diff options
Diffstat (limited to 'drivers/rtc/rtc-em3027.c')
| -rw-r--r-- | drivers/rtc/rtc-em3027.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-em3027.c b/drivers/rtc/rtc-em3027.c new file mode 100644 index 000000000..53f9f9391 --- /dev/null +++ b/drivers/rtc/rtc-em3027.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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> + */ + +#include <linux/i2c.h> +#include <linux/rtc.h> +#include <linux/bcd.h> +#include <linux/module.h> +#include <linux/of.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[] = { + {/* setup read addr */ + .addr = client->addr, + .len = 1, + .buf = &addr + }, + {/* read time/date */ + .addr = client->addr, + .flags = I2C_M_RD, + .len = 7, + .buf = buf + }, + }; + + /* 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]) - 1; + 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 = { + .addr = client->addr, + .len = 8, + .buf = 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 + 1); + 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) +{ + struct rtc_device *rtc; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name, + &em3027_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + i2c_set_clientdata(client, rtc); + + return 0; +} + +static const struct i2c_device_id em3027_id[] = { + { "em3027", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, em3027_id); + +#ifdef CONFIG_OF +static const struct of_device_id em3027_of_match[] = { + { .compatible = "emmicro,em3027", }, + {} +}; +MODULE_DEVICE_TABLE(of, em3027_of_match); +#endif + +static struct i2c_driver em3027_driver = { + .driver = { + .name = "rtc-em3027", + .of_match_table = of_match_ptr(em3027_of_match), + }, + .probe_new = em3027_probe, + .id_table = em3027_id, +}; + +module_i2c_driver(em3027_driver); + +MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>"); +MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver"); +MODULE_LICENSE("GPL"); |