1 /* 2 * An I2C driver for the PCF85063 RTC 3 * Copyright 2014 Rose Technology 4 * 5 * Author: Søren Andersen <san@rosetechnology.dk> 6 * Maintainers: http://www.nslu2-linux.org/ 7 * 8 * based on the other drivers in this same directory. 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 #include <linux/i2c.h> 15 #include <linux/bcd.h> 16 #include <linux/rtc.h> 17 #include <linux/module.h> 18 19 #define DRV_VERSION "0.0.1" 20 21 #define PCF85063_REG_CTRL1 0x00 /* status */ 22 #define PCF85063_REG_CTRL2 0x01 23 24 #define PCF85063_REG_SC 0x04 /* datetime */ 25 #define PCF85063_REG_MN 0x05 26 #define PCF85063_REG_HR 0x06 27 #define PCF85063_REG_DM 0x07 28 #define PCF85063_REG_DW 0x08 29 #define PCF85063_REG_MO 0x09 30 #define PCF85063_REG_YR 0x0A 31 32 #define PCF85063_MO_C 0x80 /* century */ 33 34 static struct i2c_driver pcf85063_driver; 35 36 struct pcf85063 { 37 struct rtc_device *rtc; 38 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 39 int voltage_low; /* indicates if a low_voltage was detected */ 40 }; 41 42 /* 43 * In the routines that deal directly with the pcf85063 hardware, we use 44 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 45 */ 46 static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm) 47 { 48 struct pcf85063 *pcf85063 = i2c_get_clientdata(client); 49 unsigned char buf[13] = { PCF85063_REG_CTRL1 }; 50 struct i2c_msg msgs[] = { 51 {/* setup read ptr */ 52 .addr = client->addr, 53 .len = 1, 54 .buf = buf 55 }, 56 {/* read status + date */ 57 .addr = client->addr, 58 .flags = I2C_M_RD, 59 .len = 13, 60 .buf = buf 61 }, 62 }; 63 64 /* read registers */ 65 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 66 dev_err(&client->dev, "%s: read error\n", __func__); 67 return -EIO; 68 } 69 70 tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F); 71 tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F); 72 tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */ 73 tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F); 74 tm->tm_wday = buf[PCF85063_REG_DW] & 0x07; 75 tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 76 tm->tm_year = bcd2bin(buf[PCF85063_REG_YR]); 77 if (tm->tm_year < 70) 78 tm->tm_year += 100; /* assume we are in 1970...2069 */ 79 /* detect the polarity heuristically. see note above. */ 80 pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ? 81 (tm->tm_year >= 100) : (tm->tm_year < 100); 82 83 /* the clock can give out invalid datetime, but we cannot return 84 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 85 */ 86 if (rtc_valid_tm(tm) < 0) 87 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 88 89 return 0; 90 } 91 92 static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm) 93 { 94 int i = 0, err = 0; 95 unsigned char buf[11]; 96 97 /* Control & status */ 98 buf[PCF85063_REG_CTRL1] = 0; 99 buf[PCF85063_REG_CTRL2] = 5; 100 101 /* hours, minutes and seconds */ 102 buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F; 103 104 buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min); 105 buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour); 106 107 /* Day of month, 1 - 31 */ 108 buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday); 109 110 /* Day, 0 - 6 */ 111 buf[PCF85063_REG_DW] = tm->tm_wday & 0x07; 112 113 /* month, 1 - 12 */ 114 buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1); 115 116 /* year and century */ 117 buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100); 118 119 /* write register's data */ 120 for (i = 0; i < sizeof(buf); i++) { 121 unsigned char data[2] = { i, buf[i] }; 122 123 err = i2c_master_send(client, data, sizeof(data)); 124 if (err != sizeof(data)) { 125 dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n", 126 __func__, err, data[0], data[1]); 127 return -EIO; 128 } 129 } 130 131 return 0; 132 } 133 134 static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm) 135 { 136 return pcf85063_get_datetime(to_i2c_client(dev), tm); 137 } 138 139 static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm) 140 { 141 return pcf85063_set_datetime(to_i2c_client(dev), tm); 142 } 143 144 static const struct rtc_class_ops pcf85063_rtc_ops = { 145 .read_time = pcf85063_rtc_read_time, 146 .set_time = pcf85063_rtc_set_time 147 }; 148 149 static int pcf85063_probe(struct i2c_client *client, 150 const struct i2c_device_id *id) 151 { 152 struct pcf85063 *pcf85063; 153 154 dev_dbg(&client->dev, "%s\n", __func__); 155 156 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 157 return -ENODEV; 158 159 pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063), 160 GFP_KERNEL); 161 if (!pcf85063) 162 return -ENOMEM; 163 164 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 165 166 i2c_set_clientdata(client, pcf85063); 167 168 pcf85063->rtc = devm_rtc_device_register(&client->dev, 169 pcf85063_driver.driver.name, 170 &pcf85063_rtc_ops, THIS_MODULE); 171 172 return PTR_ERR_OR_ZERO(pcf85063->rtc); 173 } 174 175 static const struct i2c_device_id pcf85063_id[] = { 176 { "pcf85063", 0 }, 177 { } 178 }; 179 MODULE_DEVICE_TABLE(i2c, pcf85063_id); 180 181 #ifdef CONFIG_OF 182 static const struct of_device_id pcf85063_of_match[] = { 183 { .compatible = "nxp,pcf85063" }, 184 {} 185 }; 186 MODULE_DEVICE_TABLE(of, pcf85063_of_match); 187 #endif 188 189 static struct i2c_driver pcf85063_driver = { 190 .driver = { 191 .name = "rtc-pcf85063", 192 .owner = THIS_MODULE, 193 .of_match_table = of_match_ptr(pcf85063_of_match), 194 }, 195 .probe = pcf85063_probe, 196 .id_table = pcf85063_id, 197 }; 198 199 module_i2c_driver(pcf85063_driver); 200 201 MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>"); 202 MODULE_DESCRIPTION("PCF85063 RTC driver"); 203 MODULE_LICENSE("GPL"); 204 MODULE_VERSION(DRV_VERSION); 205