1 /* drivers/rtc/rtc-r9701.c 2 * 3 * Driver for Epson RTC-9701JE 4 * 5 * Copyright (C) 2008 Magnus Damm 6 * 7 * Based on drivers/rtc/rtc-max6902.c 8 * 9 * Copyright (C) 2006 8D Technologies inc. 10 * Copyright (C) 2004 Compulab Ltd. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <linux/module.h> 18 #include <linux/version.h> 19 #include <linux/kernel.h> 20 #include <linux/platform_device.h> 21 #include <linux/device.h> 22 #include <linux/init.h> 23 #include <linux/rtc.h> 24 #include <linux/spi/spi.h> 25 #include <linux/bcd.h> 26 #include <linux/delay.h> 27 #include <linux/bitops.h> 28 29 #define RSECCNT 0x00 /* Second Counter */ 30 #define RMINCNT 0x01 /* Minute Counter */ 31 #define RHRCNT 0x02 /* Hour Counter */ 32 #define RWKCNT 0x03 /* Week Counter */ 33 #define RDAYCNT 0x04 /* Day Counter */ 34 #define RMONCNT 0x05 /* Month Counter */ 35 #define RYRCNT 0x06 /* Year Counter */ 36 #define R100CNT 0x07 /* Y100 Counter */ 37 #define RMINAR 0x08 /* Minute Alarm */ 38 #define RHRAR 0x09 /* Hour Alarm */ 39 #define RWKAR 0x0a /* Week/Day Alarm */ 40 #define RTIMCNT 0x0c /* Interval Timer */ 41 #define REXT 0x0d /* Extension Register */ 42 #define RFLAG 0x0e /* RTC Flag Register */ 43 #define RCR 0x0f /* RTC Control Register */ 44 45 static int write_reg(struct device *dev, int address, unsigned char data) 46 { 47 struct spi_device *spi = to_spi_device(dev); 48 unsigned char buf[2]; 49 50 buf[0] = address & 0x7f; 51 buf[1] = data; 52 53 return spi_write(spi, buf, ARRAY_SIZE(buf)); 54 } 55 56 static int read_regs(struct device *dev, unsigned char *regs, int no_regs) 57 { 58 struct spi_device *spi = to_spi_device(dev); 59 u8 txbuf[1], rxbuf[1]; 60 int k, ret; 61 62 ret = 0; 63 64 for (k = 0; ret == 0 && k < no_regs; k++) { 65 txbuf[0] = 0x80 | regs[k]; 66 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 67 regs[k] = rxbuf[0]; 68 } 69 70 return ret; 71 } 72 73 static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) 74 { 75 struct spi_device *spi = to_spi_device(dev); 76 unsigned long time; 77 int ret; 78 unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, 79 RDAYCNT, RMONCNT, RYRCNT }; 80 81 ret = read_regs(&spi->dev, buf, ARRAY_SIZE(buf)); 82 if (ret) 83 return ret; 84 85 memset(dt, 0, sizeof(*dt)); 86 87 dt->tm_sec = BCD2BIN(buf[0]); /* RSECCNT */ 88 dt->tm_min = BCD2BIN(buf[1]); /* RMINCNT */ 89 dt->tm_hour = BCD2BIN(buf[2]); /* RHRCNT */ 90 91 dt->tm_mday = BCD2BIN(buf[3]); /* RDAYCNT */ 92 dt->tm_mon = BCD2BIN(buf[4]) - 1; /* RMONCNT */ 93 dt->tm_year = BCD2BIN(buf[5]) + 100; /* RYRCNT */ 94 95 /* the rtc device may contain illegal values on power up 96 * according to the data sheet. make sure they are valid. 97 */ 98 99 ret = rtc_valid_tm(dt); 100 if (ret) 101 return ret; 102 103 /* don't bother with yday, wday and isdst. 104 * let the rtc core calculate them for us. 105 */ 106 107 rtc_tm_to_time(dt, &time); 108 rtc_time_to_tm(time, dt); 109 return 0; 110 } 111 112 static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) 113 { 114 int ret, year; 115 116 year = dt->tm_year + 1900; 117 if (year >= 2100 || year < 2000) 118 return -EINVAL; 119 120 ret = write_reg(dev, RHRCNT, BIN2BCD(dt->tm_hour)); 121 ret |= write_reg(dev, RMINCNT, BIN2BCD(dt->tm_min)); 122 ret |= write_reg(dev, RSECCNT, BIN2BCD(dt->tm_sec)); 123 ret |= write_reg(dev, RDAYCNT, BIN2BCD(dt->tm_mday)); 124 ret |= write_reg(dev, RMONCNT, BIN2BCD(dt->tm_mon + 1)); 125 ret |= write_reg(dev, RYRCNT, BIN2BCD(dt->tm_year - 100)); 126 ret |= write_reg(dev, RWKCNT, 1 << dt->tm_wday); 127 128 return ret; 129 } 130 131 static const struct rtc_class_ops r9701_rtc_ops = { 132 .read_time = r9701_get_datetime, 133 .set_time = r9701_set_datetime, 134 }; 135 136 static int __devinit r9701_probe(struct spi_device *spi) 137 { 138 struct rtc_device *rtc; 139 unsigned char tmp; 140 int res; 141 142 rtc = rtc_device_register("r9701", 143 &spi->dev, &r9701_rtc_ops, THIS_MODULE); 144 if (IS_ERR(rtc)) 145 return PTR_ERR(rtc); 146 147 dev_set_drvdata(&spi->dev, rtc); 148 149 spi->mode = SPI_MODE_3; 150 spi->bits_per_word = 8; 151 spi_setup(spi); 152 153 tmp = R100CNT; 154 res = read_regs(&spi->dev, &tmp, 1); 155 if (res || tmp != 0x20) { 156 rtc_device_unregister(rtc); 157 return res; 158 } 159 160 return 0; 161 } 162 163 static int __devexit r9701_remove(struct spi_device *spi) 164 { 165 struct rtc_device *rtc = dev_get_drvdata(&spi->dev); 166 167 rtc_device_unregister(rtc); 168 return 0; 169 } 170 171 static struct spi_driver r9701_driver = { 172 .driver = { 173 .name = "rtc-r9701", 174 .bus = &spi_bus_type, 175 .owner = THIS_MODULE, 176 }, 177 .probe = r9701_probe, 178 .remove = __devexit_p(r9701_remove), 179 }; 180 181 static __init int r9701_init(void) 182 { 183 return spi_register_driver(&r9701_driver); 184 } 185 module_init(r9701_init); 186 187 static __exit void r9701_exit(void) 188 { 189 spi_unregister_driver(&r9701_driver); 190 } 191 module_exit(r9701_exit); 192 193 MODULE_DESCRIPTION("r9701 spi RTC driver"); 194 MODULE_AUTHOR("Magnus Damm <[email protected]>"); 195 MODULE_LICENSE("GPL"); 196