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/version.h> 18 #include <linux/kernel.h> 19 #include <linux/platform_device.h> 20 #include <linux/device.h> 21 #include <linux/init.h> 22 #include <linux/rtc.h> 23 #include <linux/spi/spi.h> 24 #include <linux/bcd.h> 25 #include <linux/delay.h> 26 #include <linux/bitops.h> 27 28 #define RSECCNT 0x00 /* Second Counter */ 29 #define RMINCNT 0x01 /* Minute Counter */ 30 #define RHRCNT 0x02 /* Hour Counter */ 31 #define RWKCNT 0x03 /* Week Counter */ 32 #define RDAYCNT 0x04 /* Day Counter */ 33 #define RMONCNT 0x05 /* Month Counter */ 34 #define RYRCNT 0x06 /* Year Counter */ 35 #define R100CNT 0x07 /* Y100 Counter */ 36 #define RMINAR 0x08 /* Minute Alarm */ 37 #define RHRAR 0x09 /* Hour Alarm */ 38 #define RWKAR 0x0a /* Week/Day Alarm */ 39 #define RTIMCNT 0x0c /* Interval Timer */ 40 #define REXT 0x0d /* Extension Register */ 41 #define RFLAG 0x0e /* RTC Flag Register */ 42 #define RCR 0x0f /* RTC Control Register */ 43 44 static int write_reg(struct device *dev, int address, unsigned char data) 45 { 46 struct spi_device *spi = to_spi_device(dev); 47 unsigned char buf[2]; 48 49 buf[0] = address & 0x7f; 50 buf[1] = data; 51 52 return spi_write(spi, buf, ARRAY_SIZE(buf)); 53 } 54 55 static int read_regs(struct device *dev, unsigned char *regs, int no_regs) 56 { 57 struct spi_device *spi = to_spi_device(dev); 58 u8 txbuf[1], rxbuf[1]; 59 int k, ret; 60 61 ret = 0; 62 63 for (k = 0; ret == 0 && k < no_regs; k++) { 64 txbuf[0] = 0x80 | regs[k]; 65 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 66 regs[k] = rxbuf[0]; 67 } 68 69 return ret; 70 } 71 72 static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) 73 { 74 unsigned long time; 75 int ret; 76 unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, 77 RDAYCNT, RMONCNT, RYRCNT }; 78 79 ret = read_regs(dev, buf, ARRAY_SIZE(buf)); 80 if (ret) 81 return ret; 82 83 memset(dt, 0, sizeof(*dt)); 84 85 dt->tm_sec = BCD2BIN(buf[0]); /* RSECCNT */ 86 dt->tm_min = BCD2BIN(buf[1]); /* RMINCNT */ 87 dt->tm_hour = BCD2BIN(buf[2]); /* RHRCNT */ 88 89 dt->tm_mday = BCD2BIN(buf[3]); /* RDAYCNT */ 90 dt->tm_mon = BCD2BIN(buf[4]) - 1; /* RMONCNT */ 91 dt->tm_year = BCD2BIN(buf[5]) + 100; /* RYRCNT */ 92 93 /* the rtc device may contain illegal values on power up 94 * according to the data sheet. make sure they are valid. 95 */ 96 97 return rtc_valid_tm(dt); 98 } 99 100 static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) 101 { 102 int ret, year; 103 104 year = dt->tm_year + 1900; 105 if (year >= 2100 || year < 2000) 106 return -EINVAL; 107 108 ret = write_reg(dev, RHRCNT, BIN2BCD(dt->tm_hour)); 109 ret = ret ? ret : write_reg(dev, RMINCNT, BIN2BCD(dt->tm_min)); 110 ret = ret ? ret : write_reg(dev, RSECCNT, BIN2BCD(dt->tm_sec)); 111 ret = ret ? ret : write_reg(dev, RDAYCNT, BIN2BCD(dt->tm_mday)); 112 ret = ret ? ret : write_reg(dev, RMONCNT, BIN2BCD(dt->tm_mon + 1)); 113 ret = ret ? ret : write_reg(dev, RYRCNT, BIN2BCD(dt->tm_year - 100)); 114 ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday); 115 116 return ret; 117 } 118 119 static const struct rtc_class_ops r9701_rtc_ops = { 120 .read_time = r9701_get_datetime, 121 .set_time = r9701_set_datetime, 122 }; 123 124 static int __devinit r9701_probe(struct spi_device *spi) 125 { 126 struct rtc_device *rtc; 127 unsigned char tmp; 128 int res; 129 130 rtc = rtc_device_register("r9701", 131 &spi->dev, &r9701_rtc_ops, THIS_MODULE); 132 if (IS_ERR(rtc)) 133 return PTR_ERR(rtc); 134 135 dev_set_drvdata(&spi->dev, rtc); 136 137 tmp = R100CNT; 138 res = read_regs(&spi->dev, &tmp, 1); 139 if (res || tmp != 0x20) { 140 rtc_device_unregister(rtc); 141 return res; 142 } 143 144 return 0; 145 } 146 147 static int __devexit r9701_remove(struct spi_device *spi) 148 { 149 struct rtc_device *rtc = dev_get_drvdata(&spi->dev); 150 151 rtc_device_unregister(rtc); 152 return 0; 153 } 154 155 static struct spi_driver r9701_driver = { 156 .driver = { 157 .name = "rtc-r9701", 158 .owner = THIS_MODULE, 159 }, 160 .probe = r9701_probe, 161 .remove = __devexit_p(r9701_remove), 162 }; 163 164 static __init int r9701_init(void) 165 { 166 return spi_register_driver(&r9701_driver); 167 } 168 module_init(r9701_init); 169 170 static __exit void r9701_exit(void) 171 { 172 spi_unregister_driver(&r9701_driver); 173 } 174 module_exit(r9701_exit); 175 176 MODULE_DESCRIPTION("r9701 spi RTC driver"); 177 MODULE_AUTHOR("Magnus Damm <[email protected]>"); 178 MODULE_LICENSE("GPL"); 179