mirror of https://gitee.com/openkylin/linux.git
149 lines
3.8 KiB
C
149 lines
3.8 KiB
C
/*
|
|
* Driver for ST M41T94 SPI RTC
|
|
*
|
|
* Copyright (C) 2008 Kim B. Heino
|
|
*
|
|
* 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/rtc.h>
|
|
#include <linux/spi/spi.h>
|
|
#include <linux/bcd.h>
|
|
|
|
#define M41T94_REG_SECONDS 0x01
|
|
#define M41T94_REG_MINUTES 0x02
|
|
#define M41T94_REG_HOURS 0x03
|
|
#define M41T94_REG_WDAY 0x04
|
|
#define M41T94_REG_DAY 0x05
|
|
#define M41T94_REG_MONTH 0x06
|
|
#define M41T94_REG_YEAR 0x07
|
|
#define M41T94_REG_HT 0x0c
|
|
|
|
#define M41T94_BIT_HALT 0x40
|
|
#define M41T94_BIT_STOP 0x80
|
|
#define M41T94_BIT_CB 0x40
|
|
#define M41T94_BIT_CEB 0x80
|
|
|
|
static int m41t94_set_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct spi_device *spi = to_spi_device(dev);
|
|
u8 buf[8]; /* write cmd + 7 registers */
|
|
|
|
dev_dbg(dev, "%s secs=%d, mins=%d, "
|
|
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
|
|
"write", tm->tm_sec, tm->tm_min,
|
|
tm->tm_hour, tm->tm_mday,
|
|
tm->tm_mon, tm->tm_year, tm->tm_wday);
|
|
|
|
buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */
|
|
buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec);
|
|
buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min);
|
|
buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour);
|
|
buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1);
|
|
buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday);
|
|
buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1);
|
|
|
|
buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB;
|
|
if (tm->tm_year >= 100)
|
|
buf[M41T94_REG_HOURS] |= M41T94_BIT_CB;
|
|
buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100);
|
|
|
|
return spi_write(spi, buf, 8);
|
|
}
|
|
|
|
static int m41t94_read_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct spi_device *spi = to_spi_device(dev);
|
|
u8 buf[2];
|
|
int ret, hour;
|
|
|
|
/* clear halt update bit */
|
|
ret = spi_w8r8(spi, M41T94_REG_HT);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret & M41T94_BIT_HALT) {
|
|
buf[0] = 0x80 | M41T94_REG_HT;
|
|
buf[1] = ret & ~M41T94_BIT_HALT;
|
|
spi_write(spi, buf, 2);
|
|
}
|
|
|
|
/* clear stop bit */
|
|
ret = spi_w8r8(spi, M41T94_REG_SECONDS);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret & M41T94_BIT_STOP) {
|
|
buf[0] = 0x80 | M41T94_REG_SECONDS;
|
|
buf[1] = ret & ~M41T94_BIT_STOP;
|
|
spi_write(spi, buf, 2);
|
|
}
|
|
|
|
tm->tm_sec = bcd2bin(spi_w8r8(spi, M41T94_REG_SECONDS));
|
|
tm->tm_min = bcd2bin(spi_w8r8(spi, M41T94_REG_MINUTES));
|
|
hour = spi_w8r8(spi, M41T94_REG_HOURS);
|
|
tm->tm_hour = bcd2bin(hour & 0x3f);
|
|
tm->tm_wday = bcd2bin(spi_w8r8(spi, M41T94_REG_WDAY)) - 1;
|
|
tm->tm_mday = bcd2bin(spi_w8r8(spi, M41T94_REG_DAY));
|
|
tm->tm_mon = bcd2bin(spi_w8r8(spi, M41T94_REG_MONTH)) - 1;
|
|
tm->tm_year = bcd2bin(spi_w8r8(spi, M41T94_REG_YEAR));
|
|
if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB))
|
|
tm->tm_year += 100;
|
|
|
|
dev_dbg(dev, "%s secs=%d, mins=%d, "
|
|
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
|
|
"read", tm->tm_sec, tm->tm_min,
|
|
tm->tm_hour, tm->tm_mday,
|
|
tm->tm_mon, tm->tm_year, tm->tm_wday);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct rtc_class_ops m41t94_rtc_ops = {
|
|
.read_time = m41t94_read_time,
|
|
.set_time = m41t94_set_time,
|
|
};
|
|
|
|
static struct spi_driver m41t94_driver;
|
|
|
|
static int m41t94_probe(struct spi_device *spi)
|
|
{
|
|
struct rtc_device *rtc;
|
|
int res;
|
|
|
|
spi->bits_per_word = 8;
|
|
spi_setup(spi);
|
|
|
|
res = spi_w8r8(spi, M41T94_REG_SECONDS);
|
|
if (res < 0) {
|
|
dev_err(&spi->dev, "not found.\n");
|
|
return res;
|
|
}
|
|
|
|
rtc = devm_rtc_device_register(&spi->dev, m41t94_driver.driver.name,
|
|
&m41t94_rtc_ops, THIS_MODULE);
|
|
if (IS_ERR(rtc))
|
|
return PTR_ERR(rtc);
|
|
|
|
spi_set_drvdata(spi, rtc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct spi_driver m41t94_driver = {
|
|
.driver = {
|
|
.name = "rtc-m41t94",
|
|
},
|
|
.probe = m41t94_probe,
|
|
};
|
|
|
|
module_spi_driver(m41t94_driver);
|
|
|
|
MODULE_AUTHOR("Kim B. Heino <Kim.Heino@bluegiga.com>");
|
|
MODULE_DESCRIPTION("Driver for ST M41T94 SPI RTC");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("spi:rtc-m41t94");
|