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| 3 | * An rtc/i2c driver for the EM Microelectronic EM3027
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| 4 | * Copyright 2011 CompuLab, Ltd.
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| 5 | *
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| 6 | * Author: Mike Rapoport <[email protected]>
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| 7 | *
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| 8 | * Based on rtc-ds1672.c by Alessandro Zummo <[email protected]>
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| 9 |
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| 10 |
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| 11 | #include <linux/i2c.h>
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| 12 | #include <linux/rtc.h>
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| 13 | #include <linux/bcd.h>
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| 14 | #include <linux/module.h>
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| 15 | #include <linux/of.h>
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| 16 |
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| 17 |
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| 18 | #define EM3027_REG_ON_OFF_CTRL 0x00
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| 19 | #define EM3027_REG_IRQ_CTRL 0x01
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| 20 | #define EM3027_REG_IRQ_FLAGS 0x02
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| 21 | #define EM3027_REG_STATUS 0x03
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| 22 | #define EM3027_REG_RST_CTRL 0x04
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| 23 |
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| 24 | #define EM3027_REG_WATCH_SEC 0x08
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| 25 | #define EM3027_REG_WATCH_MIN 0x09
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| 26 | #define EM3027_REG_WATCH_HOUR 0x0a
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| 27 | #define EM3027_REG_WATCH_DATE 0x0b
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| 28 | #define EM3027_REG_WATCH_DAY 0x0c
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| 29 | #define EM3027_REG_WATCH_MON 0x0d
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| 30 | #define EM3027_REG_WATCH_YEAR 0x0e
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| 31 |
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| 32 | #define EM3027_REG_ALARM_SEC 0x10
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| 33 | #define EM3027_REG_ALARM_MIN 0x11
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| 34 | #define EM3027_REG_ALARM_HOUR 0x12
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| 35 | #define EM3027_REG_ALARM_DATE 0x13
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| 36 | #define EM3027_REG_ALARM_DAY 0x14
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| 37 | #define EM3027_REG_ALARM_MON 0x15
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| 38 | #define EM3027_REG_ALARM_YEAR 0x16
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| 39 |
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| 40 | static struct i2c_driver em3027_driver;
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| 41 |
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| 42 | static int em3027_get_time(struct device *dev, struct rtc_time *tm)
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| 43 | {
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| 44 | struct i2c_client *client = to_i2c_client(dev);
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| 45 |
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| 46 | unsigned char addr = EM3027_REG_WATCH_SEC;
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| 47 | unsigned char buf[7];
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| 48 |
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| 49 | struct i2c_msg msgs[] = {
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| 50 | {
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| 51 | .addr = client->addr,
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| 52 | .len = 1,
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| 53 | .buf = &addr
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| 54 | },
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| 55 | {
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| 56 | .addr = client->addr,
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| 57 | .flags = I2C_M_RD,
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| 58 | .len = 7,
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| 59 | .buf = buf
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| 60 | },
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| 61 | };
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| 62 |
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| 63 |
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| 64 | if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
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| 65 | dev_err(&client->dev, "%s: read error\n", __func__);
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| 66 | return -EIO;
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| 67 | }
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| 68 |
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| 69 | tm->tm_sec = bcd2bin(buf[0]);
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| 70 | tm->tm_min = bcd2bin(buf[1]);
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| 71 | tm->tm_hour = bcd2bin(buf[2]);
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| 72 | tm->tm_mday = bcd2bin(buf[3]);
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| 73 | tm->tm_wday = bcd2bin(buf[4]);
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| 74 | tm->tm_mon = bcd2bin(buf[5]) - 1;
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| 75 | tm->tm_year = bcd2bin(buf[6]) + 100;
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| 76 |
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| 77 | return 0;
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| 78 | }
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| 79 |
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| 80 | static int em3027_set_time(struct device *dev, struct rtc_time *tm)
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| 81 | {
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| 82 | struct i2c_client *client = to_i2c_client(dev);
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| 83 | unsigned char buf[8];
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| 84 |
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| 85 | struct i2c_msg msg = {
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| 86 | .addr = client->addr,
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| 87 | .len = 8,
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| 88 | .buf = buf,
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| 89 | };
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| 90 |
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| 91 | buf[0] = EM3027_REG_WATCH_SEC;
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| 92 | buf[1] = bin2bcd(tm->tm_sec);
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| 93 | buf[2] = bin2bcd(tm->tm_min);
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| 94 | buf[3] = bin2bcd(tm->tm_hour);
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| 95 | buf[4] = bin2bcd(tm->tm_mday);
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| 96 | buf[5] = bin2bcd(tm->tm_wday);
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| 97 | buf[6] = bin2bcd(tm->tm_mon + 1);
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| 98 | buf[7] = bin2bcd(tm->tm_year % 100);
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| 99 |
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| 100 |
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| 101 | if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
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| 102 | dev_err(&client->dev, "%s: write error\n", __func__);
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| 103 | return -EIO;
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| 104 | }
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| 105 |
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| 106 | return 0;
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| 107 | }
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| 108 |
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| 109 | static const struct rtc_class_ops em3027_rtc_ops = {
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| 110 | .read_time = em3027_get_time,
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| 111 | .set_time = em3027_set_time,
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| 112 | };
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| 113 |
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| 114 | static int em3027_probe(struct i2c_client *client)
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| 115 | {
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| 116 | struct rtc_device *rtc;
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| 117 |
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| 118 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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| 119 | return -ENODEV;
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| 120 |
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| 121 | rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
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| 122 | &em3027_rtc_ops, THIS_MODULE);
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| 123 | if (IS_ERR(rtc))
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| 124 | return PTR_ERR(rtc);
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| 125 |
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| 126 | i2c_set_clientdata(client, rtc);
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| 127 |
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| 128 | return 0;
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| 129 | }
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| 130 |
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| 131 | static const struct i2c_device_id em3027_id[] = {
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| 132 | { .name = "em3027" },
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| 133 | { }
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| 134 | };
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| 135 | MODULE_DEVICE_TABLE(i2c, em3027_id);
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| 136 |
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| 137 | #ifdef CONFIG_OF
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| 138 | static const struct of_device_id em3027_of_match[] = {
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| 139 | { .compatible = "emmicro,em3027", },
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| 140 | {}
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| 141 | };
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| 142 | MODULE_DEVICE_TABLE(of, em3027_of_match);
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| 143 | #endif
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| 144 |
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| 145 | static struct i2c_driver em3027_driver = {
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| 146 | .driver = {
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| 147 | .name = "rtc-em3027",
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| 148 | .of_match_table = of_match_ptr(em3027_of_match),
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| 149 | },
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| 150 | .probe = em3027_probe,
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| 151 | .id_table = em3027_id,
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| 152 | };
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| 153 |
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| 154 | module_i2c_driver(em3027_driver);
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| 155 |
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| 156 | MODULE_AUTHOR("Mike Rapoport <[email protected]>");
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| 157 | MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
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| 158 | MODULE_LICENSE("GPL");
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