[PATCH] RTC subsystem: RS5C372 driver

RTC class aware driver for the Ricoh RS5C372 chip used, among others, on the
Synology DS101.

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, 305 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 0309fb368758..609f55593459 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -107,6 +107,16 @@ config RTC_DRV_PCF8563
           This driver can also be built as a module. If so, the module
           will be called rtc-pcf8563.
 
+config RTC_DRV_RS5C372
+        tristate "Ricoh RS5C372A/B"
+        depends on RTC_CLASS && I2C
+        help
+          If you say yes here you get support for the
+          Ricoh RS5C372A and RS5C372B RTC chips.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-rs5c372.
+
 config RTC_DRV_TEST
         tristate "Test driver/device"
         depends on RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index bdf7e491d5ac..d2b4b1735598 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -15,4 +15,5 @@ obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
 obj-$(CONFIG_RTC_DRV_TEST)      += rtc-test.o
 obj-$(CONFIG_RTC_DRV_DS1672)    += rtc-ds1672.o
 obj-$(CONFIG_RTC_DRV_PCF8563)   += rtc-pcf8563.o
+obj-$(CONFIG_RTC_DRV_RS5C372)   += rtc-rs5c372.o
 
diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
new file mode 100644
index 000000000000..396c8681f66c
--- /dev/null
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -0,0 +1,294 @@
+/*
+ * An I2C driver for the Ricoh RS5C372 RTC
+ *
+ * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
+ * Copyright (C) 2006 Tower Technologies
+ *
+ * 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/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+
+#define DRV_VERSION "0.2"
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { /* 0x32,*/ I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+
+#define RS5C372_REG_SECS        0
+#define RS5C372_REG_MINS        1
+#define RS5C372_REG_HOURS       2
+#define RS5C372_REG_WDAY        3
+#define RS5C372_REG_DAY         4
+#define RS5C372_REG_MONTH       5
+#define RS5C372_REG_YEAR        6
+#define RS5C372_REG_TRIM        7
+
+#define RS5C372_TRIM_XSL        0x80
+#define RS5C372_TRIM_MASK       0x7F
+
+#define RS5C372_REG_BASE        0
+
+static int rs5c372_attach(struct i2c_adapter *adapter);
+static int rs5c372_detach(struct i2c_client *client);
+static int rs5c372_probe(struct i2c_adapter *adapter, int address, int kind);
+
+static struct i2c_driver rs5c372_driver = {
+        .driver         = {
+                .name   = "rs5c372",
+        },
+        .attach_adapter = &rs5c372_attach,
+        .detach_client  = &rs5c372_detach,
+};
+
+static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+        unsigned char buf[7] = { RS5C372_REG_BASE };
+
+        /* this implements the 1st reading method, according
+         * to the datasheet. buf[0] is initialized with
+         * address ptr and transmission format register.
+         */
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 1, buf },
+                { client->addr, I2C_M_RD, 7, buf },
+        };
+
+        if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        tm->tm_sec = BCD2BIN(buf[RS5C372_REG_SECS] & 0x7f);
+        tm->tm_min = BCD2BIN(buf[RS5C372_REG_MINS] & 0x7f);
+        tm->tm_hour = BCD2BIN(buf[RS5C372_REG_HOURS] & 0x3f);
+        tm->tm_wday = BCD2BIN(buf[RS5C372_REG_WDAY] & 0x07);
+        tm->tm_mday = BCD2BIN(buf[RS5C372_REG_DAY] & 0x3f);
+
+        /* tm->tm_mon is zero-based */
+        tm->tm_mon = BCD2BIN(buf[RS5C372_REG_MONTH] & 0x1f) - 1;
+
+        /* year is 1900 + tm->tm_year */
+        tm->tm_year = BCD2BIN(buf[RS5C372_REG_YEAR]) + 100;
+
+        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 rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+        unsigned char buf[8] = { RS5C372_REG_BASE };
+
+        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);
+
+        buf[1] = BIN2BCD(tm->tm_sec);
+        buf[2] = BIN2BCD(tm->tm_min);
+        buf[3] = BIN2BCD(tm->tm_hour);
+        buf[4] = BIN2BCD(tm->tm_wday);
+        buf[5] = BIN2BCD(tm->tm_mday);
+        buf[6] = BIN2BCD(tm->tm_mon + 1);
+        buf[7] = BIN2BCD(tm->tm_year - 100);
+
+        if ((i2c_master_send(client, buf, 8)) != 8) {
+                dev_err(&client->dev, "%s: write error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        return 0;
+}
+
+static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
+{
+        unsigned char buf = RS5C372_REG_TRIM;
+
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 1, &buf },
+                { client->addr, I2C_M_RD, 1, &buf },
+        };
+
+        if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        dev_dbg(&client->dev, "%s: raw trim=%x\n", __FUNCTION__, trim);
+
+        if (osc)
+                *osc = (buf & RS5C372_TRIM_XSL) ? 32000 : 32768;
+
+        if (trim)
+                *trim = buf & RS5C372_TRIM_MASK;
+
+        return 0;
+}
+
+static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        return rs5c372_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        return rs5c372_set_datetime(to_i2c_client(dev), tm);
+}
+
+static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+        int err, osc, trim;
+
+        seq_printf(seq, "24hr\t\t: yes\n");
+
+        if ((err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim)) == 0) {
+                seq_printf(seq, "%d.%03d KHz\n", osc / 1000, osc % 1000);
+                seq_printf(seq, "trim\t: %d\n", trim);
+        }
+
+        return 0;
+}
+
+static struct rtc_class_ops rs5c372_rtc_ops = {
+        .proc           = rs5c372_rtc_proc,
+        .read_time      = rs5c372_rtc_read_time,
+        .set_time       = rs5c372_rtc_set_time,
+};
+
+static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        int trim;
+
+        if (rs5c372_get_trim(to_i2c_client(dev), NULL, &trim) == 0)
+                return sprintf(buf, "0x%2x\n", trim);
+
+        return 0;
+}
+static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
+
+static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        int osc;
+
+        if (rs5c372_get_trim(to_i2c_client(dev), &osc, NULL) == 0)
+                return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
+
+        return 0;
+}
+static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
+
+static int rs5c372_attach(struct i2c_adapter *adapter)
+{
+        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+        return i2c_probe(adapter, &addr_data, rs5c372_probe);
+}
+
+static int rs5c372_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 = &rs5c372_driver;
+        client->adapter = adapter;
+
+        strlcpy(client->name, rs5c372_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(rs5c372_driver.driver.name, &client->dev,
+                                &rs5c372_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);
+
+        device_create_file(&client->dev, &dev_attr_trim);
+        device_create_file(&client->dev, &dev_attr_osc);
+
+        return 0;
+
+exit_detach:
+        i2c_detach_client(client);
+
+exit_kfree:
+        kfree(client);
+
+exit:
+        return err;
+}
+
+static int rs5c372_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 __init int rs5c372_init(void)
+{
+        return i2c_add_driver(&rs5c372_driver);
+}
+
+static __exit void rs5c372_exit(void)
+{
+        i2c_del_driver(&rs5c372_driver);
+}
+
+module_init(rs5c372_init);
+module_exit(rs5c372_exit);
+
+MODULE_AUTHOR(
+                "Pavel Mironchik <pmironchik@optifacio.net>, "
+                "Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);