drivers/misc/eeprom/eeprom_93cx6.c - third_party/linux - Git at Google

 /*
  * Copyright (C) 2004 - 2006 rt2x00 SourceForge Project
  * <http://rt2x00.serialmonkey.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  *
  * Module: eeprom_93cx6
  * Abstract: EEPROM reader routines for 93cx6 chipsets.
  * Supported chipsets: 93c46 & 93c66.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/eeprom_93cx6.h>

 MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
 MODULE_VERSION("1.0");
 MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
 MODULE_LICENSE("GPL");

 static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
 {
 	eeprom->reg_data_clock = 1;
 	eeprom->register_write(eeprom);

 	/*
 	 * Add a short delay for the pulse to work.
 	 * According to the specifications the "maximum minimum"
 	 * time should be 450ns.
 	 */
 	ndelay(450);
 }

 static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
 {
 	eeprom->reg_data_clock = 0;
 	eeprom->register_write(eeprom);

 	/*
 	 * Add a short delay for the pulse to work.
 	 * According to the specifications the "maximum minimum"
 	 * time should be 450ns.
 	 */
 	ndelay(450);
 }

 static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
 {
 	/*
 	 * Clear all flags, and enable chip select.
 	 */
 	eeprom->register_read(eeprom);
 	eeprom->reg_data_in = 0;
 	eeprom->reg_data_out = 0;
 	eeprom->reg_data_clock = 0;
 	eeprom->reg_chip_select = 1;
 	eeprom->drive_data = 1;
 	eeprom->register_write(eeprom);

 	/*
 	 * kick a pulse.
 	 */
 	eeprom_93cx6_pulse_high(eeprom);
 	eeprom_93cx6_pulse_low(eeprom);
 }

 static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
 {
 	/*
 	 * Clear chip_select and data_in flags.
 	 */
 	eeprom->register_read(eeprom);
 	eeprom->reg_data_in = 0;
 	eeprom->reg_chip_select = 0;
 	eeprom->register_write(eeprom);

 	/*
 	 * kick a pulse.
 	 */
 	eeprom_93cx6_pulse_high(eeprom);
 	eeprom_93cx6_pulse_low(eeprom);
 }

 static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
 	const u16 data, const u16 count)
 {
 	unsigned int i;

 	eeprom->register_read(eeprom);

 	/*
 	 * Clear data flags.
 	 */
 	eeprom->reg_data_in = 0;
 	eeprom->reg_data_out = 0;
 	eeprom->drive_data = 1;

 	/*
 	 * Start writing all bits.
 	 */
 	for (i = count; i > 0; i--) {
 		/*
 		 * Check if this bit needs to be set.
 		 */
 		eeprom->reg_data_in = !!(data & (1 << (i - 1)));

 		/*
 		 * Write the bit to the eeprom register.
 		 */
 		eeprom->register_write(eeprom);

 		/*
 		 * Kick a pulse.
 		 */
 		eeprom_93cx6_pulse_high(eeprom);
 		eeprom_93cx6_pulse_low(eeprom);
 	}

 	eeprom->reg_data_in = 0;
 	eeprom->register_write(eeprom);
 }

 static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
 	u16 *data, const u16 count)
 {
 	unsigned int i;
 	u16 buf = 0;

 	eeprom->register_read(eeprom);

 	/*
 	 * Clear data flags.
 	 */
 	eeprom->reg_data_in = 0;
 	eeprom->reg_data_out = 0;
 	eeprom->drive_data = 0;

 	/*
 	 * Start reading all bits.
 	 */
 	for (i = count; i > 0; i--) {
 		eeprom_93cx6_pulse_high(eeprom);

 		eeprom->register_read(eeprom);

 		/*
 		 * Clear data_in flag.
 		 */
 		eeprom->reg_data_in = 0;

 		/*
 		 * Read if the bit has been set.
 		 */
 		if (eeprom->reg_data_out)
 			buf |= (1 << (i - 1));

 		eeprom_93cx6_pulse_low(eeprom);
 	}

 	*data = buf;
 }

 /**
  * eeprom_93cx6_read - Read multiple words from eeprom
  * @eeprom: Pointer to eeprom structure
  * @word: Word index from where we should start reading
  * @data: target pointer where the information will have to be stored
  *
  * This function will read the eeprom data as host-endian word
  * into the given data pointer.
  */
 void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
 	u16 *data)
 {
 	u16 command;

 	/*
 	 * Initialize the eeprom register
 	 */
 	eeprom_93cx6_startup(eeprom);

 	/*
 	 * Select the read opcode and the word to be read.
 	 */
 	command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;
 	eeprom_93cx6_write_bits(eeprom, command,
 		PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

 	/*
 	 * Read the requested 16 bits.
 	 */
 	eeprom_93cx6_read_bits(eeprom, data, 16);

 	/*
 	 * Cleanup eeprom register.
 	 */
 	eeprom_93cx6_cleanup(eeprom);
 }
 EXPORT_SYMBOL_GPL(eeprom_93cx6_read);

 /**
  * eeprom_93cx6_multiread - Read multiple words from eeprom
  * @eeprom: Pointer to eeprom structure
  * @word: Word index from where we should start reading
  * @data: target pointer where the information will have to be stored
  * @words: Number of words that should be read.
  *
  * This function will read all requested words from the eeprom,
  * this is done by calling eeprom_93cx6_read() multiple times.
  * But with the additional change that while the eeprom_93cx6_read
  * will return host ordered bytes, this method will return little
  * endian words.
  */
 void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
 	__le16 *data, const u16 words)
 {
 	unsigned int i;
 	u16 tmp;

 	for (i = 0; i < words; i++) {
 		tmp = 0;
 		eeprom_93cx6_read(eeprom, word + i, &tmp);
 		data[i] = cpu_to_le16(tmp);
 	}
 }
 EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);

 /**
  * eeprom_93cx6_wren - set the write enable state
  * @eeprom: Pointer to eeprom structure
  * @enable: true to enable writes, otherwise disable writes
  *
  * Set the EEPROM write enable state to either allow or deny
  * writes depending on the @enable value.
  */
 void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)
 {
 	u16 command;

 	/* start the command */
 	eeprom_93cx6_startup(eeprom);

 	/* create command to enable/disable */

 	command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;
 	command <<= (eeprom->width - 2);

 	eeprom_93cx6_write_bits(eeprom, command,
 				PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

 	eeprom_93cx6_cleanup(eeprom);
 }
 EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);

 /**
  * eeprom_93cx6_write - write data to the EEPROM
  * @eeprom: Pointer to eeprom structure
  * @addr: Address to write data to.
  * @data: The data to write to address @addr.
  *
  * Write the @data to the specified @addr in the EEPROM and
  * waiting for the device to finish writing.
  *
  * Note, since we do not expect large number of write operations
  * we delay in between parts of the operation to avoid using excessive
  * amounts of CPU time busy waiting.
  */
 void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)
 {
 	int timeout = 100;
 	u16 command;

 	/* start the command */
 	eeprom_93cx6_startup(eeprom);

 	command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;
 	command |= addr;

 	/* send write command */
 	eeprom_93cx6_write_bits(eeprom, command,
 				PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

 	/* send data */
 	eeprom_93cx6_write_bits(eeprom, data, 16);

 	/* get ready to check for busy */
 	eeprom->drive_data = 0;
 	eeprom->reg_chip_select = 1;
 	eeprom->register_write(eeprom);

 	/* wait at-least 250ns to get DO to be the busy signal */
 	usleep_range(1000, 2000);

 	/* wait for DO to go high to signify finish */

 	while (true) {
 		eeprom->register_read(eeprom);

 		if (eeprom->reg_data_out)
 			break;

 		usleep_range(1000, 2000);

 		if (--timeout <= 0) {
 			printk(KERN_ERR "%s: timeout\n", __func__);
 			break;
 		}
 	}

 	eeprom_93cx6_cleanup(eeprom);
 }
 EXPORT_SYMBOL_GPL(eeprom_93cx6_write);
	/*
	* Copyright (C) 2004 - 2006 rt2x00 SourceForge Project
	* <http://rt2x00.serialmonkey.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* Module: eeprom_93cx6
	* Abstract: EEPROM reader routines for 93cx6 chipsets.
	* Supported chipsets: 93c46 & 93c66.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/delay.h>
	#include <linux/eeprom_93cx6.h>

	MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
	MODULE_VERSION("1.0");
	MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
	MODULE_LICENSE("GPL");

	static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
	{
	eeprom->reg_data_clock = 1;
	eeprom->register_write(eeprom);

	/*
	* Add a short delay for the pulse to work.
	* According to the specifications the "maximum minimum"
	* time should be 450ns.
	*/
	ndelay(450);
	}

	static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
	{
	eeprom->reg_data_clock = 0;
	eeprom->register_write(eeprom);

	/*
	* Add a short delay for the pulse to work.
	* According to the specifications the "maximum minimum"
	* time should be 450ns.
	*/
	ndelay(450);
	}

	static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
	{
	/*
	* Clear all flags, and enable chip select.
	*/
	eeprom->register_read(eeprom);
	eeprom->reg_data_in = 0;
	eeprom->reg_data_out = 0;
	eeprom->reg_data_clock = 0;
	eeprom->reg_chip_select = 1;
	eeprom->drive_data = 1;
	eeprom->register_write(eeprom);

	/*
	* kick a pulse.
	*/
	eeprom_93cx6_pulse_high(eeprom);
	eeprom_93cx6_pulse_low(eeprom);
	}

	static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
	{
	/*
	* Clear chip_select and data_in flags.
	*/
	eeprom->register_read(eeprom);
	eeprom->reg_data_in = 0;
	eeprom->reg_chip_select = 0;
	eeprom->register_write(eeprom);

	/*
	* kick a pulse.
	*/
	eeprom_93cx6_pulse_high(eeprom);
	eeprom_93cx6_pulse_low(eeprom);
	}

	static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
	const u16 data, const u16 count)
	{
	unsigned int i;

	eeprom->register_read(eeprom);

	/*
	* Clear data flags.
	*/
	eeprom->reg_data_in = 0;
	eeprom->reg_data_out = 0;
	eeprom->drive_data = 1;

	/*
	* Start writing all bits.
	*/
	for (i = count; i > 0; i--) {
	/*
	* Check if this bit needs to be set.
	*/
	eeprom->reg_data_in = !!(data & (1 << (i - 1)));

	/*
	* Write the bit to the eeprom register.
	*/
	eeprom->register_write(eeprom);

	/*
	* Kick a pulse.
	*/
	eeprom_93cx6_pulse_high(eeprom);
	eeprom_93cx6_pulse_low(eeprom);
	}

	eeprom->reg_data_in = 0;
	eeprom->register_write(eeprom);
	}

	static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
	u16 *data, const u16 count)
	{
	unsigned int i;
	u16 buf = 0;

	eeprom->register_read(eeprom);

	/*
	* Clear data flags.
	*/
	eeprom->reg_data_in = 0;
	eeprom->reg_data_out = 0;
	eeprom->drive_data = 0;

	/*
	* Start reading all bits.
	*/
	for (i = count; i > 0; i--) {
	eeprom_93cx6_pulse_high(eeprom);

	eeprom->register_read(eeprom);

	/*
	* Clear data_in flag.
	*/
	eeprom->reg_data_in = 0;

	/*
	* Read if the bit has been set.
	*/
	if (eeprom->reg_data_out)
	buf \|= (1 << (i - 1));

	eeprom_93cx6_pulse_low(eeprom);
	}

	*data = buf;
	}

	/**
	* eeprom_93cx6_read - Read multiple words from eeprom
	* @eeprom: Pointer to eeprom structure
	* @word: Word index from where we should start reading
	* @data: target pointer where the information will have to be stored
	*
	* This function will read the eeprom data as host-endian word
	* into the given data pointer.
	*/
	void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
	u16 *data)
	{
	u16 command;

	/*
	* Initialize the eeprom register
	*/
	eeprom_93cx6_startup(eeprom);

	/*
	* Select the read opcode and the word to be read.
	*/
	command = (PCI_EEPROM_READ_OPCODE << eeprom->width) \| word;
	eeprom_93cx6_write_bits(eeprom, command,
	PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

	/*
	* Read the requested 16 bits.
	*/
	eeprom_93cx6_read_bits(eeprom, data, 16);

	/*
	* Cleanup eeprom register.
	*/
	eeprom_93cx6_cleanup(eeprom);
	}
	EXPORT_SYMBOL_GPL(eeprom_93cx6_read);

	/**
	* eeprom_93cx6_multiread - Read multiple words from eeprom
	* @eeprom: Pointer to eeprom structure
	* @word: Word index from where we should start reading
	* @data: target pointer where the information will have to be stored
	* @words: Number of words that should be read.
	*
	* This function will read all requested words from the eeprom,
	* this is done by calling eeprom_93cx6_read() multiple times.
	* But with the additional change that while the eeprom_93cx6_read
	* will return host ordered bytes, this method will return little
	* endian words.
	*/
	void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
	__le16 *data, const u16 words)
	{
	unsigned int i;
	u16 tmp;

	for (i = 0; i < words; i++) {
	tmp = 0;
	eeprom_93cx6_read(eeprom, word + i, &tmp);
	data[i] = cpu_to_le16(tmp);
	}
	}
	EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);

	/**
	* eeprom_93cx6_wren - set the write enable state
	* @eeprom: Pointer to eeprom structure
	* @enable: true to enable writes, otherwise disable writes
	*
	* Set the EEPROM write enable state to either allow or deny
	* writes depending on the @enable value.
	*/
	void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)
	{
	u16 command;

	/* start the command */
	eeprom_93cx6_startup(eeprom);

	/* create command to enable/disable */

	command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;
	command <<= (eeprom->width - 2);

	eeprom_93cx6_write_bits(eeprom, command,
	PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

	eeprom_93cx6_cleanup(eeprom);
	}
	EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);

	/**
	* eeprom_93cx6_write - write data to the EEPROM
	* @eeprom: Pointer to eeprom structure
	* @addr: Address to write data to.
	* @data: The data to write to address @addr.
	*
	* Write the @data to the specified @addr in the EEPROM and
	* waiting for the device to finish writing.
	*
	* Note, since we do not expect large number of write operations
	* we delay in between parts of the operation to avoid using excessive
	* amounts of CPU time busy waiting.
	*/
	void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)
	{
	int timeout = 100;
	u16 command;

	/* start the command */
	eeprom_93cx6_startup(eeprom);

	command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;
	command \|= addr;

	/* send write command */
	eeprom_93cx6_write_bits(eeprom, command,
	PCI_EEPROM_WIDTH_OPCODE + eeprom->width);

	/* send data */
	eeprom_93cx6_write_bits(eeprom, data, 16);

	/* get ready to check for busy */
	eeprom->drive_data = 0;
	eeprom->reg_chip_select = 1;
	eeprom->register_write(eeprom);

	/* wait at-least 250ns to get DO to be the busy signal */
	usleep_range(1000, 2000);

	/* wait for DO to go high to signify finish */

	while (true) {
	eeprom->register_read(eeprom);

	if (eeprom->reg_data_out)
	break;

	usleep_range(1000, 2000);

	if (--timeout <= 0) {
	printk(KERN_ERR "%s: timeout\n", __func__);
	break;
	}
	}

	eeprom_93cx6_cleanup(eeprom);
	}
	EXPORT_SYMBOL_GPL(eeprom_93cx6_write);