);
+extern int m41t00_set_rtc_time(ulong nowtime);
+
+#endif /* _M41T00_H */