1 /* 2 * Driver for Epson RTC-9701JE 3 * 4 * Copyright (C) 2008 Magnus Damm 5 * 6 * Based on rtc-max6902.c 7 * 8 * Copyright (C) 2006 8D Technologies inc. 9 * Copyright (C) 2004 Compulab Ltd. 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/module.h> 17 #include <linux/kernel.h> 18 #include <linux/platform_device.h> 19 #include <linux/device.h> 20 #include <linux/init.h> 21 #include <linux/rtc.h> 22 #include <linux/spi/spi.h> 23 #include <linux/bcd.h> 24 #include <linux/delay.h> 25 #include <linux/bitops.h> 26 27 #define RSECCNT 0x00 /* Second Counter */ 28 #define RMINCNT 0x01 /* Minute Counter */ 29 #define RHRCNT 0x02 /* Hour Counter */ 30 #define RWKCNT 0x03 /* Week Counter */ 31 #define RDAYCNT 0x04 /* Day Counter */ 32 #define RMONCNT 0x05 /* Month Counter */ 33 #define RYRCNT 0x06 /* Year Counter */ 34 #define R100CNT 0x07 /* Y100 Counter */ 35 #define RMINAR 0x08 /* Minute Alarm */ 36 #define RHRAR 0x09 /* Hour Alarm */ 37 #define RWKAR 0x0a /* Week/Day Alarm */ 38 #define RTIMCNT 0x0c /* Interval Timer */ 39 #define REXT 0x0d /* Extension Register */ 40 #define RFLAG 0x0e /* RTC Flag Register */ 41 #define RCR 0x0f /* RTC Control Register */ 42 43 static int write_reg(struct device *dev, int address, unsigned char data) 44 { 45 struct spi_device *spi = to_spi_device(dev); 46 unsigned char buf[2]; 47 48 buf[0] = address & 0x7f; 49 buf[1] = data; 50 51 return spi_write(spi, buf, ARRAY_SIZE(buf)); 52 } 53 54 static int read_regs(struct device *dev, unsigned char *regs, int no_regs) 55 { 56 struct spi_device *spi = to_spi_device(dev); 57 u8 txbuf[1], rxbuf[1]; 58 int k, ret; 59 60 ret = 0; 61 62 for (k = 0; ret == 0 && k < no_regs; k++) { 63 txbuf[0] = 0x80 | regs[k]; 64 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 65 regs[k] = rxbuf[0]; 66 } 67 68 return ret; 69 } 70 71 static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) 72 { 73 int ret; 74 unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, 75 RDAYCNT, RMONCNT, RYRCNT }; 76 77 ret = read_regs(dev, buf, ARRAY_SIZE(buf)); 78 if (ret) 79 return ret; 80 81 memset(dt, 0, sizeof(*dt)); 82 83 dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */ 84 dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */ 85 dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */ 86 87 dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */ 88 dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */ 89 dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */ 90 91 /* the rtc device may contain illegal values on power up 92 * according to the data sheet. make sure they are valid. 93 */ 94 95 return rtc_valid_tm(dt); 96 } 97 98 static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) 99 { 100 int ret, year; 101 102 year = dt->tm_year + 1900; 103 if (year >= 2100 || year < 2000) 104 return -EINVAL; 105 106 ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour)); 107 ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min)); 108 ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec)); 109 ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday)); 110 ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1)); 111 ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100)); 112 ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday); 113 114 return ret; 115 } 116 117 static const struct rtc_class_ops r9701_rtc_ops = { 118 .read_time = r9701_get_datetime, 119 .set_time = r9701_set_datetime, 120 }; 121 122 static int __devinit r9701_probe(struct spi_device *spi) 123 { 124 struct rtc_device *rtc; 125 unsigned char tmp; 126 int res; 127 128 rtc = rtc_device_register("r9701", 129 &spi->dev, &r9701_rtc_ops, THIS_MODULE); 130 if (IS_ERR(rtc)) 131 return PTR_ERR(rtc); 132 133 dev_set_drvdata(&spi->dev, rtc); 134 135 tmp = R100CNT; 136 res = read_regs(&spi->dev, &tmp, 1); 137 if (res || tmp != 0x20) { 138 rtc_device_unregister(rtc); 139 return res; 140 } 141 142 return 0; 143 } 144 145 static int __devexit r9701_remove(struct spi_device *spi) 146 { 147 struct rtc_device *rtc = dev_get_drvdata(&spi->dev); 148 149 rtc_device_unregister(rtc); 150 return 0; 151 } 152 153 static struct spi_driver r9701_driver = { 154 .driver = { 155 .name = "rtc-r9701", 156 .owner = THIS_MODULE, 157 }, 158 .probe = r9701_probe, 159 .remove = __devexit_p(r9701_remove), 160 }; 161 162 static __init int r9701_init(void) 163 { 164 return spi_register_driver(&r9701_driver); 165 } 166 module_init(r9701_init); 167 168 static __exit void r9701_exit(void) 169 { 170 spi_unregister_driver(&r9701_driver); 171 } 172 module_exit(r9701_exit); 173 174 MODULE_DESCRIPTION("r9701 spi RTC driver"); 175 MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); 176 MODULE_LICENSE("GPL"); 177 MODULE_ALIAS("spi:rtc-r9701"); 178