1 /* 2 * An rtc/i2c driver for the Dallas DS1672 3 * Copyright 2005-06 Tower Technologies 4 * 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/i2c.h> 13 #include <linux/rtc.h> 14 15 #define DRV_VERSION "0.4" 16 17 /* Registers */ 18 19 #define DS1672_REG_CNT_BASE 0 20 #define DS1672_REG_CONTROL 4 21 #define DS1672_REG_TRICKLE 5 22 23 #define DS1672_REG_CONTROL_EOSC 0x80 24 25 static struct i2c_driver ds1672_driver; 26 27 /* 28 * In the routines that deal directly with the ds1672 hardware, we use 29 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 30 * Epoch is initialized as 2000. Time is set to UTC. 31 */ 32 static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm) 33 { 34 unsigned long time; 35 unsigned char addr = DS1672_REG_CNT_BASE; 36 unsigned char buf[4]; 37 38 struct i2c_msg msgs[] = { 39 {client->addr, 0, 1, &addr}, /* setup read ptr */ 40 {client->addr, I2C_M_RD, 4, buf}, /* read date */ 41 }; 42 43 /* read date registers */ 44 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 45 dev_err(&client->dev, "%s: read error\n", __func__); 46 return -EIO; 47 } 48 49 dev_dbg(&client->dev, 50 "%s: raw read data - counters=%02x,%02x,%02x,%02x\n", 51 __func__, buf[0], buf[1], buf[2], buf[3]); 52 53 time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; 54 55 rtc_time_to_tm(time, tm); 56 57 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 58 "mday=%d, mon=%d, year=%d, wday=%d\n", 59 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, 60 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 61 62 return 0; 63 } 64 65 static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs) 66 { 67 int xfer; 68 unsigned char buf[6]; 69 70 buf[0] = DS1672_REG_CNT_BASE; 71 buf[1] = secs & 0x000000FF; 72 buf[2] = (secs & 0x0000FF00) >> 8; 73 buf[3] = (secs & 0x00FF0000) >> 16; 74 buf[4] = (secs & 0xFF000000) >> 24; 75 buf[5] = 0; /* set control reg to enable counting */ 76 77 xfer = i2c_master_send(client, buf, 6); 78 if (xfer != 6) { 79 dev_err(&client->dev, "%s: send: %d\n", __func__, xfer); 80 return -EIO; 81 } 82 83 return 0; 84 } 85 86 static int ds1672_set_datetime(struct i2c_client *client, struct rtc_time *tm) 87 { 88 unsigned long secs; 89 90 dev_dbg(&client->dev, 91 "%s: secs=%d, mins=%d, hours=%d, " 92 "mday=%d, mon=%d, year=%d, wday=%d\n", 93 __func__, 94 tm->tm_sec, tm->tm_min, tm->tm_hour, 95 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 96 97 rtc_tm_to_time(tm, &secs); 98 99 return ds1672_set_mmss(client, secs); 100 } 101 102 static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm) 103 { 104 return ds1672_get_datetime(to_i2c_client(dev), tm); 105 } 106 107 static int ds1672_rtc_set_time(struct device *dev, struct rtc_time *tm) 108 { 109 return ds1672_set_datetime(to_i2c_client(dev), tm); 110 } 111 112 static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs) 113 { 114 return ds1672_set_mmss(to_i2c_client(dev), secs); 115 } 116 117 static int ds1672_get_control(struct i2c_client *client, u8 *status) 118 { 119 unsigned char addr = DS1672_REG_CONTROL; 120 121 struct i2c_msg msgs[] = { 122 {client->addr, 0, 1, &addr}, /* setup read ptr */ 123 {client->addr, I2C_M_RD, 1, status}, /* read control */ 124 }; 125 126 /* read control register */ 127 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 128 dev_err(&client->dev, "%s: read error\n", __func__); 129 return -EIO; 130 } 131 132 return 0; 133 } 134 135 /* following are the sysfs callback functions */ 136 static ssize_t show_control(struct device *dev, struct device_attribute *attr, 137 char *buf) 138 { 139 struct i2c_client *client = to_i2c_client(dev); 140 u8 control; 141 int err; 142 143 err = ds1672_get_control(client, &control); 144 if (err) 145 return err; 146 147 return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC) 148 ? "disabled" : "enabled"); 149 } 150 151 static DEVICE_ATTR(control, S_IRUGO, show_control, NULL); 152 153 static const struct rtc_class_ops ds1672_rtc_ops = { 154 .read_time = ds1672_rtc_read_time, 155 .set_time = ds1672_rtc_set_time, 156 .set_mmss = ds1672_rtc_set_mmss, 157 }; 158 159 static int ds1672_remove(struct i2c_client *client) 160 { 161 struct rtc_device *rtc = i2c_get_clientdata(client); 162 163 if (rtc) 164 rtc_device_unregister(rtc); 165 166 return 0; 167 } 168 169 static int ds1672_probe(struct i2c_client *client, 170 const struct i2c_device_id *id) 171 { 172 int err = 0; 173 u8 control; 174 struct rtc_device *rtc; 175 176 dev_dbg(&client->dev, "%s\n", __func__); 177 178 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 179 return -ENODEV; 180 181 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 182 183 rtc = rtc_device_register(ds1672_driver.driver.name, &client->dev, 184 &ds1672_rtc_ops, THIS_MODULE); 185 186 if (IS_ERR(rtc)) 187 return PTR_ERR(rtc); 188 189 i2c_set_clientdata(client, rtc); 190 191 /* read control register */ 192 err = ds1672_get_control(client, &control); 193 if (err) 194 goto exit_devreg; 195 196 if (control & DS1672_REG_CONTROL_EOSC) 197 dev_warn(&client->dev, "Oscillator not enabled. " 198 "Set time to enable.\n"); 199 200 /* Register sysfs hooks */ 201 err = device_create_file(&client->dev, &dev_attr_control); 202 if (err) 203 goto exit_devreg; 204 205 return 0; 206 207 exit_devreg: 208 rtc_device_unregister(rtc); 209 return err; 210 } 211 212 static struct i2c_driver ds1672_driver = { 213 .driver = { 214 .name = "rtc-ds1672", 215 }, 216 .probe = &ds1672_probe, 217 .remove = &ds1672_remove, 218 }; 219 220 static int __init ds1672_init(void) 221 { 222 return i2c_add_driver(&ds1672_driver); 223 } 224 225 static void __exit ds1672_exit(void) 226 { 227 i2c_del_driver(&ds1672_driver); 228 } 229 230 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 231 MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver"); 232 MODULE_LICENSE("GPL"); 233 MODULE_VERSION(DRV_VERSION); 234 235 module_init(ds1672_init); 236 module_exit(ds1672_exit); 237