diff options
Diffstat (limited to 'drivers/rtc/rtc-em3027.c')
| -rw-r--r-- | drivers/rtc/rtc-em3027.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-em3027.c b/drivers/rtc/rtc-em3027.c new file mode 100644 index 000000000000..d8e1c2578553 --- /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@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); |