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Commit 14dd1ff0 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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memory_accessor: implement the new memory_accessor interfaces for SPI EEPROMs 



- Define new setup() hook to export the accessor
 - Implement accessor methods

Moves some error checking out of the sysfs interface code into the layer
below it, which is now shared by both sysfs and memory access code.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7274ec8b

drivers/misc/eeprom/at25.c

+44 −14
Original line number Original line Diff line number Diff line
@@ -30,6 +30,7 @@ 




struct at25_data {

struct at25_data {

	struct spi_device	*spi;

	struct spi_device	*spi;

	struct memory_accessor	mem;

	struct mutex		lock;

	struct mutex		lock;

	struct spi_eeprom	chip;

	struct spi_eeprom	chip;

	struct bin_attribute	bin;

	struct bin_attribute	bin;
@@ -75,6 +76,13 @@ at25_ee_read( 
	struct spi_transfer	t[2];

	struct spi_transfer	t[2];

	struct spi_message	m;

	struct spi_message	m;





	if (unlikely(offset >= at25->bin.size))

		return 0;

	if ((offset + count) > at25->bin.size)

		count = at25->bin.size - offset;

	if (unlikely(!count))

		return count;



	cp = command;

	cp = command;

	*cp++ = AT25_READ;

	*cp++ = AT25_READ;
@@ -127,13 +135,6 @@ at25_bin_read(struct kobject *kobj, struct bin_attribute *bin_attr, 
	dev = container_of(kobj, struct device, kobj);

	dev = container_of(kobj, struct device, kobj);

	at25 = dev_get_drvdata(dev);

	at25 = dev_get_drvdata(dev);





	if (unlikely(off >= at25->bin.size))

		return 0;

	if ((off + count) > at25->bin.size)

		count = at25->bin.size - off;

	if (unlikely(!count))

		return count;



	return at25_ee_read(at25, buf, off, count);

	return at25_ee_read(at25, buf, off, count);

}

}
@@ -146,6 +147,13 @@ at25_ee_write(struct at25_data *at25, char *buf, loff_t off, size_t count) 
	unsigned		buf_size;

	unsigned		buf_size;

	u8			*bounce;

	u8			*bounce;





	if (unlikely(off >= at25->bin.size))

		return -EFBIG;

	if ((off + count) > at25->bin.size)

		count = at25->bin.size - off;

	if (unlikely(!count))

		return count;



	/* Temp buffer starts with command and address */

	/* Temp buffer starts with command and address */

	buf_size = at25->chip.page_size;

	buf_size = at25->chip.page_size;

	if (buf_size > io_limit)

	if (buf_size > io_limit)
@@ -253,18 +261,31 @@ at25_bin_write(struct kobject *kobj, struct bin_attribute *bin_attr, 
	dev = container_of(kobj, struct device, kobj);

	dev = container_of(kobj, struct device, kobj);

	at25 = dev_get_drvdata(dev);

	at25 = dev_get_drvdata(dev);





	if (unlikely(off >= at25->bin.size))

		return -EFBIG;

	if ((off + count) > at25->bin.size)

		count = at25->bin.size - off;

	if (unlikely(!count))

		return count;



	return at25_ee_write(at25, buf, off, count);

	return at25_ee_write(at25, buf, off, count);

}

}





/*-------------------------------------------------------------------------*/

/*-------------------------------------------------------------------------*/





/* Let in-kernel code access the eeprom data. */



static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,

			 off_t offset, size_t count)

{

	struct at25_data *at25 = container_of(mem, struct at25_data, mem);



	return at25_ee_read(at25, buf, offset, count);

}



static ssize_t at25_mem_write(struct memory_accessor *mem, char *buf,

			  off_t offset, size_t count)

{

	struct at25_data *at25 = container_of(mem, struct at25_data, mem);



	return at25_ee_write(at25, buf, offset, count);

}



/*-------------------------------------------------------------------------*/



static int at25_probe(struct spi_device *spi)

static int at25_probe(struct spi_device *spi)

{

{

	struct at25_data	*at25 = NULL;

	struct at25_data	*at25 = NULL;
@@ -317,6 +338,10 @@ static int at25_probe(struct spi_device *spi) 
	at25->addrlen = addrlen;

	at25->addrlen = addrlen;





	/* Export the EEPROM bytes through sysfs, since that's convenient.

	/* Export the EEPROM bytes through sysfs, since that's convenient.

	 * And maybe to other kernel code; it might hold a board's Ethernet

	 * address, or board-specific calibration data generated on the

	 * manufacturing floor.

	 *

	 * Default to root-only access to the data; EEPROMs often hold data

	 * Default to root-only access to the data; EEPROMs often hold data

	 * that's sensitive for read and/or write, like ethernet addresses,

	 * that's sensitive for read and/or write, like ethernet addresses,

	 * security codes, board-specific manufacturing calibrations, etc.

	 * security codes, board-specific manufacturing calibrations, etc.
@@ -324,17 +349,22 @@ static int at25_probe(struct spi_device *spi) 
	at25->bin.attr.name = "eeprom";

	at25->bin.attr.name = "eeprom";

	at25->bin.attr.mode = S_IRUSR;

	at25->bin.attr.mode = S_IRUSR;

	at25->bin.read = at25_bin_read;

	at25->bin.read = at25_bin_read;

	at25->mem.read = at25_mem_read;





	at25->bin.size = at25->chip.byte_len;

	at25->bin.size = at25->chip.byte_len;

	if (!(chip->flags & EE_READONLY)) {

	if (!(chip->flags & EE_READONLY)) {

		at25->bin.write = at25_bin_write;

		at25->bin.write = at25_bin_write;

		at25->bin.attr.mode |= S_IWUSR;

		at25->bin.attr.mode |= S_IWUSR;

		at25->mem.write = at25_mem_write;

	}

	}





	err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);

	err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);

	if (err)

	if (err)

		goto fail;

		goto fail;





	if (chip->setup)

		chip->setup(&at25->mem, chip->context);



	dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",

	dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",

		(at25->bin.size < 1024)

		(at25->bin.size < 1024)

			? at25->bin.size

			? at25->bin.size

include/linux/spi/eeprom.h

+6 −0
Original line number Original line Diff line number Diff line 
#ifndef __LINUX_SPI_EEPROM_H

#ifndef __LINUX_SPI_EEPROM_H

#define __LINUX_SPI_EEPROM_H

#define __LINUX_SPI_EEPROM_H





#include <linux/memory.h>



/*

/*

 * Put one of these structures in platform_data for SPI EEPROMS handled

 * Put one of these structures in platform_data for SPI EEPROMS handled

 * by the "at25" driver.  On SPI, most EEPROMS understand the same core

 * by the "at25" driver.  On SPI, most EEPROMS understand the same core
@@ -17,6 +19,10 @@ struct spi_eeprom { 
#define	EE_ADDR2	0x0002			/* 16 bit addrs */

#define	EE_ADDR2	0x0002			/* 16 bit addrs */

#define	EE_ADDR3	0x0004			/* 24 bit addrs */

#define	EE_ADDR3	0x0004			/* 24 bit addrs */

#define	EE_READONLY	0x0008			/* disallow writes */

#define	EE_READONLY	0x0008			/* disallow writes */



	/* for exporting this chip's data to other kernel code */

	void (*setup)(struct memory_accessor *mem, void *context);

	void *context;

};

};





#endif /* __LINUX_SPI_EEPROM_H */
 
#endif /* __LINUX_SPI_EEPROM_H */