/* * 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");