[net-next-2.6.git] / drivers / w1 / slaves / w1_ds2433.c

/*
 *	w1_ds2433.c - w1 family 23 (DS2433) driver
 *
 * Copyright (c) 2005 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/slab.h>
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
#include <linux/crc16.h>

#define CRC16_INIT		0
#define CRC16_VALID		0xb001

#endif

#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");

#define W1_EEPROM_SIZE		512
#define W1_PAGE_COUNT		16
#define W1_PAGE_SIZE		32
#define W1_PAGE_BITS		5
#define W1_PAGE_MASK		0x1F

#define W1_F23_TIME		300

#define W1_F23_READ_EEPROM	0xF0
#define W1_F23_WRITE_SCRATCH	0x0F
#define W1_F23_READ_SCRATCH	0xAA
#define W1_F23_COPY_SCRATCH	0x55

struct w1_f23_data {
	u8	memory[W1_EEPROM_SIZE];
	u32	validcrc;
};

/**
 * 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_f23_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;
}

#ifdef CONFIG_W1_SLAVE_DS2433_CRC
static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
				int block)
{
	u8	wrbuf[3];
	int	off = block * W1_PAGE_SIZE;

	if (data->validcrc & (1 << block))
		return 0;

	if (w1_reset_select_slave(sl)) {
		data->validcrc = 0;
		return -EIO;
	}

	wrbuf[0] = W1_F23_READ_EEPROM;
	wrbuf[1] = off & 0xff;
	wrbuf[2] = off >> 8;
	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);

	/* cache the block if the CRC is valid */
	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
		data->validcrc |= (1 << block);

	return 0;
}
#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */

static ssize_t w1_f23_read_bin(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);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	struct w1_f23_data *data = sl->family_data;
	int i, min_page, max_page;
#else
	u8 wrbuf[3];
#endif

	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
		return 0;

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

#ifdef CONFIG_W1_SLAVE_DS2433_CRC

	min_page = (off >> W1_PAGE_BITS);
	max_page = (off + count - 1) >> W1_PAGE_BITS;
	for (i = min_page; i <= max_page; i++) {
		if (w1_f23_refresh_block(sl, data, i)) {
			count = -EIO;
			goto out_up;
		}
	}
	memcpy(buf, &data->memory[off], count);

#else 	/* CONFIG_W1_SLAVE_DS2433_CRC */

	/* read directly from the EEPROM */
	if (w1_reset_select_slave(sl)) {
		count = -EIO;
		goto out_up;
	}

	wrbuf[0] = W1_F23_READ_EEPROM;
	wrbuf[1] = off & 0xff;
	wrbuf[2] = off >> 8;
	w1_write_block(sl->master, wrbuf, 3);
	w1_read_block(sl->master, buf, count);

#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */

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

	return count;
}

/**
 * Writes to the scratchpad and reads it back for verification.
 * Then copies the scratchpad to EEPROM.
 * The data must be on one page.
 * The master must be locked.
 *
 * @param sl	The slave structure
 * @param addr	Address for the write
 * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 * @param data	The data to write
 * @return	0=Success -1=failure
 */
static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	struct w1_f23_data *f23 = sl->family_data;
#endif
	u8 wrbuf[4];
	u8 rdbuf[W1_PAGE_SIZE + 3];
	u8 es = (addr + len - 1) & 0x1f;

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

	wrbuf[0] = W1_F23_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_F23_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))
		return -1;

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

	wrbuf[0] = W1_F23_COPY_SCRATCH;
	wrbuf[3] = es;
	w1_write_block(sl->master, wrbuf, 4);

	/* Sleep for 5 ms to wait for the write to complete */
	msleep(5);

	/* Reset the bus to wake up the EEPROM (this may not be needed) */
	w1_reset_bus(sl->master);
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
#endif
	return 0;
}

static ssize_t w1_f23_write_bin(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, idx;

	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
		return 0;

#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	/* can only write full blocks in cached mode */
	if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
		dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
			(int)off, count);
		return -EINVAL;
	}

	/* make sure the block CRCs are valid */
	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
		if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
			dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
			return -EINVAL;
		}
	}
#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */

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

	/* Can only write data to one page at a time */
	idx = 0;
	while (idx < count) {
		addr = off + idx;
		len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
		if (len > (count - idx))
			len = count - idx;

		if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
			count = -EIO;
			goto out_up;
		}
		idx += len;
	}

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

	return count;
}

static struct bin_attribute w1_f23_bin_attr = {
	.attr = {
		.name = "eeprom",
		.mode = S_IRUGO | S_IWUSR,
	},
	.size = W1_EEPROM_SIZE,
	.read = w1_f23_read_bin,
	.write = w1_f23_write_bin,
};

static int w1_f23_add_slave(struct w1_slave *sl)
{
	int err;
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	struct w1_f23_data *data;

	data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;
	sl->family_data = data;

#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */

	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);

#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	if (err)
		kfree(data);
#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */

	return err;
}

static void w1_f23_remove_slave(struct w1_slave *sl)
{
#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	kfree(sl->family_data);
	sl->family_data = NULL;
#endif	/* CONFIG_W1_SLAVE_DS2433_CRC */
	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}

static struct w1_family_ops w1_f23_fops = {
	.add_slave      = w1_f23_add_slave,
	.remove_slave   = w1_f23_remove_slave,
};

static struct w1_family w1_family_23 = {
	.fid = W1_EEPROM_DS2433,
	.fops = &w1_f23_fops,
};

static int __init w1_f23_init(void)
{
	return w1_register_family(&w1_family_23);
}

static void __exit w1_f23_fini(void)
{
	w1_unregister_family(&w1_family_23);
}

module_init(w1_f23_init);
module_exit(w1_f23_fini);
Commit	Line	Data
	1	/*
	2	* w1_ds2433.c - w1 family 23 (DS2433) driver
	3	*
	4	* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
	5	*
	6	* This source code is licensed under the GNU General Public License,
	7	* Version 2. See the file COPYING for more details.
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/module.h>
	12	#include <linux/moduleparam.h>
	13	#include <linux/device.h>
	14	#include <linux/types.h>
	15	#include <linux/delay.h>
	16	#include <linux/slab.h>
	17	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	18	#include <linux/crc16.h>
	19
	20	#define CRC16_INIT 0
	21	#define CRC16_VALID 0xb001
	22
	23	#endif
	24
	25	#include "../w1.h"
	26	#include "../w1_int.h"
	27	#include "../w1_family.h"
	28
	29	MODULE_LICENSE("GPL");
	30	MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
	31	MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
	32
	33	#define W1_EEPROM_SIZE 512
	34	#define W1_PAGE_COUNT 16
	35	#define W1_PAGE_SIZE 32
	36	#define W1_PAGE_BITS 5
	37	#define W1_PAGE_MASK 0x1F
	38
	39	#define W1_F23_TIME 300
	40
	41	#define W1_F23_READ_EEPROM 0xF0
	42	#define W1_F23_WRITE_SCRATCH 0x0F
	43	#define W1_F23_READ_SCRATCH 0xAA
	44	#define W1_F23_COPY_SCRATCH 0x55
	45
	46	struct w1_f23_data {
	47	u8 memory[W1_EEPROM_SIZE];
	48	u32 validcrc;
	49	};
	50
	51	/**
	52	* Check the file size bounds and adjusts count as needed.
	53	* This would not be needed if the file size didn't reset to 0 after a write.
	54	*/
	55	static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
	56	{
	57	if (off > size)
	58	return 0;
	59
	60	if ((off + count) > size)
	61	return (size - off);
	62
	63	return count;
	64	}
	65
	66	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	67	static int w1_f23_refresh_block(struct w1_slave sl, struct w1_f23_data data,
	68	int block)
	69	{
	70	u8 wrbuf[3];
	71	int off = block * W1_PAGE_SIZE;
	72
	73	if (data->validcrc & (1 << block))
	74	return 0;
	75
	76	if (w1_reset_select_slave(sl)) {
	77	data->validcrc = 0;
	78	return -EIO;
	79	}
	80
	81	wrbuf[0] = W1_F23_READ_EEPROM;
	82	wrbuf[1] = off & 0xff;
	83	wrbuf[2] = off >> 8;
	84	w1_write_block(sl->master, wrbuf, 3);
	85	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
	86
	87	/* cache the block if the CRC is valid */
	88	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
	89	data->validcrc \|= (1 << block);
	90
	91	return 0;
	92	}
	93	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	94
	95	static ssize_t w1_f23_read_bin(struct kobject *kobj,
	96	struct bin_attribute *bin_attr,
	97	char *buf, loff_t off, size_t count)
	98	{
	99	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	100	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	101	struct w1_f23_data *data = sl->family_data;
	102	int i, min_page, max_page;
	103	#else
	104	u8 wrbuf[3];
	105	#endif
	106
	107	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	108	return 0;
	109
	110	mutex_lock(&sl->master->mutex);
	111
	112	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	113
	114	min_page = (off >> W1_PAGE_BITS);
	115	max_page = (off + count - 1) >> W1_PAGE_BITS;
	116	for (i = min_page; i <= max_page; i++) {
	117	if (w1_f23_refresh_block(sl, data, i)) {
	118	count = -EIO;
	119	goto out_up;
	120	}
	121	}
	122	memcpy(buf, &data->memory[off], count);
	123
	124	#else /* CONFIG_W1_SLAVE_DS2433_CRC */
	125
	126	/* read directly from the EEPROM */
	127	if (w1_reset_select_slave(sl)) {
	128	count = -EIO;
	129	goto out_up;
	130	}
	131
	132	wrbuf[0] = W1_F23_READ_EEPROM;
	133	wrbuf[1] = off & 0xff;
	134	wrbuf[2] = off >> 8;
	135	w1_write_block(sl->master, wrbuf, 3);
	136	w1_read_block(sl->master, buf, count);
	137
	138	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	139
	140	out_up:
	141	mutex_unlock(&sl->master->mutex);
	142
	143	return count;
	144	}
	145
	146	/**
	147	* Writes to the scratchpad and reads it back for verification.
	148	* Then copies the scratchpad to EEPROM.
	149	* The data must be on one page.
	150	* The master must be locked.
	151	*
	152	* @param sl The slave structure
	153	* @param addr Address for the write
	154	* @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
	155	* @param data The data to write
	156	* @return 0=Success -1=failure
	157	*/
	158	static int w1_f23_write(struct w1_slave sl, int addr, int len, const u8 data)
	159	{
	160	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	161	struct w1_f23_data *f23 = sl->family_data;
	162	#endif
	163	u8 wrbuf[4];
	164	u8 rdbuf[W1_PAGE_SIZE + 3];
	165	u8 es = (addr + len - 1) & 0x1f;
	166
	167	/* Write the data to the scratchpad */
	168	if (w1_reset_select_slave(sl))
	169	return -1;
	170
	171	wrbuf[0] = W1_F23_WRITE_SCRATCH;
	172	wrbuf[1] = addr & 0xff;
	173	wrbuf[2] = addr >> 8;
	174
	175	w1_write_block(sl->master, wrbuf, 3);
	176	w1_write_block(sl->master, data, len);
	177
	178	/* Read the scratchpad and verify */
	179	if (w1_reset_select_slave(sl))
	180	return -1;
	181
	182	w1_write_8(sl->master, W1_F23_READ_SCRATCH);
	183	w1_read_block(sl->master, rdbuf, len + 3);
	184
	185	/* Compare what was read against the data written */
	186	if ((rdbuf[0] != wrbuf[1]) \|\| (rdbuf[1] != wrbuf[2]) \|\|
	187	(rdbuf[2] != es) \|\| (memcmp(data, &rdbuf[3], len) != 0))
	188	return -1;
	189
	190	/* Copy the scratchpad to EEPROM */
	191	if (w1_reset_select_slave(sl))
	192	return -1;
	193
	194	wrbuf[0] = W1_F23_COPY_SCRATCH;
	195	wrbuf[3] = es;
	196	w1_write_block(sl->master, wrbuf, 4);
	197
	198	/* Sleep for 5 ms to wait for the write to complete */
	199	msleep(5);
	200
	201	/* Reset the bus to wake up the EEPROM (this may not be needed) */
	202	w1_reset_bus(sl->master);
	203	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	204	f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
	205	#endif
	206	return 0;
	207	}
	208
	209	static ssize_t w1_f23_write_bin(struct kobject *kobj,
	210	struct bin_attribute *bin_attr,
	211	char *buf, loff_t off, size_t count)
	212	{
	213	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	214	int addr, len, idx;
	215
	216	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	217	return 0;
	218
	219	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	220	/* can only write full blocks in cached mode */
	221	if ((off & W1_PAGE_MASK) \|\| (count & W1_PAGE_MASK)) {
	222	dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
	223	(int)off, count);
	224	return -EINVAL;
	225	}
	226
	227	/* make sure the block CRCs are valid */
	228	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
	229	if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
	230	dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
	231	return -EINVAL;
	232	}
	233	}
	234	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	235
	236	mutex_lock(&sl->master->mutex);
	237
	238	/* Can only write data to one page at a time */
	239	idx = 0;
	240	while (idx < count) {
	241	addr = off + idx;
	242	len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
	243	if (len > (count - idx))
	244	len = count - idx;
	245
	246	if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
	247	count = -EIO;
	248	goto out_up;
	249	}
	250	idx += len;
	251	}
	252
	253	out_up:
	254	mutex_unlock(&sl->master->mutex);
	255
	256	return count;
	257	}
	258
	259	static struct bin_attribute w1_f23_bin_attr = {
	260	.attr = {
	261	.name = "eeprom",
	262	.mode = S_IRUGO \| S_IWUSR,
	263	},
	264	.size = W1_EEPROM_SIZE,
	265	.read = w1_f23_read_bin,
	266	.write = w1_f23_write_bin,
	267	};
	268
	269	static int w1_f23_add_slave(struct w1_slave *sl)
	270	{
	271	int err;
	272	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	273	struct w1_f23_data *data;
	274
	275	data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	276	if (!data)
	277	return -ENOMEM;
	278	sl->family_data = data;
	279
	280	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	281
	282	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	283
	284	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	285	if (err)
	286	kfree(data);
	287	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	288
	289	return err;
	290	}
	291
	292	static void w1_f23_remove_slave(struct w1_slave *sl)
	293	{
	294	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
	295	kfree(sl->family_data);
	296	sl->family_data = NULL;
	297	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
	298	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	299	}
	300
	301	static struct w1_family_ops w1_f23_fops = {
	302	.add_slave = w1_f23_add_slave,
	303	.remove_slave = w1_f23_remove_slave,
	304	};
	305
	306	static struct w1_family w1_family_23 = {
	307	.fid = W1_EEPROM_DS2433,
	308	.fops = &w1_f23_fops,
	309	};
	310
	311	static int __init w1_f23_init(void)
	312	{
	313	return w1_register_family(&w1_family_23);
	314	}
	315
	316	static void __exit w1_f23_fini(void)
	317	{
	318	w1_unregister_family(&w1_family_23);
	319	}
	320
	321	module_init(w1_f23_init);
	322	module_exit(w1_f23_fini);