drivers/w1/slaves/w1_ds2431.c - third_party/kernel - Git at Google

 /*
  * w1_ds2431.c - w1 family 2d (DS2431) driver
  *
  * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
  *
  * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com>
  *
  * This source code is licensed under the GNU General Public License,
  * Version 2. See the file COPYING for more details.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/device.h>
 #include <linux/types.h>
 #include <linux/delay.h>

 #include <linux/w1.h>

 #define W1_EEPROM_DS2431	0x2D

 #define W1_F2D_EEPROM_SIZE		128
 #define W1_F2D_PAGE_COUNT		4
 #define W1_F2D_PAGE_BITS		5
 #define W1_F2D_PAGE_SIZE		(1<<W1_F2D_PAGE_BITS)
 #define W1_F2D_PAGE_MASK		0x1F

 #define W1_F2D_SCRATCH_BITS  3
 #define W1_F2D_SCRATCH_SIZE  (1<<W1_F2D_SCRATCH_BITS)
 #define W1_F2D_SCRATCH_MASK  (W1_F2D_SCRATCH_SIZE-1)

 #define W1_F2D_READ_EEPROM	0xF0
 #define W1_F2D_WRITE_SCRATCH	0x0F
 #define W1_F2D_READ_SCRATCH	0xAA
 #define W1_F2D_COPY_SCRATCH	0x55


 #define W1_F2D_TPROG_MS		11

 #define W1_F2D_READ_RETRIES		10
 #define W1_F2D_READ_MAXLEN		8

 /*
  * Check the file size bounds and adjusts count as needed.
  * This would not be needed if the file size didn't reset to 0 after a write.
  */
 static inline size_t w1_f2d_fix_count(loff_t off, size_t count, size_t size)
 {
 	if (off > size)
 		return 0;

 	if ((off + count) > size)
 		return size - off;

 	return count;
 }

 /*
  * Read a block from W1 ROM two times and compares the results.
  * If they are equal they are returned, otherwise the read
  * is repeated W1_F2D_READ_RETRIES times.
  *
  * count must not exceed W1_F2D_READ_MAXLEN.
  */
 static int w1_f2d_readblock(struct w1_slave *sl, int off, int count, char *buf)
 {
 	u8 wrbuf[3];
 	u8 cmp[W1_F2D_READ_MAXLEN];
 	int tries = W1_F2D_READ_RETRIES;

 	do {
 		wrbuf[0] = W1_F2D_READ_EEPROM;
 		wrbuf[1] = off & 0xff;
 		wrbuf[2] = off >> 8;

 		if (w1_reset_select_slave(sl))
 			return -1;

 		w1_write_block(sl->master, wrbuf, 3);
 		w1_read_block(sl->master, buf, count);

 		if (w1_reset_select_slave(sl))
 			return -1;

 		w1_write_block(sl->master, wrbuf, 3);
 		w1_read_block(sl->master, cmp, count);

 		if (!memcmp(cmp, buf, count))
 			return 0;
 	} while (--tries);

 	dev_err(&sl->dev, "proof reading failed %d times\n",
 			W1_F2D_READ_RETRIES);

 	return -1;
 }

 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
 			   struct bin_attribute *bin_attr, char *buf,
 			   loff_t off, size_t count)
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	int todo = count;

 	count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
 	if (count == 0)
 		return 0;

 	mutex_lock(&sl->master->bus_mutex);

 	/* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
 	while (todo > 0) {
 		int block_read;

 		if (todo >= W1_F2D_READ_MAXLEN)
 			block_read = W1_F2D_READ_MAXLEN;
 		else
 			block_read = todo;

 		if (w1_f2d_readblock(sl, off, block_read, buf) < 0)
 			count = -EIO;

 		todo -= W1_F2D_READ_MAXLEN;
 		buf += W1_F2D_READ_MAXLEN;
 		off += W1_F2D_READ_MAXLEN;
 	}

 	mutex_unlock(&sl->master->bus_mutex);

 	return count;
 }

 /*
  * Writes to the scratchpad and reads it back for verification.
  * Then copies the scratchpad to EEPROM.
  * The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and
  * must be W1_F2D_SCRATCH_SIZE bytes long.
  * The master must be locked.
  *
  * @param sl	The slave structure
  * @param addr	Address for the write
  * @param len   length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
  * @param data	The data to write
  * @return	0=Success -1=failure
  */
 static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 {
 	int tries = W1_F2D_READ_RETRIES;
 	u8 wrbuf[4];
 	u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
 	u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;

 retry:

 	/* Write the data to the scratchpad */
 	if (w1_reset_select_slave(sl))
 		return -1;

 	wrbuf[0] = W1_F2D_WRITE_SCRATCH;
 	wrbuf[1] = addr & 0xff;
 	wrbuf[2] = addr >> 8;

 	w1_write_block(sl->master, wrbuf, 3);
 	w1_write_block(sl->master, data, len);

 	/* Read the scratchpad and verify */
 	if (w1_reset_select_slave(sl))
 		return -1;

 	w1_write_8(sl->master, W1_F2D_READ_SCRATCH);
 	w1_read_block(sl->master, rdbuf, len + 3);

 	/* Compare what was read against the data written */
 	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) {

 		if (--tries)
 			goto retry;

 		dev_err(&sl->dev,
 			"could not write to eeprom, scratchpad compare failed %d times\n",
 			W1_F2D_READ_RETRIES);

 		return -1;
 	}

 	/* Copy the scratchpad to EEPROM */
 	if (w1_reset_select_slave(sl))
 		return -1;

 	wrbuf[0] = W1_F2D_COPY_SCRATCH;
 	wrbuf[3] = es;
 	w1_write_block(sl->master, wrbuf, 4);

 	/* Sleep for tprog ms to wait for the write to complete */
 	msleep(W1_F2D_TPROG_MS);

 	/* Reset the bus to wake up the EEPROM  */
 	w1_reset_bus(sl->master);

 	return 0;
 }

 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 			    struct bin_attribute *bin_attr, char *buf,
 			    loff_t off, size_t count)
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	int addr, len;
 	int copy;

 	count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
 	if (count == 0)
 		return 0;

 	mutex_lock(&sl->master->bus_mutex);

 	/* Can only write data in blocks of the size of the scratchpad */
 	addr = off;
 	len = count;
 	while (len > 0) {

 		/* if len too short or addr not aligned */
 		if (len < W1_F2D_SCRATCH_SIZE || addr & W1_F2D_SCRATCH_MASK) {
 			char tmp[W1_F2D_SCRATCH_SIZE];

 			/* read the block and update the parts to be written */
 			if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK,
 					W1_F2D_SCRATCH_SIZE, tmp)) {
 				count = -EIO;
 				goto out_up;
 			}

 			/* copy at most to the boundary of the PAGE or len */
 			copy = W1_F2D_SCRATCH_SIZE -
 				(addr & W1_F2D_SCRATCH_MASK);

 			if (copy > len)
 				copy = len;

 			memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy);
 			if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK,
 					W1_F2D_SCRATCH_SIZE, tmp) < 0) {
 				count = -EIO;
 				goto out_up;
 			}
 		} else {

 			copy = W1_F2D_SCRATCH_SIZE;
 			if (w1_f2d_write(sl, addr, copy, buf) < 0) {
 				count = -EIO;
 				goto out_up;
 			}
 		}
 		buf += copy;
 		addr += copy;
 		len -= copy;
 	}

 out_up:
 	mutex_unlock(&sl->master->bus_mutex);

 	return count;
 }

 static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE);

 static struct bin_attribute *w1_f2d_bin_attrs[] = {
 	&bin_attr_eeprom,
 	NULL,
 };

 static const struct attribute_group w1_f2d_group = {
 	.bin_attrs = w1_f2d_bin_attrs,
 };

 static const struct attribute_group *w1_f2d_groups[] = {
 	&w1_f2d_group,
 	NULL,
 };

 static struct w1_family_ops w1_f2d_fops = {
 	.groups		= w1_f2d_groups,
 };

 static struct w1_family w1_family_2d = {
 	.fid = W1_EEPROM_DS2431,
 	.fops = &w1_f2d_fops,
 };
 module_w1_family(w1_family_2d);

 MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>");
 MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431));
	/*
	* w1_ds2431.c - w1 family 2d (DS2431) driver
	*
	* Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
	*
	* Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com>
	*
	* This source code is licensed under the GNU General Public License,
	* Version 2. See the file COPYING for more details.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/device.h>
	#include <linux/types.h>
	#include <linux/delay.h>

	#include <linux/w1.h>

	#define W1_EEPROM_DS2431 0x2D

	#define W1_F2D_EEPROM_SIZE 128
	#define W1_F2D_PAGE_COUNT 4
	#define W1_F2D_PAGE_BITS 5
	#define W1_F2D_PAGE_SIZE (1<<W1_F2D_PAGE_BITS)
	#define W1_F2D_PAGE_MASK 0x1F

	#define W1_F2D_SCRATCH_BITS 3
	#define W1_F2D_SCRATCH_SIZE (1<<W1_F2D_SCRATCH_BITS)
	#define W1_F2D_SCRATCH_MASK (W1_F2D_SCRATCH_SIZE-1)

	#define W1_F2D_READ_EEPROM 0xF0
	#define W1_F2D_WRITE_SCRATCH 0x0F
	#define W1_F2D_READ_SCRATCH 0xAA
	#define W1_F2D_COPY_SCRATCH 0x55


	#define W1_F2D_TPROG_MS 11

	#define W1_F2D_READ_RETRIES 10
	#define W1_F2D_READ_MAXLEN 8

	/*
	* Check the file size bounds and adjusts count as needed.
	* This would not be needed if the file size didn't reset to 0 after a write.
	*/
	static inline size_t w1_f2d_fix_count(loff_t off, size_t count, size_t size)
	{
	if (off > size)
	return 0;

	if ((off + count) > size)
	return size - off;

	return count;
	}

	/*
	* Read a block from W1 ROM two times and compares the results.
	* If they are equal they are returned, otherwise the read
	* is repeated W1_F2D_READ_RETRIES times.
	*
	* count must not exceed W1_F2D_READ_MAXLEN.
	*/
	static int w1_f2d_readblock(struct w1_slave sl, int off, int count, char buf)
	{
	u8 wrbuf[3];
	u8 cmp[W1_F2D_READ_MAXLEN];
	int tries = W1_F2D_READ_RETRIES;

	do {
	wrbuf[0] = W1_F2D_READ_EEPROM;
	wrbuf[1] = off & 0xff;
	wrbuf[2] = off >> 8;

	if (w1_reset_select_slave(sl))
	return -1;

	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, buf, count);

	if (w1_reset_select_slave(sl))
	return -1;

	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, cmp, count);

	if (!memcmp(cmp, buf, count))
	return 0;
	} while (--tries);

	dev_err(&sl->dev, "proof reading failed %d times\n",
	W1_F2D_READ_RETRIES);

	return -1;
	}

	static ssize_t eeprom_read(struct file filp, struct kobject kobj,
	struct bin_attribute bin_attr, char buf,
	loff_t off, size_t count)
	{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	int todo = count;

	count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
	if (count == 0)
	return 0;

	mutex_lock(&sl->master->bus_mutex);

	/* read directly from the EEPROM in chunks of W1_F2D_READ_MAXLEN */
	while (todo > 0) {
	int block_read;

	if (todo >= W1_F2D_READ_MAXLEN)
	block_read = W1_F2D_READ_MAXLEN;
	else
	block_read = todo;

	if (w1_f2d_readblock(sl, off, block_read, buf) < 0)
	count = -EIO;

	todo -= W1_F2D_READ_MAXLEN;
	buf += W1_F2D_READ_MAXLEN;
	off += W1_F2D_READ_MAXLEN;
	}

	mutex_unlock(&sl->master->bus_mutex);

	return count;
	}

	/*
	* Writes to the scratchpad and reads it back for verification.
	* Then copies the scratchpad to EEPROM.
	* The data must be aligned at W1_F2D_SCRATCH_SIZE bytes and
	* must be W1_F2D_SCRATCH_SIZE bytes long.
	* The master must be locked.
	*
	* @param sl The slave structure
	* @param addr Address for the write
	* @param len length must be <= (W1_F2D_PAGE_SIZE - (addr & W1_F2D_PAGE_MASK))
	* @param data The data to write
	* @return 0=Success -1=failure
	*/
	static int w1_f2d_write(struct w1_slave sl, int addr, int len, const u8 data)
	{
	int tries = W1_F2D_READ_RETRIES;
	u8 wrbuf[4];
	u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
	u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;

	retry:

	/* Write the data to the scratchpad */
	if (w1_reset_select_slave(sl))
	return -1;

	wrbuf[0] = W1_F2D_WRITE_SCRATCH;
	wrbuf[1] = addr & 0xff;
	wrbuf[2] = addr >> 8;

	w1_write_block(sl->master, wrbuf, 3);
	w1_write_block(sl->master, data, len);

	/* Read the scratchpad and verify */
	if (w1_reset_select_slave(sl))
	return -1;

	w1_write_8(sl->master, W1_F2D_READ_SCRATCH);
	w1_read_block(sl->master, rdbuf, len + 3);

	/* Compare what was read against the data written */
	if ((rdbuf[0] != wrbuf[1]) \|\| (rdbuf[1] != wrbuf[2]) \|\|
	(rdbuf[2] != es) \|\| (memcmp(data, &rdbuf[3], len) != 0)) {

	if (--tries)
	goto retry;

	dev_err(&sl->dev,
	"could not write to eeprom, scratchpad compare failed %d times\n",
	W1_F2D_READ_RETRIES);

	return -1;
	}

	/* Copy the scratchpad to EEPROM */
	if (w1_reset_select_slave(sl))
	return -1;

	wrbuf[0] = W1_F2D_COPY_SCRATCH;
	wrbuf[3] = es;
	w1_write_block(sl->master, wrbuf, 4);

	/* Sleep for tprog ms to wait for the write to complete */
	msleep(W1_F2D_TPROG_MS);

	/* Reset the bus to wake up the EEPROM */
	w1_reset_bus(sl->master);

	return 0;
	}

	static ssize_t eeprom_write(struct file filp, struct kobject kobj,
	struct bin_attribute bin_attr, char buf,
	loff_t off, size_t count)
	{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	int addr, len;
	int copy;

	count = w1_f2d_fix_count(off, count, W1_F2D_EEPROM_SIZE);
	if (count == 0)
	return 0;

	mutex_lock(&sl->master->bus_mutex);

	/* Can only write data in blocks of the size of the scratchpad */
	addr = off;
	len = count;
	while (len > 0) {

	/* if len too short or addr not aligned */
	if (len < W1_F2D_SCRATCH_SIZE \|\| addr & W1_F2D_SCRATCH_MASK) {
	char tmp[W1_F2D_SCRATCH_SIZE];

	/* read the block and update the parts to be written */
	if (w1_f2d_readblock(sl, addr & ~W1_F2D_SCRATCH_MASK,
	W1_F2D_SCRATCH_SIZE, tmp)) {
	count = -EIO;
	goto out_up;
	}

	/* copy at most to the boundary of the PAGE or len */
	copy = W1_F2D_SCRATCH_SIZE -
	(addr & W1_F2D_SCRATCH_MASK);

	if (copy > len)
	copy = len;

	memcpy(&tmp[addr & W1_F2D_SCRATCH_MASK], buf, copy);
	if (w1_f2d_write(sl, addr & ~W1_F2D_SCRATCH_MASK,
	W1_F2D_SCRATCH_SIZE, tmp) < 0) {
	count = -EIO;
	goto out_up;
	}
	} else {

	copy = W1_F2D_SCRATCH_SIZE;
	if (w1_f2d_write(sl, addr, copy, buf) < 0) {
	count = -EIO;
	goto out_up;
	}
	}
	buf += copy;
	addr += copy;
	len -= copy;
	}

	out_up:
	mutex_unlock(&sl->master->bus_mutex);

	return count;
	}

	static BIN_ATTR_RW(eeprom, W1_F2D_EEPROM_SIZE);

	static struct bin_attribute *w1_f2d_bin_attrs[] = {
	&bin_attr_eeprom,
	NULL,
	};

	static const struct attribute_group w1_f2d_group = {
	.bin_attrs = w1_f2d_bin_attrs,
	};

	static const struct attribute_group *w1_f2d_groups[] = {
	&w1_f2d_group,
	NULL,
	};

	static struct w1_family_ops w1_f2d_fops = {
	.groups = w1_f2d_groups,
	};

	static struct w1_family w1_family_2d = {
	.fid = W1_EEPROM_DS2431,
	.fops = &w1_f2d_fops,
	};
	module_w1_family(w1_family_2d);

	MODULE_AUTHOR("Bernhard Weirich <bernhard.weirich@riedel.net>");
	MODULE_DESCRIPTION("w1 family 2d driver for DS2431, 1kb EEPROM");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2431));