1 /* 2 * An rtc/i2c driver for the EM Microelectronic EM3027 3 * Copyright 2011 CompuLab, Ltd. 4 * 5 * Author: Mike Rapoport <mike@compulab.co.il> 6 * 7 * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/i2c.h> 15 #include <linux/rtc.h> 16 #include <linux/bcd.h> 17 #include <linux/module.h> 18 19 /* Registers */ 20 #define EM3027_REG_ON_OFF_CTRL 0x00 21 #define EM3027_REG_IRQ_CTRL 0x01 22 #define EM3027_REG_IRQ_FLAGS 0x02 23 #define EM3027_REG_STATUS 0x03 24 #define EM3027_REG_RST_CTRL 0x04 25 26 #define EM3027_REG_WATCH_SEC 0x08 27 #define EM3027_REG_WATCH_MIN 0x09 28 #define EM3027_REG_WATCH_HOUR 0x0a 29 #define EM3027_REG_WATCH_DATE 0x0b 30 #define EM3027_REG_WATCH_DAY 0x0c 31 #define EM3027_REG_WATCH_MON 0x0d 32 #define EM3027_REG_WATCH_YEAR 0x0e 33 34 #define EM3027_REG_ALARM_SEC 0x10 35 #define EM3027_REG_ALARM_MIN 0x11 36 #define EM3027_REG_ALARM_HOUR 0x12 37 #define EM3027_REG_ALARM_DATE 0x13 38 #define EM3027_REG_ALARM_DAY 0x14 39 #define EM3027_REG_ALARM_MON 0x15 40 #define EM3027_REG_ALARM_YEAR 0x16 41 42 static struct i2c_driver em3027_driver; 43 44 static int em3027_get_time(struct device *dev, struct rtc_time *tm) 45 { 46 struct i2c_client *client = to_i2c_client(dev); 47 48 unsigned char addr = EM3027_REG_WATCH_SEC; 49 unsigned char buf[7]; 50 51 struct i2c_msg msgs[] = { 52 {/* setup read addr */ 53 .addr = client->addr, 54 .len = 1, 55 .buf = &addr 56 }, 57 {/* read time/date */ 58 .addr = client->addr, 59 .flags = I2C_M_RD, 60 .len = 7, 61 .buf = buf 62 }, 63 }; 64 65 /* read time/date registers */ 66 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 67 dev_err(&client->dev, "%s: read error\n", __func__); 68 return -EIO; 69 } 70 71 tm->tm_sec = bcd2bin(buf[0]); 72 tm->tm_min = bcd2bin(buf[1]); 73 tm->tm_hour = bcd2bin(buf[2]); 74 tm->tm_mday = bcd2bin(buf[3]); 75 tm->tm_wday = bcd2bin(buf[4]); 76 tm->tm_mon = bcd2bin(buf[5]); 77 tm->tm_year = bcd2bin(buf[6]) + 100; 78 79 return 0; 80 } 81 82 static int em3027_set_time(struct device *dev, struct rtc_time *tm) 83 { 84 struct i2c_client *client = to_i2c_client(dev); 85 unsigned char buf[8]; 86 87 struct i2c_msg msg = { 88 .addr = client->addr, 89 .len = 8, 90 .buf = buf, /* write time/date */ 91 }; 92 93 buf[0] = EM3027_REG_WATCH_SEC; 94 buf[1] = bin2bcd(tm->tm_sec); 95 buf[2] = bin2bcd(tm->tm_min); 96 buf[3] = bin2bcd(tm->tm_hour); 97 buf[4] = bin2bcd(tm->tm_mday); 98 buf[5] = bin2bcd(tm->tm_wday); 99 buf[6] = bin2bcd(tm->tm_mon); 100 buf[7] = bin2bcd(tm->tm_year % 100); 101 102 /* write time/date registers */ 103 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) { 104 dev_err(&client->dev, "%s: write error\n", __func__); 105 return -EIO; 106 } 107 108 return 0; 109 } 110 111 static const struct rtc_class_ops em3027_rtc_ops = { 112 .read_time = em3027_get_time, 113 .set_time = em3027_set_time, 114 }; 115 116 static int em3027_probe(struct i2c_client *client, 117 const struct i2c_device_id *id) 118 { 119 struct rtc_device *rtc; 120 121 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 122 return -ENODEV; 123 124 rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name, 125 &em3027_rtc_ops, THIS_MODULE); 126 if (IS_ERR(rtc)) 127 return PTR_ERR(rtc); 128 129 i2c_set_clientdata(client, rtc); 130 131 return 0; 132 } 133 134 static struct i2c_device_id em3027_id[] = { 135 { "em3027", 0 }, 136 { } 137 }; 138 139 static struct i2c_driver em3027_driver = { 140 .driver = { 141 .name = "rtc-em3027", 142 }, 143 .probe = &em3027_probe, 144 .id_table = em3027_id, 145 }; 146 147 module_i2c_driver(em3027_driver); 148 149 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>"); 150 MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver"); 151 MODULE_LICENSE("GPL"); 152