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 18 /* Registers */ 19 #define EM3027_REG_ON_OFF_CTRL 0x00 20 #define EM3027_REG_IRQ_CTRL 0x01 21 #define EM3027_REG_IRQ_FLAGS 0x02 22 #define EM3027_REG_STATUS 0x03 23 #define EM3027_REG_RST_CTRL 0x04 24 25 #define EM3027_REG_WATCH_SEC 0x08 26 #define EM3027_REG_WATCH_MIN 0x09 27 #define EM3027_REG_WATCH_HOUR 0x0a 28 #define EM3027_REG_WATCH_DATE 0x0b 29 #define EM3027_REG_WATCH_DAY 0x0c 30 #define EM3027_REG_WATCH_MON 0x0d 31 #define EM3027_REG_WATCH_YEAR 0x0e 32 33 #define EM3027_REG_ALARM_SEC 0x10 34 #define EM3027_REG_ALARM_MIN 0x11 35 #define EM3027_REG_ALARM_HOUR 0x12 36 #define EM3027_REG_ALARM_DATE 0x13 37 #define EM3027_REG_ALARM_DAY 0x14 38 #define EM3027_REG_ALARM_MON 0x15 39 #define EM3027_REG_ALARM_YEAR 0x16 40 41 static struct i2c_driver em3027_driver; 42 43 static int em3027_get_time(struct device *dev, struct rtc_time *tm) 44 { 45 struct i2c_client *client = to_i2c_client(dev); 46 47 unsigned char addr = EM3027_REG_WATCH_SEC; 48 unsigned char buf[7]; 49 50 struct i2c_msg msgs[] = { 51 {client->addr, 0, 1, &addr}, /* setup read addr */ 52 {client->addr, I2C_M_RD, 7, buf}, /* read time/date */ 53 }; 54 55 /* read time/date registers */ 56 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 57 dev_err(&client->dev, "%s: read error\n", __func__); 58 return -EIO; 59 } 60 61 tm->tm_sec = bcd2bin(buf[0]); 62 tm->tm_min = bcd2bin(buf[1]); 63 tm->tm_hour = bcd2bin(buf[2]); 64 tm->tm_mday = bcd2bin(buf[3]); 65 tm->tm_wday = bcd2bin(buf[4]); 66 tm->tm_mon = bcd2bin(buf[5]); 67 tm->tm_year = bcd2bin(buf[6]) + 100; 68 69 return 0; 70 } 71 72 static int em3027_set_time(struct device *dev, struct rtc_time *tm) 73 { 74 struct i2c_client *client = to_i2c_client(dev); 75 unsigned char buf[8]; 76 77 struct i2c_msg msg = { 78 client->addr, 0, 8, buf, /* write time/date */ 79 }; 80 81 buf[0] = EM3027_REG_WATCH_SEC; 82 buf[1] = bin2bcd(tm->tm_sec); 83 buf[2] = bin2bcd(tm->tm_min); 84 buf[3] = bin2bcd(tm->tm_hour); 85 buf[4] = bin2bcd(tm->tm_mday); 86 buf[5] = bin2bcd(tm->tm_wday); 87 buf[6] = bin2bcd(tm->tm_mon); 88 buf[7] = bin2bcd(tm->tm_year % 100); 89 90 /* write time/date registers */ 91 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) { 92 dev_err(&client->dev, "%s: write error\n", __func__); 93 return -EIO; 94 } 95 96 return 0; 97 } 98 99 static const struct rtc_class_ops em3027_rtc_ops = { 100 .read_time = em3027_get_time, 101 .set_time = em3027_set_time, 102 }; 103 104 static int em3027_probe(struct i2c_client *client, 105 const struct i2c_device_id *id) 106 { 107 struct rtc_device *rtc; 108 109 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 110 return -ENODEV; 111 112 rtc = rtc_device_register(em3027_driver.driver.name, &client->dev, 113 &em3027_rtc_ops, THIS_MODULE); 114 if (IS_ERR(rtc)) 115 return PTR_ERR(rtc); 116 117 i2c_set_clientdata(client, rtc); 118 119 return 0; 120 } 121 122 static int em3027_remove(struct i2c_client *client) 123 { 124 struct rtc_device *rtc = i2c_get_clientdata(client); 125 126 if (rtc) 127 rtc_device_unregister(rtc); 128 129 return 0; 130 } 131 132 static struct i2c_device_id em3027_id[] = { 133 { "em3027", 0 }, 134 { } 135 }; 136 137 static struct i2c_driver em3027_driver = { 138 .driver = { 139 .name = "rtc-em3027", 140 }, 141 .probe = &em3027_probe, 142 .remove = &em3027_remove, 143 .id_table = em3027_id, 144 }; 145 146 static int __init em3027_init(void) 147 { 148 return i2c_add_driver(&em3027_driver); 149 } 150 151 static void __exit em3027_exit(void) 152 { 153 i2c_del_driver(&em3027_driver); 154 } 155 156 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>"); 157 MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver"); 158 MODULE_LICENSE("GPL"); 159 160 module_init(em3027_init); 161 module_exit(em3027_exit); 162