[PATCH] RTC subsystem: DS1672 driver

Driver for the Dallas/Maxim DS1672 chip, found on the Loft
(http://www.giantshoulderinc.com).

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 244 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 7eb1368d04f6..de3352658654 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -86,6 +86,16 @@ config RTC_DRV_X1205
           This driver can also be built as a module. If so, the module
           will be called rtc-x1205.
 
+config RTC_DRV_DS1672
+        tristate "Dallas/Maxim DS1672"
+        depends on RTC_CLASS && I2C
+        help
+          If you say yes here you get support for the
+          Dallas/Maxim DS1672 timekeeping chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-ds1672.
+
 config RTC_DRV_TEST
         tristate "Test driver/device"
         depends on RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index d5ea0ed81905..f3fd5b0cd735 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -13,4 +13,5 @@ obj-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o
 
 obj-$(CONFIG_RTC_DRV_X1205)     += rtc-x1205.o
 obj-$(CONFIG_RTC_DRV_TEST)      += rtc-test.o
+obj-$(CONFIG_RTC_DRV_DS1672)    += rtc-ds1672.o
 
diff --git a/drivers/rtc/rtc-ds1672.c b/drivers/rtc/rtc-ds1672.c
new file mode 100644
index 000000000000..358695a416f3
--- /dev/null
+++ b/drivers/rtc/rtc-ds1672.c
@@ -0,0 +1,233 @@
+/*
+ * An rtc/i2c driver for the Dallas DS1672
+ * Copyright 2005 Alessandro Zummo
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+
+#define DRV_VERSION "0.2"
+
+/* Addresses to scan: none. This chip cannot be detected. */
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+/* Registers */
+
+#define DS1672_REG_CNT_BASE     0
+#define DS1672_REG_CONTROL      4
+#define DS1672_REG_TRICKLE      5
+
+
+/* Prototypes */
+static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind);
+
+/*
+ * In the routines that deal directly with the ds1672 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
+ * Epoch is initialized as 2000. Time is set to UTC.
+ */
+static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+        unsigned long time;
+        unsigned char addr = DS1672_REG_CNT_BASE;
+        unsigned char buf[4];
+
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 1, &addr },          /* setup read ptr */
+                { client->addr, I2C_M_RD, 4, buf },     /* read date */
+        };
+
+        /* read date registers */
+        if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        dev_dbg(&client->dev,
+                "%s: raw read data - counters=%02x,%02x,%02x,%02x\n"
+                __FUNCTION__,
+                buf[0], buf[1], buf[2], buf[3]);
+
+        time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+
+        rtc_time_to_tm(time, tm);
+
+        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
+                "mday=%d, mon=%d, year=%d, wday=%d\n",
+                __FUNCTION__,
+                tm->tm_sec, tm->tm_min, tm->tm_hour,
+                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+        return 0;
+}
+
+static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
+{
+        int xfer;
+        unsigned char buf[5];
+
+        buf[0] = DS1672_REG_CNT_BASE;
+        buf[1] = secs & 0x000000FF;
+        buf[2] = (secs & 0x0000FF00) >> 8;
+        buf[3] = (secs & 0x00FF0000) >> 16;
+        buf[4] = (secs & 0xFF000000) >> 24;
+
+        xfer = i2c_master_send(client, buf, 5);
+        if (xfer != 5) {
+                dev_err(&client->dev, "%s: send: %d\n", __FUNCTION__, xfer);
+                return -EIO;
+        }
+
+        return 0;
+}
+
+static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+        unsigned long secs;
+
+        dev_dbg(&client->dev,
+                "%s: secs=%d, mins=%d, hours=%d, ",
+                "mday=%d, mon=%d, year=%d, wday=%d\n",
+                __FUNCTION__,
+                tm->tm_sec, tm->tm_min, tm->tm_hour,
+                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+        rtc_tm_to_time(tm, &secs);
+
+        return ds1672_set_mmss(client, secs);
+}
+
+static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        return ds1672_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        return ds1672_set_datetime(to_i2c_client(dev), tm);
+}
+
+static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
+{
+        return ds1672_set_mmss(to_i2c_client(dev), secs);
+}
+
+static struct rtc_class_ops ds1672_rtc_ops = {
+        .read_time      = ds1672_rtc_read_time,
+        .set_time       = ds1672_rtc_set_time,
+        .set_mmss       = ds1672_rtc_set_mmss,
+};
+
+static int ds1672_attach(struct i2c_adapter *adapter)
+{
+        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+        return i2c_probe(adapter, &addr_data, ds1672_probe);
+}
+
+static int ds1672_detach(struct i2c_client *client)
+{
+        int err;
+        struct rtc_device *rtc = i2c_get_clientdata(client);
+
+        dev_dbg(&client->dev, "%s\n", __FUNCTION__);
+
+        if (rtc)
+                rtc_device_unregister(rtc);
+
+        if ((err = i2c_detach_client(client)))
+                return err;
+
+        kfree(client);
+
+        return 0;
+}
+
+static struct i2c_driver ds1672_driver = {
+        .driver         = {
+                .name   = "ds1672",
+        },
+        .id             = I2C_DRIVERID_DS1672,
+        .attach_adapter = &ds1672_attach,
+        .detach_client  = &ds1672_detach,
+};
+
+static int ds1672_probe(struct i2c_adapter *adapter, int address, int kind)
+{
+        int err = 0;
+        struct i2c_client *client;
+        struct rtc_device *rtc;
+
+        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+                err = -ENODEV;
+                goto exit;
+        }
+
+        if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
+                err = -ENOMEM;
+                goto exit;
+        }
+
+        /* I2C client */
+        client->addr = address;
+        client->driver = &ds1672_driver;
+        client->adapter = adapter;
+
+        strlcpy(client->name, ds1672_driver.driver.name, I2C_NAME_SIZE);
+
+        /* Inform the i2c layer */
+        if ((err = i2c_attach_client(client)))
+                goto exit_kfree;
+
+        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+        rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev,
+                                &ds1672_rtc_ops, THIS_MODULE);
+
+        if (IS_ERR(rtc)) {
+                err = PTR_ERR(rtc);
+                dev_err(&client->dev,
+                        "unable to register the class device\n");
+                goto exit_detach;
+        }
+
+        i2c_set_clientdata(client, rtc);
+
+        return 0;
+
+exit_detach:
+        i2c_detach_client(client);
+
+exit_kfree:
+        kfree(client);
+
+exit:
+        return err;
+}
+
+static int __init ds1672_init(void)
+{
+        return i2c_add_driver(&ds1672_driver);
+}
+
+static void __exit ds1672_exit(void)
+{
+        i2c_del_driver(&ds1672_driver);
+}
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(ds1672_init);
+module_exit(ds1672_exit);