1/* 2 * Driver for TI BQ32000 RTC. 3 * 4 * Copyright (C) 2009 Semihalf. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11#include <linux/module.h> 12#include <linux/i2c.h> 13#include <linux/rtc.h> 14#include <linux/init.h> 15#include <linux/errno.h> 16#include <linux/bcd.h> 17 18#define BQ32K_SECONDS 0x00 /* Seconds register address */ 19#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ 20#define BQ32K_STOP 0x80 /* Oscillator Stop flat */ 21 22#define BQ32K_MINUTES 0x01 /* Minutes register address */ 23#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ 24#define BQ32K_OF 0x80 /* Oscillator Failure flag */ 25 26#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ 27#define BQ32K_CENT 0x40 /* Century flag */ 28#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ 29 30struct bq32k_regs { 31 uint8_t seconds; 32 uint8_t minutes; 33 uint8_t cent_hours; 34 uint8_t day; 35 uint8_t date; 36 uint8_t month; 37 uint8_t years; 38}; 39 40static struct i2c_driver bq32k_driver; 41 42static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) 43{ 44 struct i2c_client *client = to_i2c_client(dev); 45 struct i2c_msg msgs[] = { 46 { 47 .addr = client->addr, 48 .flags = 0, 49 .len = 1, 50 .buf = &off, 51 }, { 52 .addr = client->addr, 53 .flags = I2C_M_RD, 54 .len = len, 55 .buf = data, 56 } 57 }; 58 59 if (i2c_transfer(client->adapter, msgs, 2) == 2) 60 return 0; 61 62 return -EIO; 63} 64 65static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) 66{ 67 struct i2c_client *client = to_i2c_client(dev); 68 uint8_t buffer[len + 1]; 69 70 buffer[0] = off; 71 memcpy(&buffer[1], data, len); 72 73 if (i2c_master_send(client, buffer, len + 1) == len + 1) 74 return 0; 75 76 return -EIO; 77} 78 79static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) 80{ 81 struct bq32k_regs regs; 82 int error; 83 84 error = bq32k_read(dev, ®s, 0, sizeof(regs)); 85 if (error) 86 return error; 87 88 tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); 89 tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK); 90 tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); 91 tm->tm_mday = bcd2bin(regs.date); 92 tm->tm_wday = bcd2bin(regs.day) - 1; 93 tm->tm_mon = bcd2bin(regs.month) - 1; 94 tm->tm_year = bcd2bin(regs.years) + 95 ((regs.cent_hours & BQ32K_CENT) ? 100 : 0); 96 97 return rtc_valid_tm(tm); 98} 99 100static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) 101{ 102 struct bq32k_regs regs; 103 104 regs.seconds = bin2bcd(tm->tm_sec); 105 regs.minutes = bin2bcd(tm->tm_min); 106 regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; 107 regs.day = bin2bcd(tm->tm_wday + 1); 108 regs.date = bin2bcd(tm->tm_mday); 109 regs.month = bin2bcd(tm->tm_mon + 1); 110 111 if (tm->tm_year >= 100) { 112 regs.cent_hours |= BQ32K_CENT; 113 regs.years = bin2bcd(tm->tm_year - 100); 114 } else 115 regs.years = bin2bcd(tm->tm_year); 116 117 return bq32k_write(dev, ®s, 0, sizeof(regs)); 118} 119 120static const struct rtc_class_ops bq32k_rtc_ops = { 121 .read_time = bq32k_rtc_read_time, 122 .set_time = bq32k_rtc_set_time, 123}; 124 125static int bq32k_probe(struct i2c_client *client, 126 const struct i2c_device_id *id) 127{ 128 struct device *dev = &client->dev; 129 struct rtc_device *rtc; 130 uint8_t reg; 131 int error; 132 133 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 134 return -ENODEV; 135 136 /* Check Oscillator Stop flag */ 137 error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); 138 if (!error && (reg & BQ32K_STOP)) { 139 dev_warn(dev, "Oscillator was halted. Restarting...\n"); 140 reg &= ~BQ32K_STOP; 141 error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); 142 } 143 if (error) 144 return error; 145 146 /* Check Oscillator Failure flag */ 147 error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); 148 if (!error && (reg & BQ32K_OF)) { 149 dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); 150 reg &= ~BQ32K_OF; 151 error = bq32k_write(dev, ®, BQ32K_MINUTES, 1); 152 } 153 if (error) 154 return error; 155 156 rtc = rtc_device_register(bq32k_driver.driver.name, &client->dev, 157 &bq32k_rtc_ops, THIS_MODULE); 158 if (IS_ERR(rtc)) 159 return PTR_ERR(rtc); 160 161 i2c_set_clientdata(client, rtc); 162 163 return 0; 164} 165 166static int __devexit bq32k_remove(struct i2c_client *client) 167{ 168 struct rtc_device *rtc = i2c_get_clientdata(client); 169 170 rtc_device_unregister(rtc); 171 return 0; 172} 173 174static const struct i2c_device_id bq32k_id[] = { 175 { "bq32000", 0 }, 176 { } 177}; 178MODULE_DEVICE_TABLE(i2c, bq32k_id); 179 180static struct i2c_driver bq32k_driver = { 181 .driver = { 182 .name = "bq32k", 183 .owner = THIS_MODULE, 184 }, 185 .probe = bq32k_probe, 186 .remove = __devexit_p(bq32k_remove), 187 .id_table = bq32k_id, 188}; 189 190static __init int bq32k_init(void) 191{ 192 return i2c_add_driver(&bq32k_driver); 193} 194module_init(bq32k_init); 195 196static __exit void bq32k_exit(void) 197{ 198 i2c_del_driver(&bq32k_driver); 199} 200module_exit(bq32k_exit); 201 202MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>"); 203MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); 204MODULE_LICENSE("GPL"); 205