[PATCH] rtc: add EM3027 rtc driver

From: Mike Rapoport
Date: Thu Mar 10 2011 - 06:25:17 EST


Add support for EM Microelectronic EM3027 RTC chip.

Signed-off-by: Mike Rapoport <mike@xxxxxxxxxxxxxx>
---
drivers/rtc/Kconfig | 9 +++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-em3027.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 171 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-em3027.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4941cad..13a6042 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -354,6 +354,15 @@ config RTC_DRV_RX8025
This driver can also be built as a module. If so, the module
will be called rtc-rx8025.

+config RTC_DRV_EM3027
+ tristate "EM Microelectronic EM3027"
+ help
+ If you say yes here you get support for the EM
+ Microelectronic EM3027 RTC chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-em3027.
+
endif # I2C

comment "SPI RTC drivers"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 2afdaf3..d29723f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
obj-$(CONFIG_RTC_DRV_DS3232) += rtc-ds3232.o
obj-$(CONFIG_RTC_DRV_DS3234) += rtc-ds3234.o
obj-$(CONFIG_RTC_DRV_EFI) += rtc-efi.o
+obj-$(CONFIG_RTC_DRV_EM3027) += rtc-em3027.o
obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
obj-$(CONFIG_RTC_DRV_FM3130) += rtc-fm3130.o
obj-$(CONFIG_RTC_DRV_GENERIC) += rtc-generic.o
diff --git a/drivers/rtc/rtc-em3027.c b/drivers/rtc/rtc-em3027.c
new file mode 100644
index 0000000..d8e1c25
--- /dev/null
+++ b/drivers/rtc/rtc-em3027.c
@@ -0,0 +1,161 @@
+/*
+ * An rtc/i2c driver for the EM Microelectronic EM3027
+ * Copyright 2011 CompuLab, Ltd.
+ *
+ * Author: Mike Rapoport <mike@xxxxxxxxxxxxxx>
+ *
+ * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
+ *
+ * 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>
+
+/* Registers */
+#define EM3027_REG_ON_OFF_CTRL 0x00
+#define EM3027_REG_IRQ_CTRL 0x01
+#define EM3027_REG_IRQ_FLAGS 0x02
+#define EM3027_REG_STATUS 0x03
+#define EM3027_REG_RST_CTRL 0x04
+
+#define EM3027_REG_WATCH_SEC 0x08
+#define EM3027_REG_WATCH_MIN 0x09
+#define EM3027_REG_WATCH_HOUR 0x0a
+#define EM3027_REG_WATCH_DATE 0x0b
+#define EM3027_REG_WATCH_DAY 0x0c
+#define EM3027_REG_WATCH_MON 0x0d
+#define EM3027_REG_WATCH_YEAR 0x0e
+
+#define EM3027_REG_ALARM_SEC 0x10
+#define EM3027_REG_ALARM_MIN 0x11
+#define EM3027_REG_ALARM_HOUR 0x12
+#define EM3027_REG_ALARM_DATE 0x13
+#define EM3027_REG_ALARM_DAY 0x14
+#define EM3027_REG_ALARM_MON 0x15
+#define EM3027_REG_ALARM_YEAR 0x16
+
+static struct i2c_driver em3027_driver;
+
+static int em3027_get_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+
+ unsigned char addr = EM3027_REG_WATCH_SEC;
+ unsigned char buf[7];
+
+ struct i2c_msg msgs[] = {
+ {client->addr, 0, 1, &addr}, /* setup read addr */
+ {client->addr, I2C_M_RD, 7, buf}, /* read time/date */
+ };
+
+ /* read time/date registers */
+ if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ tm->tm_sec = bcd2bin(buf[0]);
+ tm->tm_min = bcd2bin(buf[1]);
+ tm->tm_hour = bcd2bin(buf[2]);
+ tm->tm_mday = bcd2bin(buf[3]);
+ tm->tm_wday = bcd2bin(buf[4]);
+ tm->tm_mon = bcd2bin(buf[5]);
+ tm->tm_year = bcd2bin(buf[6]) + 100;
+
+ return 0;
+}
+
+static int em3027_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char buf[8];
+
+ struct i2c_msg msg = {
+ client->addr, 0, 8, buf, /* write time/date */
+ };
+
+ buf[0] = EM3027_REG_WATCH_SEC;
+ buf[1] = bin2bcd(tm->tm_sec);
+ buf[2] = bin2bcd(tm->tm_min);
+ buf[3] = bin2bcd(tm->tm_hour);
+ buf[4] = bin2bcd(tm->tm_mday);
+ buf[5] = bin2bcd(tm->tm_wday);
+ buf[6] = bin2bcd(tm->tm_mon);
+ buf[7] = bin2bcd(tm->tm_year % 100);
+
+ /* write time/date registers */
+ if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
+ dev_err(&client->dev, "%s: write error\n", __func__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static const struct rtc_class_ops em3027_rtc_ops = {
+ .read_time = em3027_get_time,
+ .set_time = em3027_set_time,
+};
+
+static int em3027_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct rtc_device *rtc;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ rtc = rtc_device_register(em3027_driver.driver.name, &client->dev,
+ &em3027_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ i2c_set_clientdata(client, rtc);
+
+ return 0;
+}
+
+static int em3027_remove(struct i2c_client *client)
+{
+ struct rtc_device *rtc = i2c_get_clientdata(client);
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ return 0;
+}
+
+static struct i2c_device_id em3027_id[] = {
+ { "em3027", 0 },
+ { }
+};
+
+static struct i2c_driver em3027_driver = {
+ .driver = {
+ .name = "rtc-em3027",
+ },
+ .probe = &em3027_probe,
+ .remove = &em3027_remove,
+ .id_table = em3027_id,
+};
+
+static int __init em3027_init(void)
+{
+ return i2c_add_driver(&em3027_driver);
+}
+
+static void __exit em3027_exit(void)
+{
+ i2c_del_driver(&em3027_driver);
+}
+
+MODULE_AUTHOR("Mike Rapoport <mike@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
+MODULE_LICENSE("GPL");
+
+module_init(em3027_init);
+module_exit(em3027_exit);
--
1.7.3.1

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