rtc: add EM3027 rtc driver
Mike Rapoport [Thu, 26 May 2011 23:25:04 +0000 (16:25 -0700)]
Add support for EM Microelectronic EM3027 RTC chip.

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-em3027.c [new file with mode: 0644]

index 3db52f0..512b40e 100644 (file)
@@ -361,6 +361,15 @@ 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"
index 986f17e..4801a0a 100644 (file)
@@ -44,6 +44,7 @@ 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 (file)
index 0000000..d8e1c25
--- /dev/null
@@ -0,0 +1,161 @@
+/*
+ * An rtc/i2c driver for the EM Microelectronic EM3027
+ * Copyright 2011 CompuLab, Ltd.
+ *
+ * Author: Mike Rapoport <mike@compulab.co.il>
+ *
+ * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * 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@compulab.co.il>");
+MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
+MODULE_LICENSE("GPL");
+
+module_init(em3027_init);
+module_exit(em3027_exit);