159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* An rtc/i2c driver for the EM Microelectronic EM3027
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* Copyright 2011 CompuLab, Ltd.
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*
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* Author: Mike Rapoport <mike@compulab.co.il>
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*
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* Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
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*/
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#include <linux/i2c.h>
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#include <linux/rtc.h>
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#include <linux/bcd.h>
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#include <linux/module.h>
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#include <linux/of.h>
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/* Registers */
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#define EM3027_REG_ON_OFF_CTRL 0x00
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#define EM3027_REG_IRQ_CTRL 0x01
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#define EM3027_REG_IRQ_FLAGS 0x02
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#define EM3027_REG_STATUS 0x03
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#define EM3027_REG_RST_CTRL 0x04
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#define EM3027_REG_WATCH_SEC 0x08
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#define EM3027_REG_WATCH_MIN 0x09
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#define EM3027_REG_WATCH_HOUR 0x0a
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#define EM3027_REG_WATCH_DATE 0x0b
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#define EM3027_REG_WATCH_DAY 0x0c
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#define EM3027_REG_WATCH_MON 0x0d
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#define EM3027_REG_WATCH_YEAR 0x0e
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#define EM3027_REG_ALARM_SEC 0x10
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#define EM3027_REG_ALARM_MIN 0x11
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#define EM3027_REG_ALARM_HOUR 0x12
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#define EM3027_REG_ALARM_DATE 0x13
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#define EM3027_REG_ALARM_DAY 0x14
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#define EM3027_REG_ALARM_MON 0x15
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#define EM3027_REG_ALARM_YEAR 0x16
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static struct i2c_driver em3027_driver;
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static int em3027_get_time(struct device *dev, struct rtc_time *tm)
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{
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struct i2c_client *client = to_i2c_client(dev);
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unsigned char addr = EM3027_REG_WATCH_SEC;
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unsigned char buf[7];
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struct i2c_msg msgs[] = {
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{/* setup read addr */
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.addr = client->addr,
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.len = 1,
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.buf = &addr
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},
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{/* read time/date */
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = 7,
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.buf = buf
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},
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};
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/* read time/date registers */
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if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
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dev_err(&client->dev, "%s: read error\n", __func__);
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return -EIO;
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}
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tm->tm_sec = bcd2bin(buf[0]);
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tm->tm_min = bcd2bin(buf[1]);
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tm->tm_hour = bcd2bin(buf[2]);
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tm->tm_mday = bcd2bin(buf[3]);
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tm->tm_wday = bcd2bin(buf[4]);
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tm->tm_mon = bcd2bin(buf[5]) - 1;
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tm->tm_year = bcd2bin(buf[6]) + 100;
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return 0;
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}
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static int em3027_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct i2c_client *client = to_i2c_client(dev);
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unsigned char buf[8];
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struct i2c_msg msg = {
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.addr = client->addr,
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.len = 8,
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.buf = buf, /* write time/date */
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};
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buf[0] = EM3027_REG_WATCH_SEC;
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buf[1] = bin2bcd(tm->tm_sec);
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buf[2] = bin2bcd(tm->tm_min);
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buf[3] = bin2bcd(tm->tm_hour);
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buf[4] = bin2bcd(tm->tm_mday);
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buf[5] = bin2bcd(tm->tm_wday);
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buf[6] = bin2bcd(tm->tm_mon + 1);
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buf[7] = bin2bcd(tm->tm_year % 100);
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/* write time/date registers */
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if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
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dev_err(&client->dev, "%s: write error\n", __func__);
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return -EIO;
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}
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return 0;
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}
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static const struct rtc_class_ops em3027_rtc_ops = {
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.read_time = em3027_get_time,
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.set_time = em3027_set_time,
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};
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static int em3027_probe(struct i2c_client *client)
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{
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struct rtc_device *rtc;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
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&em3027_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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i2c_set_clientdata(client, rtc);
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return 0;
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}
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static const struct i2c_device_id em3027_id[] = {
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{ "em3027", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, em3027_id);
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#ifdef CONFIG_OF
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static const struct of_device_id em3027_of_match[] = {
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{ .compatible = "emmicro,em3027", },
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{}
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};
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MODULE_DEVICE_TABLE(of, em3027_of_match);
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#endif
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static struct i2c_driver em3027_driver = {
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.driver = {
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.name = "rtc-em3027",
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.of_match_table = of_match_ptr(em3027_of_match),
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},
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.probe_new = em3027_probe,
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.id_table = em3027_id,
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};
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module_i2c_driver(em3027_driver);
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MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
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MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
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MODULE_LICENSE("GPL");
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