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 static struct i2c_driver pcf2127_driver; 37 38 struct pcf2127 { 39 struct rtc_device *rtc; 40 int voltage_low; /* indicates if a low_voltage was detected */ 41 }; 42 43 /* 44 * In the routines that deal directly with the pcf2127 hardware, we use 45 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 46 */ 47 static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) 48 { 49 struct pcf2127 *pcf2127 = i2c_get_clientdata(client); 50 unsigned char buf[10] = { PCF2127_REG_CTRL1 }; 51 52 /* read registers */ 53 if (i2c_master_send(client, buf, 1) != 1 || 54 i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { 55 dev_err(&client->dev, "%s: read error\n", __func__); 56 return -EIO; 57 } 58 59 if (buf[PCF2127_REG_CTRL3] & 0x04) { 60 pcf2127->voltage_low = 1; 61 dev_info(&client->dev, 62 "low voltage detected, date/time is not reliable.\n"); 63 } 64 65 dev_dbg(&client->dev, 66 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " 67 "sec=%02x, min=%02x, hr=%02x, " 68 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 69 __func__, 70 buf[0], buf[1], buf[2], 71 buf[3], buf[4], buf[5], 72 buf[6], buf[7], buf[8], buf[9]); 73 74 75 tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); 76 tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); 77 tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ 78 tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); 79 tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; 80 tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 81 tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); 82 if (tm->tm_year < 70) 83 tm->tm_year += 100; /* assume we are in 1970...2069 */ 84 85 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 86 "mday=%d, mon=%d, year=%d, wday=%d\n", 87 __func__, 88 tm->tm_sec, tm->tm_min, tm->tm_hour, 89 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 90 91 /* the clock can give out invalid datetime, but we cannot return 92 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 93 */ 94 if (rtc_valid_tm(tm) < 0) 95 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 96 97 return 0; 98 } 99 100 static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) 101 { 102 unsigned char buf[8]; 103 int i = 0, err; 104 105 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 106 "mday=%d, mon=%d, year=%d, wday=%d\n", 107 __func__, 108 tm->tm_sec, tm->tm_min, tm->tm_hour, 109 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 110 111 /* start register address */ 112 buf[i++] = PCF2127_REG_SC; 113 114 /* hours, minutes and seconds */ 115 buf[i++] = bin2bcd(tm->tm_sec); 116 buf[i++] = bin2bcd(tm->tm_min); 117 buf[i++] = bin2bcd(tm->tm_hour); 118 buf[i++] = bin2bcd(tm->tm_mday); 119 buf[i++] = tm->tm_wday & 0x07; 120 121 /* month, 1 - 12 */ 122 buf[i++] = bin2bcd(tm->tm_mon + 1); 123 124 /* year */ 125 buf[i++] = bin2bcd(tm->tm_year % 100); 126 127 /* write register's data */ 128 err = i2c_master_send(client, buf, i); 129 if (err != i) { 130 dev_err(&client->dev, 131 "%s: err=%d", __func__, err); 132 return -EIO; 133 } 134 135 return 0; 136 } 137 138 #ifdef CONFIG_RTC_INTF_DEV 139 static int pcf2127_rtc_ioctl(struct device *dev, 140 unsigned int cmd, unsigned long arg) 141 { 142 struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev)); 143 144 switch (cmd) { 145 case RTC_VL_READ: 146 if (pcf2127->voltage_low) 147 dev_info(dev, "low voltage detected, date/time is not reliable.\n"); 148 149 if (copy_to_user((void __user *)arg, &pcf2127->voltage_low, 150 sizeof(int))) 151 return -EFAULT; 152 return 0; 153 default: 154 return -ENOIOCTLCMD; 155 } 156 } 157 #else 158 #define pcf2127_rtc_ioctl NULL 159 #endif 160 161 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) 162 { 163 return pcf2127_get_datetime(to_i2c_client(dev), tm); 164 } 165 166 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) 167 { 168 return pcf2127_set_datetime(to_i2c_client(dev), tm); 169 } 170 171 static const struct rtc_class_ops pcf2127_rtc_ops = { 172 .ioctl = pcf2127_rtc_ioctl, 173 .read_time = pcf2127_rtc_read_time, 174 .set_time = pcf2127_rtc_set_time, 175 }; 176 177 static int pcf2127_probe(struct i2c_client *client, 178 const struct i2c_device_id *id) 179 { 180 struct pcf2127 *pcf2127; 181 182 dev_dbg(&client->dev, "%s\n", __func__); 183 184 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 185 return -ENODEV; 186 187 pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), 188 GFP_KERNEL); 189 if (!pcf2127) 190 return -ENOMEM; 191 192 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 193 194 i2c_set_clientdata(client, pcf2127); 195 196 pcf2127->rtc = devm_rtc_device_register(&client->dev, 197 pcf2127_driver.driver.name, 198 &pcf2127_rtc_ops, THIS_MODULE); 199 200 if (IS_ERR(pcf2127->rtc)) 201 return PTR_ERR(pcf2127->rtc); 202 203 return 0; 204 } 205 206 static const struct i2c_device_id pcf2127_id[] = { 207 { "pcf2127", 0 }, 208 { } 209 }; 210 MODULE_DEVICE_TABLE(i2c, pcf2127_id); 211 212 #ifdef CONFIG_OF 213 static const struct of_device_id pcf2127_of_match[] = { 214 { .compatible = "nxp,pcf2127" }, 215 {} 216 }; 217 MODULE_DEVICE_TABLE(of, pcf2127_of_match); 218 #endif 219 220 static struct i2c_driver pcf2127_driver = { 221 .driver = { 222 .name = "rtc-pcf2127", 223 .owner = THIS_MODULE, 224 .of_match_table = of_match_ptr(pcf2127_of_match), 225 }, 226 .probe = pcf2127_probe, 227 .id_table = pcf2127_id, 228 }; 229 230 module_i2c_driver(pcf2127_driver); 231 232 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>"); 233 MODULE_DESCRIPTION("NXP PCF2127 RTC driver"); 234 MODULE_LICENSE("GPL"); 235 MODULE_VERSION(DRV_VERSION); 236