168 lines
4.1 KiB
C
168 lines
4.1 KiB
C
/*
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* Driver for Epson RTC-9701JE
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*
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* Copyright (C) 2008 Magnus Damm
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*
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* Based on rtc-max6902.c
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*
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* Copyright (C) 2006 8D Technologies inc.
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* Copyright (C) 2004 Compulab Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/rtc.h>
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#include <linux/spi/spi.h>
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#include <linux/bcd.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#define RSECCNT 0x00 /* Second Counter */
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#define RMINCNT 0x01 /* Minute Counter */
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#define RHRCNT 0x02 /* Hour Counter */
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#define RWKCNT 0x03 /* Week Counter */
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#define RDAYCNT 0x04 /* Day Counter */
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#define RMONCNT 0x05 /* Month Counter */
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#define RYRCNT 0x06 /* Year Counter */
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#define R100CNT 0x07 /* Y100 Counter */
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#define RMINAR 0x08 /* Minute Alarm */
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#define RHRAR 0x09 /* Hour Alarm */
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#define RWKAR 0x0a /* Week/Day Alarm */
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#define RTIMCNT 0x0c /* Interval Timer */
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#define REXT 0x0d /* Extension Register */
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#define RFLAG 0x0e /* RTC Flag Register */
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#define RCR 0x0f /* RTC Control Register */
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static int write_reg(struct device *dev, int address, unsigned char data)
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{
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struct spi_device *spi = to_spi_device(dev);
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unsigned char buf[2];
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buf[0] = address & 0x7f;
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buf[1] = data;
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return spi_write(spi, buf, ARRAY_SIZE(buf));
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}
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static int read_regs(struct device *dev, unsigned char *regs, int no_regs)
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{
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struct spi_device *spi = to_spi_device(dev);
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u8 txbuf[1], rxbuf[1];
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int k, ret;
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ret = 0;
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for (k = 0; ret == 0 && k < no_regs; k++) {
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txbuf[0] = 0x80 | regs[k];
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ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
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regs[k] = rxbuf[0];
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}
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return ret;
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}
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static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)
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{
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int ret;
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unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
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RDAYCNT, RMONCNT, RYRCNT };
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ret = read_regs(dev, buf, ARRAY_SIZE(buf));
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if (ret)
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return ret;
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memset(dt, 0, sizeof(*dt));
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dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
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dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
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dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */
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dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
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dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
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dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */
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/* the rtc device may contain illegal values on power up
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* according to the data sheet. make sure they are valid.
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*/
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return rtc_valid_tm(dt);
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}
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static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
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{
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int ret, year;
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year = dt->tm_year + 1900;
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if (year >= 2100 || year < 2000)
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return -EINVAL;
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ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
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ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
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ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
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ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
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ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
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ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
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ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);
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return ret;
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}
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static const struct rtc_class_ops r9701_rtc_ops = {
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.read_time = r9701_get_datetime,
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.set_time = r9701_set_datetime,
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};
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static int __devinit r9701_probe(struct spi_device *spi)
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{
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struct rtc_device *rtc;
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unsigned char tmp;
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int res;
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tmp = R100CNT;
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res = read_regs(&spi->dev, &tmp, 1);
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if (res || tmp != 0x20) {
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dev_err(&spi->dev, "cannot read RTC register\n");
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return -ENODEV;
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}
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rtc = rtc_device_register("r9701",
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&spi->dev, &r9701_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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dev_set_drvdata(&spi->dev, rtc);
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return 0;
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}
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static int __devexit r9701_remove(struct spi_device *spi)
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{
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struct rtc_device *rtc = dev_get_drvdata(&spi->dev);
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rtc_device_unregister(rtc);
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return 0;
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}
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static struct spi_driver r9701_driver = {
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.driver = {
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.name = "rtc-r9701",
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.owner = THIS_MODULE,
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},
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.probe = r9701_probe,
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.remove = __devexit_p(r9701_remove),
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};
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module_spi_driver(r9701_driver);
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MODULE_DESCRIPTION("r9701 spi RTC driver");
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MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("spi:rtc-r9701");
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