drivers/misc/ds4510.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright 2008 Extreme Engineering Solutions, Inc.
  */

 /*
  * Driver for DS4510, a CPU supervisor with integrated EEPROM, SRAM,
  * and 4 programmable non-volatile GPIO pins.
  */

 #include <common.h>
 #include <i2c.h>
 #include <command.h>
 #include <linux/delay.h>
 #include "ds4510.h"

 enum {
 	DS4510_CMD_INFO,
 	DS4510_CMD_DEVICE,
 	DS4510_CMD_NV,
 	DS4510_CMD_RSTDELAY,
 	DS4510_CMD_OUTPUT,
 	DS4510_CMD_INPUT,
 	DS4510_CMD_PULLUP,
 	DS4510_CMD_EEPROM,
 	DS4510_CMD_SEEPROM,
 	DS4510_CMD_SRAM,
 };

 /*
  * Write to DS4510, taking page boundaries into account
  */
 static int ds4510_mem_write(uint8_t chip, int offset, uint8_t *buf, int count)
 {
 	int wrlen;
 	int i = 0;

 	do {
 		wrlen = DS4510_EEPROM_PAGE_SIZE -
 			DS4510_EEPROM_PAGE_OFFSET(offset);
 		if (count < wrlen)
 			wrlen = count;
 		if (i2c_write(chip, offset, 1, &buf[i], wrlen))
 			return -1;

 		/*
 		 * This delay isn't needed for SRAM writes but shouldn't delay
 		 * things too much, so do it unconditionally for simplicity
 		 */
 		udelay(DS4510_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
 		count -= wrlen;
 		offset += wrlen;
 		i += wrlen;
 	} while (count > 0);

 	return 0;
 }

 /*
  * General read from DS4510
  */
 static int ds4510_mem_read(uint8_t chip, int offset, uint8_t *buf, int count)
 {
 	return i2c_read(chip, offset, 1, buf, count);
 }

 /*
  * Write SEE bit in config register.
  * nv = 0 - Writes to SEEPROM registers behave like EEPROM
  * nv = 1 - Writes to SEEPROM registers behave like SRAM
  */
 static int ds4510_see_write(uint8_t chip, uint8_t nv)
 {
 	uint8_t data;

 	if (i2c_read(chip, DS4510_CFG, 1, &data, 1))
 		return -1;

 	if (nv)	/* Treat SEEPROM bits as EEPROM */
 		data &= ~DS4510_CFG_SEE;
 	else	/* Treat SEEPROM bits as SRAM */
 		data |= DS4510_CFG_SEE;

 	return ds4510_mem_write(chip, DS4510_CFG, &data, 1);
 }

 /*
  * Write de-assertion of reset signal delay
  */
 static int ds4510_rstdelay_write(uint8_t chip, uint8_t delay)
 {
 	uint8_t data;

 	if (i2c_read(chip, DS4510_RSTDELAY, 1, &data, 1))
 		return -1;

 	data &= ~DS4510_RSTDELAY_MASK;
 	data |= delay & DS4510_RSTDELAY_MASK;

 	return ds4510_mem_write(chip, DS4510_RSTDELAY, &data, 1);
 }

 /*
  * Write pullup characteristics of IO pins
  */
 static int ds4510_pullup_write(uint8_t chip, uint8_t val)
 {
 	val &= DS4510_IO_MASK;

 	return ds4510_mem_write(chip, DS4510_PULLUP, (uint8_t *)&val, 1);
 }

 /*
  * Read pullup characteristics of IO pins
  */
 static int ds4510_pullup_read(uint8_t chip)
 {
 	uint8_t val;

 	if (i2c_read(chip, DS4510_PULLUP, 1, &val, 1))
 		return -1;

 	return val & DS4510_IO_MASK;
 }

 /*
  * Write drive level of IO pins
  */
 static int ds4510_gpio_write(uint8_t chip, uint8_t val)
 {
 	uint8_t data;
 	int i;

 	for (i = 0; i < DS4510_NUM_IO; i++) {
 		if (i2c_read(chip, DS4510_IO0 - i, 1, &data, 1))
 			return -1;

 		if (val & (0x1 << i))
 			data |= 0x1;
 		else
 			data &= ~0x1;

 		if (ds4510_mem_write(chip, DS4510_IO0 - i, &data, 1))
 			return -1;
 	}

 	return 0;
 }

 /*
  * Read drive level of IO pins
  */
 static int ds4510_gpio_read(uint8_t chip)
 {
 	uint8_t data;
 	int val = 0;
 	int i;

 	for (i = 0; i < DS4510_NUM_IO; i++) {
 		if (i2c_read(chip, DS4510_IO0 - i, 1, &data, 1))
 			return -1;

 		if (data & 1)
 			val |= (1 << i);
 	}

 	return val;
 }

 /*
  * Read physical level of IO pins
  */
 static int ds4510_gpio_read_val(uint8_t chip)
 {
 	uint8_t val;

 	if (i2c_read(chip, DS4510_IO_STATUS, 1, &val, 1))
 		return -1;

 	return val & DS4510_IO_MASK;
 }

 /*
  * Display DS4510 information
  */
 static int ds4510_info(uint8_t chip)
 {
 	int i;
 	int tmp;
 	uint8_t data;

 	printf("DS4510 @ 0x%x:\n\n", chip);

 	if (i2c_read(chip, DS4510_RSTDELAY, 1, &data, 1))
 		return -1;
 	printf("rstdelay = 0x%x\n\n", data & DS4510_RSTDELAY_MASK);

 	if (i2c_read(chip, DS4510_CFG, 1, &data, 1))
 		return -1;
 	printf("config   = 0x%x\n", data);
 	printf(" /ready  = %d\n", data & DS4510_CFG_READY ? 1 : 0);
 	printf(" trip pt = %d\n", data & DS4510_CFG_TRIP_POINT ? 1 : 0);
 	printf(" rst sts = %d\n", data & DS4510_CFG_RESET ? 1 : 0);
 	printf(" /see    = %d\n", data & DS4510_CFG_SEE ? 1 : 0);
 	printf(" swrst   = %d\n\n", data & DS4510_CFG_SWRST ? 1 : 0);

 	printf("gpio pins: 3210\n");
 	printf("---------------\n");
 	printf("pullup     ");

 	tmp = ds4510_pullup_read(chip);
 	if (tmp == -1)
 		return tmp;
 	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
 		printf("%d", (tmp & (1 << i)) ? 1 : 0);
 	printf("\n");

 	printf("driven     ");
 	tmp = ds4510_gpio_read(chip);
 	if (tmp == -1)
 		return -1;
 	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
 		printf("%d", (tmp & (1 << i)) ? 1 : 0);
 	printf("\n");

 	printf("read       ");
 	tmp = ds4510_gpio_read_val(chip);
 	if (tmp == -1)
 		return -1;
 	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
 		printf("%d", (tmp & (1 << i)) ? 1 : 0);
 	printf("\n");

 	return 0;
 }

 struct cmd_tbl cmd_ds4510[] = {
 	U_BOOT_CMD_MKENT(device, 3, 0, (void *)DS4510_CMD_DEVICE, "", ""),
 	U_BOOT_CMD_MKENT(nv, 3, 0, (void *)DS4510_CMD_NV, "", ""),
 	U_BOOT_CMD_MKENT(output, 4, 0, (void *)DS4510_CMD_OUTPUT, "", ""),
 	U_BOOT_CMD_MKENT(input, 3, 0, (void *)DS4510_CMD_INPUT, "", ""),
 	U_BOOT_CMD_MKENT(pullup, 4, 0, (void *)DS4510_CMD_PULLUP, "", ""),
 	U_BOOT_CMD_MKENT(info, 2, 0, (void *)DS4510_CMD_INFO, "", ""),
 	U_BOOT_CMD_MKENT(rstdelay, 3, 0, (void *)DS4510_CMD_RSTDELAY, "", ""),
 	U_BOOT_CMD_MKENT(eeprom, 6, 0, (void *)DS4510_CMD_EEPROM, "", ""),
 	U_BOOT_CMD_MKENT(seeprom, 6, 0, (void *)DS4510_CMD_SEEPROM, "", ""),
 	U_BOOT_CMD_MKENT(sram, 6, 0, (void *)DS4510_CMD_SRAM, "", ""),
 };

 int do_ds4510(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
 	static uint8_t chip = 0x51;
 	struct cmd_tbl *c;
 	ulong ul_arg2 = 0;
 	ulong ul_arg3 = 0;
 	int tmp;
 	ulong addr;
 	ulong off;
 	ulong cnt;
 	int end;
 	int (*rw_func)(uint8_t, int, uint8_t *, int);

 	c = find_cmd_tbl(argv[1], cmd_ds4510, ARRAY_SIZE(cmd_ds4510));

 	/* All commands but "device" require 'maxargs' arguments */
 	if (!c || !((argc == (c->maxargs)) ||
 		(((int)c->cmd == DS4510_CMD_DEVICE) &&
 		 (argc == (c->maxargs - 1))))) {
 		return cmd_usage(cmdtp);
 	}

 	/* arg2 used as chip addr and pin number */
 	if (argc > 2)
 		ul_arg2 = simple_strtoul(argv[2], NULL, 16);

 	/* arg3 used as output/pullup value */
 	if (argc > 3)
 		ul_arg3 = simple_strtoul(argv[3], NULL, 16);

 	switch ((int)c->cmd) {
 	case DS4510_CMD_DEVICE:
 		if (argc == 3)
 			chip = ul_arg2;
 		printf("Current device address: 0x%x\n", chip);
 		return 0;
 	case DS4510_CMD_NV:
 		return ds4510_see_write(chip, ul_arg2);
 	case DS4510_CMD_OUTPUT:
 		tmp = ds4510_gpio_read(chip);
 		if (tmp == -1)
 			return -1;
 		if (ul_arg3)
 			tmp |= (1 << ul_arg2);
 		else
 			tmp &= ~(1 << ul_arg2);
 		return ds4510_gpio_write(chip, tmp);
 	case DS4510_CMD_INPUT:
 		tmp = ds4510_gpio_read_val(chip);
 		if (tmp == -1)
 			return -1;
 		return (tmp & (1 << ul_arg2)) != 0;
 	case DS4510_CMD_PULLUP:
 		tmp = ds4510_pullup_read(chip);
 		if (tmp == -1)
 			return -1;
 		if (ul_arg3)
 			tmp |= (1 << ul_arg2);
 		else
 			tmp &= ~(1 << ul_arg2);
 		return ds4510_pullup_write(chip, tmp);
 	case DS4510_CMD_INFO:
 		return ds4510_info(chip);
 	case DS4510_CMD_RSTDELAY:
 		return ds4510_rstdelay_write(chip, ul_arg2);
 	case DS4510_CMD_EEPROM:
 		end = DS4510_EEPROM + DS4510_EEPROM_SIZE;
 		off = DS4510_EEPROM;
 		break;
 	case DS4510_CMD_SEEPROM:
 		end = DS4510_SEEPROM + DS4510_SEEPROM_SIZE;
 		off = DS4510_SEEPROM;
 		break;
 	case DS4510_CMD_SRAM:
 		end = DS4510_SRAM + DS4510_SRAM_SIZE;
 		off = DS4510_SRAM;
 		break;
 	default:
 		/* We should never get here... */
 		return 1;
 	}

 	/* Only eeprom, seeprom, and sram commands should make it here */
 	if (strcmp(argv[2], "read") == 0)
 		rw_func = ds4510_mem_read;
 	else if (strcmp(argv[2], "write") == 0)
 		rw_func = ds4510_mem_write;
 	else
 		return cmd_usage(cmdtp);

 	addr = simple_strtoul(argv[3], NULL, 16);
 	off += simple_strtoul(argv[4], NULL, 16);
 	cnt = simple_strtoul(argv[5], NULL, 16);

 	if ((off + cnt) > end) {
 		printf("ERROR: invalid len\n");
 		return -1;
 	}

 	return rw_func(chip, off, (uint8_t *)addr, cnt);
 }

 U_BOOT_CMD(
 	ds4510,	6,	1,	do_ds4510,
 	"ds4510 eeprom/seeprom/sram/gpio access",
 	"device [dev]\n"
 	"	- show or set current device address\n"
 	"ds4510 info\n"
 	"	- display ds4510 info\n"
 	"ds4510 output pin 0|1\n"
 	"	- set pin low or high-Z\n"
 	"ds4510 input pin\n"
 	"	- read value of pin\n"
 	"ds4510 pullup pin 0|1\n"
 	"	- disable/enable pullup on specified pin\n"
 	"ds4510 nv 0|1\n"
 	"	- make gpio and seeprom writes volatile/non-volatile"
 	"\n"
 	"ds4510 rstdelay 0-3\n"
 	"	- set reset output delay"
 	"\n"
 	"ds4510 eeprom read addr off cnt\n"
 	"ds4510 eeprom write addr off cnt\n"
 	"	- read/write 'cnt' bytes at EEPROM offset 'off'\n"
 	"ds4510 seeprom read addr off cnt\n"
 	"ds4510 seeprom write addr off cnt\n"
 	"	- read/write 'cnt' bytes at SRAM-shadowed EEPROM offset 'off'\n"
 	"ds4510 sram read addr off cnt\n"
 	"ds4510 sram write addr off cnt\n"
 	"	- read/write 'cnt' bytes at SRAM offset 'off'"
 );
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright 2008 Extreme Engineering Solutions, Inc.
	*/

	/*
	* Driver for DS4510, a CPU supervisor with integrated EEPROM, SRAM,
	* and 4 programmable non-volatile GPIO pins.
	*/

	#include <common.h>
	#include <i2c.h>
	#include <command.h>
	#include <linux/delay.h>
	#include "ds4510.h"

	enum {
	DS4510_CMD_INFO,
	DS4510_CMD_DEVICE,
	DS4510_CMD_NV,
	DS4510_CMD_RSTDELAY,
	DS4510_CMD_OUTPUT,
	DS4510_CMD_INPUT,
	DS4510_CMD_PULLUP,
	DS4510_CMD_EEPROM,
	DS4510_CMD_SEEPROM,
	DS4510_CMD_SRAM,
	};

	/*
	* Write to DS4510, taking page boundaries into account
	*/
	static int ds4510_mem_write(uint8_t chip, int offset, uint8_t *buf, int count)
	{
	int wrlen;
	int i = 0;

	do {
	wrlen = DS4510_EEPROM_PAGE_SIZE -
	DS4510_EEPROM_PAGE_OFFSET(offset);
	if (count < wrlen)
	wrlen = count;
	if (i2c_write(chip, offset, 1, &buf[i], wrlen))
	return -1;

	/*
	* This delay isn't needed for SRAM writes but shouldn't delay
	* things too much, so do it unconditionally for simplicity
	*/
	udelay(DS4510_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
	count -= wrlen;
	offset += wrlen;
	i += wrlen;
	} while (count > 0);

	return 0;
	}

	/*
	* General read from DS4510
	*/
	static int ds4510_mem_read(uint8_t chip, int offset, uint8_t *buf, int count)
	{
	return i2c_read(chip, offset, 1, buf, count);
	}

	/*
	* Write SEE bit in config register.
	* nv = 0 - Writes to SEEPROM registers behave like EEPROM
	* nv = 1 - Writes to SEEPROM registers behave like SRAM
	*/
	static int ds4510_see_write(uint8_t chip, uint8_t nv)
	{
	uint8_t data;

	if (i2c_read(chip, DS4510_CFG, 1, &data, 1))
	return -1;

	if (nv) /* Treat SEEPROM bits as EEPROM */
	data &= ~DS4510_CFG_SEE;
	else /* Treat SEEPROM bits as SRAM */
	data \|= DS4510_CFG_SEE;

	return ds4510_mem_write(chip, DS4510_CFG, &data, 1);
	}

	/*
	* Write de-assertion of reset signal delay
	*/
	static int ds4510_rstdelay_write(uint8_t chip, uint8_t delay)
	{
	uint8_t data;

	if (i2c_read(chip, DS4510_RSTDELAY, 1, &data, 1))
	return -1;

	data &= ~DS4510_RSTDELAY_MASK;
	data \|= delay & DS4510_RSTDELAY_MASK;

	return ds4510_mem_write(chip, DS4510_RSTDELAY, &data, 1);
	}

	/*
	* Write pullup characteristics of IO pins
	*/
	static int ds4510_pullup_write(uint8_t chip, uint8_t val)
	{
	val &= DS4510_IO_MASK;

	return ds4510_mem_write(chip, DS4510_PULLUP, (uint8_t *)&val, 1);
	}

	/*
	* Read pullup characteristics of IO pins
	*/
	static int ds4510_pullup_read(uint8_t chip)
	{
	uint8_t val;

	if (i2c_read(chip, DS4510_PULLUP, 1, &val, 1))
	return -1;

	return val & DS4510_IO_MASK;
	}

	/*
	* Write drive level of IO pins
	*/
	static int ds4510_gpio_write(uint8_t chip, uint8_t val)
	{
	uint8_t data;
	int i;

	for (i = 0; i < DS4510_NUM_IO; i++) {
	if (i2c_read(chip, DS4510_IO0 - i, 1, &data, 1))
	return -1;

	if (val & (0x1 << i))
	data \|= 0x1;
	else
	data &= ~0x1;

	if (ds4510_mem_write(chip, DS4510_IO0 - i, &data, 1))
	return -1;
	}

	return 0;
	}

	/*
	* Read drive level of IO pins
	*/
	static int ds4510_gpio_read(uint8_t chip)
	{
	uint8_t data;
	int val = 0;
	int i;

	for (i = 0; i < DS4510_NUM_IO; i++) {
	if (i2c_read(chip, DS4510_IO0 - i, 1, &data, 1))
	return -1;

	if (data & 1)
	val \|= (1 << i);
	}

	return val;
	}

	/*
	* Read physical level of IO pins
	*/
	static int ds4510_gpio_read_val(uint8_t chip)
	{
	uint8_t val;

	if (i2c_read(chip, DS4510_IO_STATUS, 1, &val, 1))
	return -1;

	return val & DS4510_IO_MASK;
	}

	/*
	* Display DS4510 information
	*/
	static int ds4510_info(uint8_t chip)
	{
	int i;
	int tmp;
	uint8_t data;

	printf("DS4510 @ 0x%x:\n\n", chip);

	if (i2c_read(chip, DS4510_RSTDELAY, 1, &data, 1))
	return -1;
	printf("rstdelay = 0x%x\n\n", data & DS4510_RSTDELAY_MASK);

	if (i2c_read(chip, DS4510_CFG, 1, &data, 1))
	return -1;
	printf("config = 0x%x\n", data);
	printf(" /ready = %d\n", data & DS4510_CFG_READY ? 1 : 0);
	printf(" trip pt = %d\n", data & DS4510_CFG_TRIP_POINT ? 1 : 0);
	printf(" rst sts = %d\n", data & DS4510_CFG_RESET ? 1 : 0);
	printf(" /see = %d\n", data & DS4510_CFG_SEE ? 1 : 0);
	printf(" swrst = %d\n\n", data & DS4510_CFG_SWRST ? 1 : 0);

	printf("gpio pins: 3210\n");
	printf("---------------\n");
	printf("pullup ");

	tmp = ds4510_pullup_read(chip);
	if (tmp == -1)
	return tmp;
	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
	printf("%d", (tmp & (1 << i)) ? 1 : 0);
	printf("\n");

	printf("driven ");
	tmp = ds4510_gpio_read(chip);
	if (tmp == -1)
	return -1;
	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
	printf("%d", (tmp & (1 << i)) ? 1 : 0);
	printf("\n");

	printf("read ");
	tmp = ds4510_gpio_read_val(chip);
	if (tmp == -1)
	return -1;
	for (i = DS4510_NUM_IO - 1; i >= 0; i--)
	printf("%d", (tmp & (1 << i)) ? 1 : 0);
	printf("\n");

	return 0;
	}

	struct cmd_tbl cmd_ds4510[] = {
	U_BOOT_CMD_MKENT(device, 3, 0, (void *)DS4510_CMD_DEVICE, "", ""),
	U_BOOT_CMD_MKENT(nv, 3, 0, (void *)DS4510_CMD_NV, "", ""),
	U_BOOT_CMD_MKENT(output, 4, 0, (void *)DS4510_CMD_OUTPUT, "", ""),
	U_BOOT_CMD_MKENT(input, 3, 0, (void *)DS4510_CMD_INPUT, "", ""),
	U_BOOT_CMD_MKENT(pullup, 4, 0, (void *)DS4510_CMD_PULLUP, "", ""),
	U_BOOT_CMD_MKENT(info, 2, 0, (void *)DS4510_CMD_INFO, "", ""),
	U_BOOT_CMD_MKENT(rstdelay, 3, 0, (void *)DS4510_CMD_RSTDELAY, "", ""),
	U_BOOT_CMD_MKENT(eeprom, 6, 0, (void *)DS4510_CMD_EEPROM, "", ""),
	U_BOOT_CMD_MKENT(seeprom, 6, 0, (void *)DS4510_CMD_SEEPROM, "", ""),
	U_BOOT_CMD_MKENT(sram, 6, 0, (void *)DS4510_CMD_SRAM, "", ""),
	};

	int do_ds4510(struct cmd_tbl cmdtp, int flag, int argc, char const argv[])
	{
	static uint8_t chip = 0x51;
	struct cmd_tbl *c;
	ulong ul_arg2 = 0;
	ulong ul_arg3 = 0;
	int tmp;
	ulong addr;
	ulong off;
	ulong cnt;
	int end;
	int (rw_func)(uint8_t, int, uint8_t , int);

	c = find_cmd_tbl(argv[1], cmd_ds4510, ARRAY_SIZE(cmd_ds4510));

	/* All commands but "device" require 'maxargs' arguments */
	if (!c \|\| !((argc == (c->maxargs)) \|\|
	(((int)c->cmd == DS4510_CMD_DEVICE) &&
	(argc == (c->maxargs - 1))))) {
	return cmd_usage(cmdtp);
	}

	/* arg2 used as chip addr and pin number */
	if (argc > 2)
	ul_arg2 = simple_strtoul(argv[2], NULL, 16);

	/* arg3 used as output/pullup value */
	if (argc > 3)
	ul_arg3 = simple_strtoul(argv[3], NULL, 16);

	switch ((int)c->cmd) {
	case DS4510_CMD_DEVICE:
	if (argc == 3)
	chip = ul_arg2;
	printf("Current device address: 0x%x\n", chip);
	return 0;
	case DS4510_CMD_NV:
	return ds4510_see_write(chip, ul_arg2);
	case DS4510_CMD_OUTPUT:
	tmp = ds4510_gpio_read(chip);
	if (tmp == -1)
	return -1;
	if (ul_arg3)
	tmp \|= (1 << ul_arg2);
	else
	tmp &= ~(1 << ul_arg2);
	return ds4510_gpio_write(chip, tmp);
	case DS4510_CMD_INPUT:
	tmp = ds4510_gpio_read_val(chip);
	if (tmp == -1)
	return -1;
	return (tmp & (1 << ul_arg2)) != 0;
	case DS4510_CMD_PULLUP:
	tmp = ds4510_pullup_read(chip);
	if (tmp == -1)
	return -1;
	if (ul_arg3)
	tmp \|= (1 << ul_arg2);
	else
	tmp &= ~(1 << ul_arg2);
	return ds4510_pullup_write(chip, tmp);
	case DS4510_CMD_INFO:
	return ds4510_info(chip);
	case DS4510_CMD_RSTDELAY:
	return ds4510_rstdelay_write(chip, ul_arg2);
	case DS4510_CMD_EEPROM:
	end = DS4510_EEPROM + DS4510_EEPROM_SIZE;
	off = DS4510_EEPROM;
	break;
	case DS4510_CMD_SEEPROM:
	end = DS4510_SEEPROM + DS4510_SEEPROM_SIZE;
	off = DS4510_SEEPROM;
	break;
	case DS4510_CMD_SRAM:
	end = DS4510_SRAM + DS4510_SRAM_SIZE;
	off = DS4510_SRAM;
	break;
	default:
	/* We should never get here... */
	return 1;
	}

	/* Only eeprom, seeprom, and sram commands should make it here */
	if (strcmp(argv[2], "read") == 0)
	rw_func = ds4510_mem_read;
	else if (strcmp(argv[2], "write") == 0)
	rw_func = ds4510_mem_write;
	else
	return cmd_usage(cmdtp);

	addr = simple_strtoul(argv[3], NULL, 16);
	off += simple_strtoul(argv[4], NULL, 16);
	cnt = simple_strtoul(argv[5], NULL, 16);

	if ((off + cnt) > end) {
	printf("ERROR: invalid len\n");
	return -1;
	}

	return rw_func(chip, off, (uint8_t *)addr, cnt);
	}

	U_BOOT_CMD(
	ds4510, 6, 1, do_ds4510,
	"ds4510 eeprom/seeprom/sram/gpio access",
	"device [dev]\n"
	" - show or set current device address\n"
	"ds4510 info\n"
	" - display ds4510 info\n"
	"ds4510 output pin 0\|1\n"
	" - set pin low or high-Z\n"
	"ds4510 input pin\n"
	" - read value of pin\n"
	"ds4510 pullup pin 0\|1\n"
	" - disable/enable pullup on specified pin\n"
	"ds4510 nv 0\|1\n"
	" - make gpio and seeprom writes volatile/non-volatile"
	"\n"
	"ds4510 rstdelay 0-3\n"
	" - set reset output delay"
	"\n"
	"ds4510 eeprom read addr off cnt\n"
	"ds4510 eeprom write addr off cnt\n"
	" - read/write 'cnt' bytes at EEPROM offset 'off'\n"
	"ds4510 seeprom read addr off cnt\n"
	"ds4510 seeprom write addr off cnt\n"
	" - read/write 'cnt' bytes at SRAM-shadowed EEPROM offset 'off'\n"
	"ds4510 sram read addr off cnt\n"
	"ds4510 sram write addr off cnt\n"
	" - read/write 'cnt' bytes at SRAM offset 'off'"
	);