Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 | /* * Driver for Epson RTC-9701JE * * Copyright (C) 2008 Magnus Damm * * Based on rtc-max6902.c * * Copyright (C) 2006 8D Technologies inc. * Copyright (C) 2004 Compulab Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/device.h> #include <linux/init.h> #include <linux/rtc.h> #include <linux/spi/spi.h> #include <linux/bcd.h> #include <linux/delay.h> #include <linux/bitops.h> #define RSECCNT 0x00 /* Second Counter */ #define RMINCNT 0x01 /* Minute Counter */ #define RHRCNT 0x02 /* Hour Counter */ #define RWKCNT 0x03 /* Week Counter */ #define RDAYCNT 0x04 /* Day Counter */ #define RMONCNT 0x05 /* Month Counter */ #define RYRCNT 0x06 /* Year Counter */ #define R100CNT 0x07 /* Y100 Counter */ #define RMINAR 0x08 /* Minute Alarm */ #define RHRAR 0x09 /* Hour Alarm */ #define RWKAR 0x0a /* Week/Day Alarm */ #define RTIMCNT 0x0c /* Interval Timer */ #define REXT 0x0d /* Extension Register */ #define RFLAG 0x0e /* RTC Flag Register */ #define RCR 0x0f /* RTC Control Register */ static int write_reg(struct device *dev, int address, unsigned char data) { struct spi_device *spi = to_spi_device(dev); unsigned char buf[2]; buf[0] = address & 0x7f; buf[1] = data; return spi_write(spi, buf, ARRAY_SIZE(buf)); } static int read_regs(struct device *dev, unsigned char *regs, int no_regs) { struct spi_device *spi = to_spi_device(dev); u8 txbuf[1], rxbuf[1]; int k, ret; ret = 0; for (k = 0; ret == 0 && k < no_regs; k++) { txbuf[0] = 0x80 | regs[k]; ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); regs[k] = rxbuf[0]; } return ret; } static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) { int ret; unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, RDAYCNT, RMONCNT, RYRCNT }; ret = read_regs(dev, buf, ARRAY_SIZE(buf)); if (ret) return ret; memset(dt, 0, sizeof(*dt)); dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */ dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */ dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */ dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */ dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */ dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */ /* the rtc device may contain illegal values on power up * according to the data sheet. make sure they are valid. */ return rtc_valid_tm(dt); } static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) { int ret, year; year = dt->tm_year + 1900; if (year >= 2100 || year < 2000) return -EINVAL; ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour)); ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min)); ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec)); ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday)); ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1)); ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100)); ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday); return ret; } static const struct rtc_class_ops r9701_rtc_ops = { .read_time = r9701_get_datetime, .set_time = r9701_set_datetime, }; static int r9701_probe(struct spi_device *spi) { struct rtc_device *rtc; struct rtc_time dt; unsigned char tmp; int res; tmp = R100CNT; res = read_regs(&spi->dev, &tmp, 1); if (res || tmp != 0x20) { dev_err(&spi->dev, "cannot read RTC register\n"); return -ENODEV; } /* * The device seems to be present. Now check if the registers * contain invalid values. If so, try to write a default date: * 2000/1/1 00:00:00 */ if (r9701_get_datetime(&spi->dev, &dt)) { dev_info(&spi->dev, "trying to repair invalid date/time\n"); dt.tm_sec = 0; dt.tm_min = 0; dt.tm_hour = 0; dt.tm_mday = 1; dt.tm_mon = 0; dt.tm_year = 100; if (r9701_set_datetime(&spi->dev, &dt) || r9701_get_datetime(&spi->dev, &dt)) { dev_err(&spi->dev, "cannot repair RTC register\n"); return -ENODEV; } } rtc = devm_rtc_device_register(&spi->dev, "r9701", &r9701_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); spi_set_drvdata(spi, rtc); return 0; } static int r9701_remove(struct spi_device *spi) { return 0; } static struct spi_driver r9701_driver = { .driver = { .name = "rtc-r9701", }, .probe = r9701_probe, .remove = r9701_remove, }; module_spi_driver(r9701_driver); MODULE_DESCRIPTION("r9701 spi RTC driver"); MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:rtc-r9701"); |