drivers/rtc/rtc-max6902.c - kernel/msm - Gitiles

 /* 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 const 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");
	/* 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 const 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");