1 /* 2 * An I2C driver for the NXP PCF2127 RTC 3 * Copyright 2013 Til-Technologies 4 * 5 * Author: Renaud Cerrato <r.cerrato@til-technologies.fr> 6 * 7 * based on the other drivers in this same directory. 8 * 9 * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 16 #include <linux/i2c.h> 17 #include <linux/bcd.h> 18 #include <linux/rtc.h> 19 #include <linux/slab.h> 20 #include <linux/module.h> 21 #include <linux/of.h> 22 23 #define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */ 24 #define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */ 25 26 #define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */ 27 #define PCF2127_REG_CTRL3_BLF BIT(2) 28 29 #define PCF2127_REG_SC (0x03) /* datetime */ 30 #define PCF2127_REG_MN (0x04) 31 #define PCF2127_REG_HR (0x05) 32 #define PCF2127_REG_DM (0x06) 33 #define PCF2127_REG_DW (0x07) 34 #define PCF2127_REG_MO (0x08) 35 #define PCF2127_REG_YR (0x09) 36 37 #define PCF2127_OSF BIT(7) /* Oscillator Fail flag */ 38 39 static struct i2c_driver pcf2127_driver; 40 41 struct pcf2127 { 42 struct rtc_device *rtc; 43 }; 44 45 /* 46 * In the routines that deal directly with the pcf2127 hardware, we use 47 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 48 */ 49 static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) 50 { 51 unsigned char buf[10] = { PCF2127_REG_CTRL1 }; 52 53 /* read registers */ 54 if (i2c_master_send(client, buf, 1) != 1 || 55 i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { 56 dev_err(&client->dev, "%s: read error\n", __func__); 57 return -EIO; 58 } 59 60 if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF) 61 dev_info(&client->dev, 62 "low voltage detected, check/replace RTC battery.\n"); 63 64 if (buf[PCF2127_REG_SC] & PCF2127_OSF) { 65 /* 66 * no need clear the flag here, 67 * it will be cleared once the new date is saved 68 */ 69 dev_warn(&client->dev, 70 "oscillator stop detected, date/time is not reliable\n"); 71 return -EINVAL; 72 } 73 74 dev_dbg(&client->dev, 75 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " 76 "sec=%02x, min=%02x, hr=%02x, " 77 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 78 __func__, 79 buf[0], buf[1], buf[2], 80 buf[3], buf[4], buf[5], 81 buf[6], buf[7], buf[8], buf[9]); 82 83 84 tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); 85 tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); 86 tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ 87 tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); 88 tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; 89 tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 90 tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); 91 if (tm->tm_year < 70) 92 tm->tm_year += 100; /* assume we are in 1970...2069 */ 93 94 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 95 "mday=%d, mon=%d, year=%d, wday=%d\n", 96 __func__, 97 tm->tm_sec, tm->tm_min, tm->tm_hour, 98 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 99 100 return rtc_valid_tm(tm); 101 } 102 103 static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) 104 { 105 unsigned char buf[8]; 106 int i = 0, err; 107 108 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 109 "mday=%d, mon=%d, year=%d, wday=%d\n", 110 __func__, 111 tm->tm_sec, tm->tm_min, tm->tm_hour, 112 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 113 114 /* start register address */ 115 buf[i++] = PCF2127_REG_SC; 116 117 /* hours, minutes and seconds */ 118 buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */ 119 buf[i++] = bin2bcd(tm->tm_min); 120 buf[i++] = bin2bcd(tm->tm_hour); 121 buf[i++] = bin2bcd(tm->tm_mday); 122 buf[i++] = tm->tm_wday & 0x07; 123 124 /* month, 1 - 12 */ 125 buf[i++] = bin2bcd(tm->tm_mon + 1); 126 127 /* year */ 128 buf[i++] = bin2bcd(tm->tm_year % 100); 129 130 /* write register's data */ 131 err = i2c_master_send(client, buf, i); 132 if (err != i) { 133 dev_err(&client->dev, 134 "%s: err=%d", __func__, err); 135 return -EIO; 136 } 137 138 return 0; 139 } 140 141 #ifdef CONFIG_RTC_INTF_DEV 142 static int pcf2127_rtc_ioctl(struct device *dev, 143 unsigned int cmd, unsigned long arg) 144 { 145 struct i2c_client *client = to_i2c_client(dev); 146 unsigned char buf = PCF2127_REG_CTRL3; 147 int touser; 148 int ret; 149 150 switch (cmd) { 151 case RTC_VL_READ: 152 ret = i2c_master_send(client, &buf, 1); 153 if (!ret) 154 ret = -EIO; 155 if (ret < 0) 156 return ret; 157 158 ret = i2c_master_recv(client, &buf, 1); 159 if (!ret) 160 ret = -EIO; 161 if (ret < 0) 162 return ret; 163 164 touser = buf & PCF2127_REG_CTRL3_BLF ? 1 : 0; 165 166 if (copy_to_user((void __user *)arg, &touser, sizeof(int))) 167 return -EFAULT; 168 return 0; 169 default: 170 return -ENOIOCTLCMD; 171 } 172 } 173 #else 174 #define pcf2127_rtc_ioctl NULL 175 #endif 176 177 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) 178 { 179 return pcf2127_get_datetime(to_i2c_client(dev), tm); 180 } 181 182 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) 183 { 184 return pcf2127_set_datetime(to_i2c_client(dev), tm); 185 } 186 187 static const struct rtc_class_ops pcf2127_rtc_ops = { 188 .ioctl = pcf2127_rtc_ioctl, 189 .read_time = pcf2127_rtc_read_time, 190 .set_time = pcf2127_rtc_set_time, 191 }; 192 193 static int pcf2127_probe(struct i2c_client *client, 194 const struct i2c_device_id *id) 195 { 196 struct pcf2127 *pcf2127; 197 198 dev_dbg(&client->dev, "%s\n", __func__); 199 200 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 201 return -ENODEV; 202 203 pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), 204 GFP_KERNEL); 205 if (!pcf2127) 206 return -ENOMEM; 207 208 i2c_set_clientdata(client, pcf2127); 209 210 pcf2127->rtc = devm_rtc_device_register(&client->dev, 211 pcf2127_driver.driver.name, 212 &pcf2127_rtc_ops, THIS_MODULE); 213 214 return PTR_ERR_OR_ZERO(pcf2127->rtc); 215 } 216 217 static const struct i2c_device_id pcf2127_id[] = { 218 { "pcf2127", 0 }, 219 { } 220 }; 221 MODULE_DEVICE_TABLE(i2c, pcf2127_id); 222 223 #ifdef CONFIG_OF 224 static const struct of_device_id pcf2127_of_match[] = { 225 { .compatible = "nxp,pcf2127" }, 226 {} 227 }; 228 MODULE_DEVICE_TABLE(of, pcf2127_of_match); 229 #endif 230 231 static struct i2c_driver pcf2127_driver = { 232 .driver = { 233 .name = "rtc-pcf2127", 234 .of_match_table = of_match_ptr(pcf2127_of_match), 235 }, 236 .probe = pcf2127_probe, 237 .id_table = pcf2127_id, 238 }; 239 240 module_i2c_driver(pcf2127_driver); 241 242 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>"); 243 MODULE_DESCRIPTION("NXP PCF2127 RTC driver"); 244 MODULE_LICENSE("GPL v2"); 245