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 #include <linux/of.h> 19 20 /* Registers */ 21 #define EM3027_REG_ON_OFF_CTRL 0x00 22 #define EM3027_REG_IRQ_CTRL 0x01 23 #define EM3027_REG_IRQ_FLAGS 0x02 24 #define EM3027_REG_STATUS 0x03 25 #define EM3027_REG_RST_CTRL 0x04 26 27 #define EM3027_REG_WATCH_SEC 0x08 28 #define EM3027_REG_WATCH_MIN 0x09 29 #define EM3027_REG_WATCH_HOUR 0x0a 30 #define EM3027_REG_WATCH_DATE 0x0b 31 #define EM3027_REG_WATCH_DAY 0x0c 32 #define EM3027_REG_WATCH_MON 0x0d 33 #define EM3027_REG_WATCH_YEAR 0x0e 34 35 #define EM3027_REG_ALARM_SEC 0x10 36 #define EM3027_REG_ALARM_MIN 0x11 37 #define EM3027_REG_ALARM_HOUR 0x12 38 #define EM3027_REG_ALARM_DATE 0x13 39 #define EM3027_REG_ALARM_DAY 0x14 40 #define EM3027_REG_ALARM_MON 0x15 41 #define EM3027_REG_ALARM_YEAR 0x16 42 43 static struct i2c_driver em3027_driver; 44 45 static int em3027_get_time(struct device *dev, struct rtc_time *tm) 46 { 47 struct i2c_client *client = to_i2c_client(dev); 48 49 unsigned char addr = EM3027_REG_WATCH_SEC; 50 unsigned char buf[7]; 51 52 struct i2c_msg msgs[] = { 53 {/* setup read addr */ 54 .addr = client->addr, 55 .len = 1, 56 .buf = &addr 57 }, 58 {/* read time/date */ 59 .addr = client->addr, 60 .flags = I2C_M_RD, 61 .len = 7, 62 .buf = buf 63 }, 64 }; 65 66 /* read time/date registers */ 67 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 68 dev_err(&client->dev, "%s: read error\n", __func__); 69 return -EIO; 70 } 71 72 tm->tm_sec = bcd2bin(buf[0]); 73 tm->tm_min = bcd2bin(buf[1]); 74 tm->tm_hour = bcd2bin(buf[2]); 75 tm->tm_mday = bcd2bin(buf[3]); 76 tm->tm_wday = bcd2bin(buf[4]); 77 tm->tm_mon = bcd2bin(buf[5]); 78 tm->tm_year = bcd2bin(buf[6]) + 100; 79 80 return 0; 81 } 82 83 static int em3027_set_time(struct device *dev, struct rtc_time *tm) 84 { 85 struct i2c_client *client = to_i2c_client(dev); 86 unsigned char buf[8]; 87 88 struct i2c_msg msg = { 89 .addr = client->addr, 90 .len = 8, 91 .buf = buf, /* write time/date */ 92 }; 93 94 buf[0] = EM3027_REG_WATCH_SEC; 95 buf[1] = bin2bcd(tm->tm_sec); 96 buf[2] = bin2bcd(tm->tm_min); 97 buf[3] = bin2bcd(tm->tm_hour); 98 buf[4] = bin2bcd(tm->tm_mday); 99 buf[5] = bin2bcd(tm->tm_wday); 100 buf[6] = bin2bcd(tm->tm_mon); 101 buf[7] = bin2bcd(tm->tm_year % 100); 102 103 /* write time/date registers */ 104 if ((i2c_transfer(client->adapter, &msg, 1)) != 1) { 105 dev_err(&client->dev, "%s: write error\n", __func__); 106 return -EIO; 107 } 108 109 return 0; 110 } 111 112 static const struct rtc_class_ops em3027_rtc_ops = { 113 .read_time = em3027_get_time, 114 .set_time = em3027_set_time, 115 }; 116 117 static int em3027_probe(struct i2c_client *client, 118 const struct i2c_device_id *id) 119 { 120 struct rtc_device *rtc; 121 122 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 123 return -ENODEV; 124 125 rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name, 126 &em3027_rtc_ops, THIS_MODULE); 127 if (IS_ERR(rtc)) 128 return PTR_ERR(rtc); 129 130 i2c_set_clientdata(client, rtc); 131 132 return 0; 133 } 134 135 static const struct i2c_device_id em3027_id[] = { 136 { "em3027", 0 }, 137 { } 138 }; 139 MODULE_DEVICE_TABLE(i2c, em3027_id); 140 141 #ifdef CONFIG_OF 142 static const struct of_device_id em3027_of_match[] = { 143 { .compatible = "emmicro,em3027", }, 144 {} 145 }; 146 MODULE_DEVICE_TABLE(of, em3027_of_match); 147 #endif 148 149 static struct i2c_driver em3027_driver = { 150 .driver = { 151 .name = "rtc-em3027", 152 .of_match_table = of_match_ptr(em3027_of_match), 153 }, 154 .probe = &em3027_probe, 155 .id_table = em3027_id, 156 }; 157 158 module_i2c_driver(em3027_driver); 159 160 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>"); 161 MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver"); 162 MODULE_LICENSE("GPL"); 163