Driver for the Dallas/Maxim DS1672 chip, found
on the Loft (http://www.giantshoulderinc.com) .
Signed-off-by: Alessandro Zummo <[email protected]>
--
drivers/rtc/Kconfig | 10 +
drivers/rtc/Makefile | 1
drivers/rtc/rtc-ds1672.c | 266 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 277 insertions(+)
--- linux-nslu2.orig/drivers/rtc/Kconfig 2006-01-08 18:44:16.000000000 +0100
+++ linux-nslu2/drivers/rtc/Kconfig 2006-01-08 18:44:16.000000000 +0100
@@ -65,6 +65,16 @@ 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
--- linux-nslu2.orig/drivers/rtc/Makefile 2006-01-08 18:44:16.000000000 +0100
+++ linux-nslu2/drivers/rtc/Makefile 2006-01-08 18:44:16.000000000 +0100
@@ -11,4 +11,5 @@ 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
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-nslu2/drivers/rtc/rtc-ds1672.c 2006-01-08 18:44:16.000000000 +0100
@@ -0,0 +1,266 @@
+/*
+ * 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 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/i2c.h>
+#include <linux/rtc.h>
+
+#define DRV_VERSION "0.1"
+
+/* Addresses to scan: none. This chip cannot be detected. */
+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");
+
+/* 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 buf[4];
+
+ 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_hctosys(struct i2c_client *client)
+{
+ int err;
+ struct rtc_time tm;
+ struct timespec tv;
+
+ if ((err = ds1672_get_datetime(client, &tm)) != 0)
+ return err;
+
+ /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+ * whether it stores the most close value or the value with partial
+ * seconds truncated. However, it is important that we use it to store
+ * the truncated value. This is because otherwise it is necessary,
+ * in an rtc sync function, to read both xtime.tv_sec and
+ * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+ * of >32bits is not possible. So storing the most close value would
+ * slow down the sync API. So here we have the truncated value and
+ * the best guess is to add 0.5s.
+ */
+
+ tv.tv_nsec = NSEC_PER_SEC >> 1;
+
+ rtc_tm_to_time(&tm, &tv.tv_sec);
+
+ do_settimeofday(&tv);
+
+ dev_info(&client->dev,
+ "setting the system clock to %d-%02d-%02d %02d:%02d:%02d\n",
+ tm.tm_year + 1900, tm.tm_mon + 1,
+ tm.tm_mday, tm.tm_hour, tm.tm_min,
+ tm.tm_sec);
+
+ return 0;
+}
+
+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 = {
+ .owner = THIS_MODULE,
+ .name = "ds1672",
+ .flags = I2C_DF_NOTIFY,
+ .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.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.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);
+
+ /* If requested, set the system time */
+ if (hctosys) {
+ if ((err = ds1672_hctosys(client)) < 0)
+ dev_err(&client->dev,
+ "unable to set the system clock\n");
+ }
+
+ 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 <[email protected]>");
+MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(ds1672_init);
+module_exit(ds1672_exit);
--