rtc: add support for ST M41T94 SPI RTC (8fc2c767) · Commits · 戴 / test

drivers/rtc/Kconfig

+9 −0

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		@@ -273,6 +273,15 @@ comment "SPI RTC drivers"

		if SPI_MASTER

		config RTC_DRV_M41T94
		tristate "ST M41T94"
		help
		If you say yes here you will get support for the
		ST M41T94 SPI RTC chip.

		This driver can also be built as a module. If so, the module
		will be called rtc-m41t94.

		config RTC_DRV_MAX6902
		tristate "Maxim MAX6902"
		help

drivers/rtc/Makefile

+1 −0

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		@@ -34,6 +34,7 @@ obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
		obj-$(CONFIG_RTC_DRV_FM3130) += rtc-fm3130.o
		obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
		obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
		obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
		obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
		obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
		obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o

drivers/rtc/rtc-m41t94.c

0 → 100644

+173 −0

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		/*
		* 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);

		/* initial clock setting can be undefined */
		return rtc_valid_tm(tm);
		}

		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 __devinit 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 = rtc_device_register(m41t94_driver.driver.name,
		&spi->dev, &m41t94_rtc_ops, THIS_MODULE);
		if (IS_ERR(rtc))
		return PTR_ERR(rtc);

		dev_set_drvdata(&spi->dev, rtc);

		return 0;
		}

		static int __devexit m41t94_remove(struct spi_device *spi)
		{
		struct rtc_device *rtc = platform_get_drvdata(spi);

		if (rtc)
		rtc_device_unregister(rtc);

		return 0;
		}

		static struct spi_driver m41t94_driver = {
		.driver = {
		.name = "rtc-m41t94",
		.bus = &spi_bus_type,
		.owner = THIS_MODULE,
		},
		.probe = m41t94_probe,
		.remove = __devexit_p(m41t94_remove),
		};

		static __init int m41t94_init(void)
		{
		return spi_register_driver(&m41t94_driver);
		}

		module_init(m41t94_init);

		static __exit void m41t94_exit(void)
		{
		spi_unregister_driver(&m41t94_driver);
		}

		module_exit(m41t94_exit);

		MODULE_AUTHOR("Kim B. Heino <Kim.Heino@bluegiga.com>");
		MODULE_DESCRIPTION("Driver for ST M41T94 SPI RTC");
		MODULE_LICENSE("GPL");

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