[PATCH] Add max6902 RTC support (8e12ecc2) · Commits · 戴 / test

drivers/rtc/Kconfig

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		@@ -217,4 +217,14 @@ config RTC_DRV_TEST
		This driver can also be built as a module. If so, the module
		will be called rtc-test.

		config RTC_DRV_MAX6902
		tristate "Maxim 6902"
		depends on RTC_CLASS && SPI
		help
		If you say yes here you will get support for the
		Maxim MAX6902 spi RTC chip.

		This driver can also be built as a module. If so, the module
		will be called rtc-max6902.

		endmenu

drivers/rtc/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -23,3 +23,4 @@ obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
		obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
		obj-$(CONFIG_RTC_DRV_VR41XX) += rtc-vr41xx.o
		obj-$(CONFIG_RTC_DRV_PL031) += rtc-pl031.o
		obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o

drivers/rtc/rtc-max6902.c

0 → 100644

+286 −0

Original line number	Diff line number	Diff line
		/* drivers/char/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.
		*
		* Driver for MAX6902 spi RTC
		*
		* Changelog:
		*
		* 24-May-2006: Raphael Assenat <raph@8d.com>
		* - Major rework
		* Converted to rtc_device and uses the SPI layer.
		*
		* ??-???-2005: Someone at Compulab
		* - Initial driver creation.
		*/

		#include <linux/config.h>
		#include <linux/module.h>
		#include <linux/version.h>

		#include <linux/kernel.h>
		#include <linux/platform_device.h>
		#include <linux/init.h>
		#include <linux/rtc.h>
		#include <linux/spi/spi.h>
		#include <linux/bcd.h>
		#include <linux/delay.h>

		#define MAX6902_REG_SECONDS 0x01
		#define MAX6902_REG_MINUTES 0x03
		#define MAX6902_REG_HOURS 0x05
		#define MAX6902_REG_DATE 0x07
		#define MAX6902_REG_MONTH 0x09
		#define MAX6902_REG_DAY 0x0B
		#define MAX6902_REG_YEAR 0x0D
		#define MAX6902_REG_CONTROL 0x0F
		#define MAX6902_REG_CENTURY 0x13

		#undef MAX6902_DEBUG

		struct max6902 {
		struct rtc_device *rtc;
		u8 buf[9]; /* Burst read cmd + 8 registers */
		u8 tx_buf[2];
		u8 rx_buf[2];
		};

		static void max6902_set_reg(struct device *dev, unsigned char address,
		unsigned char data)
		{
		struct spi_device *spi = to_spi_device(dev);
		unsigned char buf[2];

		/* MSB must be '0' to write */
		buf[0] = address & 0x7f;
		buf[1] = data;

		spi_write(spi, buf, 2);
		}

		static int max6902_get_reg(struct device *dev, unsigned char address,
		unsigned char *data)
		{
		struct spi_device *spi = to_spi_device(dev);
		struct max6902 *chip = dev_get_drvdata(dev);
		struct spi_message message;
		struct spi_transfer xfer;
		int status;

		if (!data)
		return -EINVAL;

		/* Build our spi message */
		spi_message_init(&message);
		memset(&xfer, 0, sizeof(xfer));
		xfer.len = 2;
		/* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
		xfer.tx_buf = chip->tx_buf;
		xfer.rx_buf = chip->rx_buf;

		/* Set MSB to indicate read */
		chip->tx_buf[0] = address \| 0x80;

		spi_message_add_tail(&xfer, &message);

		/* do the i/o */
		status = spi_sync(spi, &message);
		if (status == 0)
		status = message.status;
		else
		return status;

		*data = chip->rx_buf[1];

		return status;
		}

		static int max6902_get_datetime(struct device dev, struct rtc_time dt)
		{
		unsigned char tmp;
		int century;
		int err;
		struct spi_device *spi = to_spi_device(dev);
		struct max6902 *chip = dev_get_drvdata(dev);
		struct spi_message message;
		struct spi_transfer xfer;
		int status;

		err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp);
		if (err)
		return err;

		/* build the message */
		spi_message_init(&message);
		memset(&xfer, 0, sizeof(xfer));
		xfer.len = 1 + 7; /* Burst read command + 7 registers */
		xfer.tx_buf = chip->buf;
		xfer.rx_buf = chip->buf;
		chip->buf[0] = 0xbf; /* Burst read */
		spi_message_add_tail(&xfer, &message);

		/* do the i/o */
		status = spi_sync(spi, &message);
		if (status == 0)
		status = message.status;
		else
		return status;

		/* The chip sends data in this order:
		* Seconds, Minutes, Hours, Date, Month, Day, Year */
		dt->tm_sec = BCD2BIN(chip->buf[1]);
		dt->tm_min = BCD2BIN(chip->buf[2]);
		dt->tm_hour = BCD2BIN(chip->buf[3]);
		dt->tm_mday = BCD2BIN(chip->buf[4]);
		dt->tm_mon = BCD2BIN(chip->buf[5] - 1);
		dt->tm_wday = BCD2BIN(chip->buf[6]);
		dt->tm_year = BCD2BIN(chip->buf[7]);

		century = BCD2BIN(tmp) * 100;

		dt->tm_year += century;
		dt->tm_year -= 1900;

		#ifdef MAX6902_DEBUG
		printk("\n%s : Read RTC values\n",__FUNCTION__);
		printk("tm_hour: %i\n",dt->tm_hour);
		printk("tm_min : %i\n",dt->tm_min);
		printk("tm_sec : %i\n",dt->tm_sec);
		printk("tm_year: %i\n",dt->tm_year);
		printk("tm_mon : %i\n",dt->tm_mon);
		printk("tm_mday: %i\n",dt->tm_mday);
		printk("tm_wday: %i\n",dt->tm_wday);
		#endif

		return 0;
		}

		static int max6902_set_datetime(struct device dev, struct rtc_time dt)
		{
		dt->tm_year = dt->tm_year+1900;

		#ifdef MAX6902_DEBUG
		printk("\n%s : Setting RTC values\n",__FUNCTION__);
		printk("tm_sec : %i\n",dt->tm_sec);
		printk("tm_min : %i\n",dt->tm_min);
		printk("tm_hour: %i\n",dt->tm_hour);
		printk("tm_mday: %i\n",dt->tm_mday);
		printk("tm_wday: %i\n",dt->tm_wday);
		printk("tm_year: %i\n",dt->tm_year);
		#endif

		/* Remove write protection */
		max6902_set_reg(dev, 0xF, 0);

		max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec));
		max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min));
		max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour));

		max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday));
		max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1));
		max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday));
		max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100));
		max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100));

		/* Compulab used a delay here. However, the datasheet
		* does not mention a delay being required anywhere... */
		/* delay(2000); */

		/* Write protect */
		max6902_set_reg(dev, 0xF, 0x80);

		return 0;
		}

		static int max6902_read_time(struct device dev, struct rtc_time tm)
		{
		return max6902_get_datetime(dev, tm);
		}

		static int max6902_set_time(struct device dev, struct rtc_time tm)
		{
		return max6902_set_datetime(dev, tm);
		}

		static struct rtc_class_ops max6902_rtc_ops = {
		.read_time = max6902_read_time,
		.set_time = max6902_set_time,
		};

		static int __devinit max6902_probe(struct spi_device *spi)
		{
		struct rtc_device *rtc;
		unsigned char tmp;
		struct max6902 *chip;
		int res;

		rtc = rtc_device_register("max6902",
		&spi->dev, &max6902_rtc_ops, THIS_MODULE);
		if (IS_ERR(rtc))
		return PTR_ERR(rtc);

		spi->mode = SPI_MODE_3;
		spi->bits_per_word = 8;
		spi_setup(spi);

		chip = kzalloc(sizeof *chip, GFP_KERNEL);
		if (!chip) {
		rtc_device_unregister(rtc);
		return -ENOMEM;
		}
		chip->rtc = rtc;
		dev_set_drvdata(&spi->dev, chip);

		res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
		if (res) {
		rtc_device_unregister(rtc);
		return res;
		}

		return 0;
		}

		static int __devexit max6902_remove(struct spi_device *spi)
		{
		struct max6902 *chip = platform_get_drvdata(spi);
		struct rtc_device *rtc = chip->rtc;

		if (rtc)
		rtc_device_unregister(rtc);

		kfree(chip);

		return 0;
		}

		static struct spi_driver max6902_driver = {
		.driver = {
		.name = "max6902",
		.bus = &spi_bus_type,
		.owner = THIS_MODULE,
		},
		.probe = max6902_probe,
		.remove = __devexit_p(max6902_remove),
		};

		static __init int max6902_init(void)
		{
		printk("max6902 spi driver\n");
		return spi_register_driver(&max6902_driver);
		}
		module_init(max6902_init);

		static __exit void max6902_exit(void)
		{
		spi_unregister_driver(&max6902_driver);
		}
		module_exit(max6902_exit);

		MODULE_DESCRIPTION ("max6902 spi RTC driver");
		MODULE_AUTHOR ("Raphael Assenat");
		MODULE_LICENSE ("GPL");

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