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 DRV_VERSION "0.0.1" 24 25 #define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */ 26 #define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */ 27 #define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */ 28 #define PCF2127_REG_SC (0x03) /* datetime */ 29 #define PCF2127_REG_MN (0x04) 30 #define PCF2127_REG_HR (0x05) 31 #define PCF2127_REG_DM (0x06) 32 #define PCF2127_REG_DW (0x07) 33 #define PCF2127_REG_MO (0x08) 34 #define PCF2127_REG_YR (0x09) 35 36 #define PCF2127_OSF BIT(7) /* Oscillator Fail flag */ 37 38 static struct i2c_driver pcf2127_driver; 39 40 struct pcf2127 { 41 struct rtc_device *rtc; 42 int voltage_low; /* indicates if a low_voltage was detected */ 43 int oscillator_failed; /* OSF was detected and date is unreliable */ 44 }; 45 46 /* 47 * In the routines that deal directly with the pcf2127 hardware, we use 48 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 49 */ 50 static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) 51 { 52 struct pcf2127 *pcf2127 = i2c_get_clientdata(client); 53 unsigned char buf[10] = { PCF2127_REG_CTRL1 }; 54 55 /* read registers */ 56 if (i2c_master_send(client, buf, 1) != 1 || 57 i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { 58 dev_err(&client->dev, "%s: read error\n", __func__); 59 return -EIO; 60 } 61 62 if (buf[PCF2127_REG_CTRL3] & 0x04) { 63 pcf2127->voltage_low = 1; 64 dev_info(&client->dev, 65 "low voltage detected, check/replace RTC battery.\n"); 66 } 67 68 if (buf[PCF2127_REG_SC] & PCF2127_OSF) { 69 /* 70 * no need clear the flag here, 71 * it will be cleared once the new date is saved 72 */ 73 pcf2127->oscillator_failed = 1; 74 dev_warn(&client->dev, 75 "oscillator stop detected, date/time is not reliable\n"); 76 return -EINVAL; 77 } 78 79 dev_dbg(&client->dev, 80 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " 81 "sec=%02x, min=%02x, hr=%02x, " 82 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 83 __func__, 84 buf[0], buf[1], buf[2], 85 buf[3], buf[4], buf[5], 86 buf[6], buf[7], buf[8], buf[9]); 87 88 89 tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); 90 tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); 91 tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ 92 tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); 93 tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; 94 tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 95 tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); 96 if (tm->tm_year < 70) 97 tm->tm_year += 100; /* assume we are in 1970...2069 */ 98 99 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 100 "mday=%d, mon=%d, year=%d, wday=%d\n", 101 __func__, 102 tm->tm_sec, tm->tm_min, tm->tm_hour, 103 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 104 105 return rtc_valid_tm(tm); 106 } 107 108 static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) 109 { 110 struct pcf2127 *pcf2127 = i2c_get_clientdata(client); 111 unsigned char buf[8]; 112 int i = 0, err; 113 114 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 115 "mday=%d, mon=%d, year=%d, wday=%d\n", 116 __func__, 117 tm->tm_sec, tm->tm_min, tm->tm_hour, 118 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 119 120 /* start register address */ 121 buf[i++] = PCF2127_REG_SC; 122 123 /* hours, minutes and seconds */ 124 buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */ 125 buf[i++] = bin2bcd(tm->tm_min); 126 buf[i++] = bin2bcd(tm->tm_hour); 127 buf[i++] = bin2bcd(tm->tm_mday); 128 buf[i++] = tm->tm_wday & 0x07; 129 130 /* month, 1 - 12 */ 131 buf[i++] = bin2bcd(tm->tm_mon + 1); 132 133 /* year */ 134 buf[i++] = bin2bcd(tm->tm_year % 100); 135 136 /* write register's data */ 137 err = i2c_master_send(client, buf, i); 138 if (err != i) { 139 dev_err(&client->dev, 140 "%s: err=%d", __func__, err); 141 return -EIO; 142 } 143 144 /* clear OSF flag in client data */ 145 pcf2127->oscillator_failed = 0; 146 147 return 0; 148 } 149 150 #ifdef CONFIG_RTC_INTF_DEV 151 static int pcf2127_rtc_ioctl(struct device *dev, 152 unsigned int cmd, unsigned long arg) 153 { 154 struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev)); 155 156 switch (cmd) { 157 case RTC_VL_READ: 158 if (pcf2127->voltage_low) 159 dev_info(dev, "low voltage detected, check/replace battery\n"); 160 if (pcf2127->oscillator_failed) 161 dev_info(dev, "oscillator stop detected, date/time is not reliable\n"); 162 163 if (copy_to_user((void __user *)arg, &pcf2127->voltage_low, 164 sizeof(int))) 165 return -EFAULT; 166 return 0; 167 default: 168 return -ENOIOCTLCMD; 169 } 170 } 171 #else 172 #define pcf2127_rtc_ioctl NULL 173 #endif 174 175 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) 176 { 177 return pcf2127_get_datetime(to_i2c_client(dev), tm); 178 } 179 180 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) 181 { 182 return pcf2127_set_datetime(to_i2c_client(dev), tm); 183 } 184 185 static const struct rtc_class_ops pcf2127_rtc_ops = { 186 .ioctl = pcf2127_rtc_ioctl, 187 .read_time = pcf2127_rtc_read_time, 188 .set_time = pcf2127_rtc_set_time, 189 }; 190 191 static int pcf2127_probe(struct i2c_client *client, 192 const struct i2c_device_id *id) 193 { 194 struct pcf2127 *pcf2127; 195 196 dev_dbg(&client->dev, "%s\n", __func__); 197 198 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 199 return -ENODEV; 200 201 pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), 202 GFP_KERNEL); 203 if (!pcf2127) 204 return -ENOMEM; 205 206 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 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"); 245 MODULE_VERSION(DRV_VERSION); 246