| /* |
| * 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 __devinit 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)) { |
| dev_err(&spi->dev, "cannot repair RTC register\n"); |
| return -ENODEV; |
| } |
| } |
| |
| rtc = rtc_device_register("r9701", |
| &spi->dev, &r9701_rtc_ops, THIS_MODULE); |
| if (IS_ERR(rtc)) |
| return PTR_ERR(rtc); |
| |
| dev_set_drvdata(&spi->dev, rtc); |
| |
| return 0; |
| } |
| |
| static int __devexit r9701_remove(struct spi_device *spi) |
| { |
| struct rtc_device *rtc = dev_get_drvdata(&spi->dev); |
| |
| rtc_device_unregister(rtc); |
| return 0; |
| } |
| |
| static struct spi_driver r9701_driver = { |
| .driver = { |
| .name = "rtc-r9701", |
| .owner = THIS_MODULE, |
| }, |
| .probe = r9701_probe, |
| .remove = __devexit_p(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"); |