[PATCH] i2c: New Xicor X1205 RTC driver

New driver for the Xicor X1205 RTC chip.

Signed-off-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 777 insertions, 0 deletions

diff --git a/Documentation/i2c/chips/x1205 b/Documentation/i2c/chips/x1205
new file mode 100644
index 000000000000..09407c991fe5
--- /dev/null
+++ b/Documentation/i2c/chips/x1205
@@ -0,0 +1,38 @@
+Kernel driver x1205
+===================
+
+Supported chips:
+  * Xicor X1205 RTC
+    Prefix: 'x1205'
+    Addresses scanned: none
+    Datasheet: http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
+
+Authors:
+        Karen Spearel <kas11@tampabay.rr.com>,
+        Alessandro Zummo <a.zummo@towertech.it>
+
+Description
+-----------
+
+This module aims to provide complete access to the Xicor X1205 RTC.
+Recently Xicor has merged with Intersil, but the chip is
+still sold under the Xicor brand.
+
+This chip is located at address 0x6f and uses a 2-byte register addressing.
+Two bytes need to be written to read a single register, while most
+other chips just require one and take the second one as the data
+to be written. To prevent corrupting unknown chips, the user must
+explicitely set the probe parameter.
+
+example:
+
+modprobe x1205 probe=0,0x6f
+
+The module supports one more option, hctosys, which is used to set the
+software clock from the x1205. On systems where the x1205 is the
+only hardware rtc, this parameter could be used to achieve a correct
+date/time earlier in the system boot sequence.
+
+example:
+
+modprobe x1205 probe=0,0x6f hctosys=1
diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 6bd44a44cd28..f9fae28f5612 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -126,4 +126,13 @@ config SENSORS_MAX6875
           This driver can also be built as a module.  If so, the module
           will be called max6875.
 
+config RTC_X1205_I2C
+        tristate "Xicor X1205 RTC chip"
+        depends on I2C && EXPERIMENTAL
+        help
+          If you say yes here you get support for the Xicor X1205 RTC chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called x1205.
+
 endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index a876dd42b860..46178b57b1f1 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
 obj-$(CONFIG_SENSORS_RTC8564)   += rtc8564.o
 obj-$(CONFIG_ISP1301_OMAP)      += isp1301_omap.o
 obj-$(CONFIG_TPS65010)          += tps65010.o
+obj-$(CONFIG_RTC_X1205_I2C)     += x1205.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/x1205.c b/drivers/i2c/chips/x1205.c
new file mode 100644
index 000000000000..7da366cdc18c
--- /dev/null
+++ b/drivers/i2c/chips/x1205.c
@@ -0,0 +1,698 @@
+/*
+ *  x1205.c - An i2c driver for the Xicor X1205 RTC
+ *  Copyright 2004 Karen Spearel
+ *  Copyright 2005 Alessandro Zummo
+ *
+ *  please send all reports to:
+ *      kas11 at tampabay dot rr dot com
+ *      a dot zummo at towertech dot it
+ *
+ *  based on the other drivers in this same directory.
+ *
+ *  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 <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/string.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/list.h>
+
+#include <linux/x1205.h>
+
+#define DRV_VERSION "0.9.9"
+
+/* Addresses to scan: none. This chip is located at
+ * 0x6f and uses a two bytes register addressing.
+ * Two bytes need to be written to read a single register,
+ * while most other chips just require one and take the second
+ * one as the data to be written. To prevent corrupting
+ * unknown chips, the user must explicitely set the probe parameter.
+ */
+
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+I2C_CLIENT_MODULE_PARM(hctosys,
+        "Set the system time from the hardware clock upon initialization");
+
+/* offsets into CCR area */
+
+#define CCR_SEC                 0
+#define CCR_MIN                 1
+#define CCR_HOUR                2
+#define CCR_MDAY                3
+#define CCR_MONTH               4
+#define CCR_YEAR                5
+#define CCR_WDAY                6
+#define CCR_Y2K                 7
+
+#define X1205_REG_SR            0x3F    /* status register */
+#define X1205_REG_Y2K           0x37
+#define X1205_REG_DW            0x36
+#define X1205_REG_YR            0x35
+#define X1205_REG_MO            0x34
+#define X1205_REG_DT            0x33
+#define X1205_REG_HR            0x32
+#define X1205_REG_MN            0x31
+#define X1205_REG_SC            0x30
+#define X1205_REG_DTR           0x13
+#define X1205_REG_ATR           0x12
+#define X1205_REG_INT           0x11
+#define X1205_REG_0             0x10
+#define X1205_REG_Y2K1          0x0F
+#define X1205_REG_DWA1          0x0E
+#define X1205_REG_YRA1          0x0D
+#define X1205_REG_MOA1          0x0C
+#define X1205_REG_DTA1          0x0B
+#define X1205_REG_HRA1          0x0A
+#define X1205_REG_MNA1          0x09
+#define X1205_REG_SCA1          0x08
+#define X1205_REG_Y2K0          0x07
+#define X1205_REG_DWA0          0x06
+#define X1205_REG_YRA0          0x05
+#define X1205_REG_MOA0          0x04
+#define X1205_REG_DTA0          0x03
+#define X1205_REG_HRA0          0x02
+#define X1205_REG_MNA0          0x01
+#define X1205_REG_SCA0          0x00
+
+#define X1205_CCR_BASE          0x30    /* Base address of CCR */
+#define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
+
+#define X1205_SR_RTCF           0x01    /* Clock failure */
+#define X1205_SR_WEL            0x02    /* Write Enable Latch */
+#define X1205_SR_RWEL           0x04    /* Register Write Enable */
+
+#define X1205_DTR_DTR0          0x01
+#define X1205_DTR_DTR1          0x02
+#define X1205_DTR_DTR2          0x04
+
+#define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
+
+/* Prototypes */
+static int x1205_attach(struct i2c_adapter *adapter);
+static int x1205_detach(struct i2c_client *client);
+static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
+static int x1205_command(struct i2c_client *client, unsigned int cmd,
+        void *arg);
+
+static struct i2c_driver x1205_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "x1205",
+        .flags          = I2C_DF_NOTIFY,
+        .attach_adapter = &x1205_attach,
+        .detach_client  = &x1205_detach,
+};
+
+struct x1205_data {
+        struct i2c_client client;
+        struct list_head list;
+        unsigned int epoch;
+};
+
+static const unsigned char days_in_mo[] =
+        { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };