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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * An rtc/i2c driver for the EM Microelectronic EM30274 * Copyright 2011 CompuLab, Ltd.5 *6 * Author: Mike Rapoport <mike@compulab.co.il>7 *8 * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>9 */10 11#include <linux/i2c.h>12#include <linux/rtc.h>13#include <linux/bcd.h>14#include <linux/module.h>15#include <linux/of.h>16 17/* Registers */18#define EM3027_REG_ON_OFF_CTRL 0x0019#define EM3027_REG_IRQ_CTRL 0x0120#define EM3027_REG_IRQ_FLAGS 0x0221#define EM3027_REG_STATUS 0x0322#define EM3027_REG_RST_CTRL 0x0423 24#define EM3027_REG_WATCH_SEC 0x0825#define EM3027_REG_WATCH_MIN 0x0926#define EM3027_REG_WATCH_HOUR 0x0a27#define EM3027_REG_WATCH_DATE 0x0b28#define EM3027_REG_WATCH_DAY 0x0c29#define EM3027_REG_WATCH_MON 0x0d30#define EM3027_REG_WATCH_YEAR 0x0e31 32#define EM3027_REG_ALARM_SEC 0x1033#define EM3027_REG_ALARM_MIN 0x1134#define EM3027_REG_ALARM_HOUR 0x1235#define EM3027_REG_ALARM_DATE 0x1336#define EM3027_REG_ALARM_DAY 0x1437#define EM3027_REG_ALARM_MON 0x1538#define EM3027_REG_ALARM_YEAR 0x1639 40static struct i2c_driver em3027_driver;41 42static int em3027_get_time(struct device *dev, struct rtc_time *tm)43{44 struct i2c_client *client = to_i2c_client(dev);45 46 unsigned char addr = EM3027_REG_WATCH_SEC;47 unsigned char buf[7];48 49 struct i2c_msg msgs[] = {50 {/* setup read addr */51 .addr = client->addr,52 .len = 1,53 .buf = &addr54 },55 {/* read time/date */56 .addr = client->addr,57 .flags = I2C_M_RD,58 .len = 7,59 .buf = buf60 },61 };62 63 /* read time/date registers */64 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {65 dev_err(&client->dev, "%s: read error\n", __func__);66 return -EIO;67 }68 69 tm->tm_sec = bcd2bin(buf[0]);70 tm->tm_min = bcd2bin(buf[1]);71 tm->tm_hour = bcd2bin(buf[2]);72 tm->tm_mday = bcd2bin(buf[3]);73 tm->tm_wday = bcd2bin(buf[4]);74 tm->tm_mon = bcd2bin(buf[5]) - 1;75 tm->tm_year = bcd2bin(buf[6]) + 100;76 77 return 0;78}79 80static int em3027_set_time(struct device *dev, struct rtc_time *tm)81{82 struct i2c_client *client = to_i2c_client(dev);83 unsigned char buf[8];84 85 struct i2c_msg msg = {86 .addr = client->addr,87 .len = 8,88 .buf = buf, /* write time/date */89 };90 91 buf[0] = EM3027_REG_WATCH_SEC;92 buf[1] = bin2bcd(tm->tm_sec);93 buf[2] = bin2bcd(tm->tm_min);94 buf[3] = bin2bcd(tm->tm_hour);95 buf[4] = bin2bcd(tm->tm_mday);96 buf[5] = bin2bcd(tm->tm_wday);97 buf[6] = bin2bcd(tm->tm_mon + 1);98 buf[7] = bin2bcd(tm->tm_year % 100);99 100 /* write time/date registers */101 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {102 dev_err(&client->dev, "%s: write error\n", __func__);103 return -EIO;104 }105 106 return 0;107}108 109static const struct rtc_class_ops em3027_rtc_ops = {110 .read_time = em3027_get_time,111 .set_time = em3027_set_time,112};113 114static int em3027_probe(struct i2c_client *client)115{116 struct rtc_device *rtc;117 118 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))119 return -ENODEV;120 121 rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,122 &em3027_rtc_ops, THIS_MODULE);123 if (IS_ERR(rtc))124 return PTR_ERR(rtc);125 126 i2c_set_clientdata(client, rtc);127 128 return 0;129}130 131static const struct i2c_device_id em3027_id[] = {132 { "em3027" },133 { }134};135MODULE_DEVICE_TABLE(i2c, em3027_id);136 137#ifdef CONFIG_OF138static const struct of_device_id em3027_of_match[] = {139 { .compatible = "emmicro,em3027", },140 {}141};142MODULE_DEVICE_TABLE(of, em3027_of_match);143#endif144 145static struct i2c_driver em3027_driver = {146 .driver = {147 .name = "rtc-em3027",148 .of_match_table = of_match_ptr(em3027_of_match),149 },150 .probe = em3027_probe,151 .id_table = em3027_id,152};153 154module_i2c_driver(em3027_driver);155 156MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");157MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");158MODULE_LICENSE("GPL");159