[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>
#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, 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)
{
	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);

	return 0;
}

static ssize_t w1_f23_write_bin(struct kobject *kobj, 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 = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;
	memset(data, 0, sizeof(struct w1_f23_data));
	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
80895392 EP	1	/*
	2	* w1_ds2433.c - w1 family 23 (DS2433) driver
	3	*
	4	* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
	5	*
0a25e4d5 EP	6	* This source code is licensed under the GNU General Public License,
0a25e4d5 EP	7	* Version 2. See the file COPYING for more details.
80895392 EP	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>
e9d55f9d	16	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5	17	#include <linux/crc16.h>
f24ec7f6 EP	18
	19	#define CRC16_INIT 0
	20	#define CRC16_VALID 0xb001
	21
0a25e4d5	22	#endif
80895392	23
bd529cfb	24	#include "../w1.h"
bd529cfb EP	25	#include "../w1_int.h"
bd529cfb EP	26	#include "../w1_family.h"
80895392 EP	27
	28	MODULE_LICENSE("GPL");
	29	MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
	30	MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
	31
	32	#define W1_EEPROM_SIZE 512
0a25e4d5	33	#define W1_PAGE_COUNT 16
80895392 EP	34	#define W1_PAGE_SIZE 32
	35	#define W1_PAGE_BITS 5
	36	#define W1_PAGE_MASK 0x1F
	37
0a25e4d5 EP	38	#define W1_F23_TIME 300
0a25e4d5 EP	39
80895392 EP	40	#define W1_F23_READ_EEPROM 0xF0
	41	#define W1_F23_WRITE_SCRATCH 0x0F
	42	#define W1_F23_READ_SCRATCH 0xAA
	43	#define W1_F23_COPY_SCRATCH 0x55
	44
0a25e4d5 EP	45	struct w1_f23_data {
	46	u8 memory[W1_EEPROM_SIZE];
	47	u32 validcrc;
	48	};
	49
80895392 EP	50	/**
80895392 EP	51	* Check the file size bounds and adjusts count as needed.
0a25e4d5	52	* This would not be needed if the file size didn't reset to 0 after a write.
80895392 EP	53	*/
	54	static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
	55	{
	56	if (off > size)
	57	return 0;
	58
	59	if ((off + count) > size)
	60	return (size - off);
	61
	62	return count;
	63	}
	64
e9d55f9d	65	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	66	static int w1_f23_refresh_block(struct w1_slave sl, struct w1_f23_data data,
	67	int block)
	68	{
	69	u8 wrbuf[3];
	70	int off = block * W1_PAGE_SIZE;
	71
	72	if (data->validcrc & (1 << block))
	73	return 0;
	74
	75	if (w1_reset_select_slave(sl)) {
	76	data->validcrc = 0;
	77	return -EIO;
	78	}
	79
	80	wrbuf[0] = W1_F23_READ_EEPROM;
	81	wrbuf[1] = off & 0xff;
	82	wrbuf[2] = off >> 8;
	83	w1_write_block(sl->master, wrbuf, 3);
	84	w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
	85
	86	/* cache the block if the CRC is valid */
	87	if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
	88	data->validcrc \|= (1 << block);
	89
	90	return 0;
	91	}
e9d55f9d	92	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5 EP	93
	94	static ssize_t w1_f23_read_bin(struct kobject kobj, char buf, loff_t off,
	95	size_t count)
80895392 EP	96	{
80895392 EP	97	struct w1_slave *sl = kobj_to_w1_slave(kobj);
e9d55f9d	98	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	99	struct w1_f23_data *data = sl->family_data;
	100	int i, min_page, max_page;
	101	#else
80895392	102	u8 wrbuf[3];
0a25e4d5	103	#endif
80895392 EP	104
	105	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	106	return 0;
	107
abd52a13	108	mutex_lock(&sl->master->mutex);
80895392	109
e9d55f9d	110	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	111
	112	min_page = (off >> W1_PAGE_BITS);
	113	max_page = (off + count - 1) >> W1_PAGE_BITS;
	114	for (i = min_page; i <= max_page; i++) {
	115	if (w1_f23_refresh_block(sl, data, i)) {
	116	count = -EIO;
	117	goto out_up;
	118	}
	119	}
	120	memcpy(buf, &data->memory[off], count);
	121
e9d55f9d	122	#else /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5	123
80895392 EP	124	/* read directly from the EEPROM */
	125	if (w1_reset_select_slave(sl)) {
	126	count = -EIO;
	127	goto out_up;
	128	}
	129
	130	wrbuf[0] = W1_F23_READ_EEPROM;
	131	wrbuf[1] = off & 0xff;
	132	wrbuf[2] = off >> 8;
	133	w1_write_block(sl->master, wrbuf, 3);
	134	w1_read_block(sl->master, buf, count);
	135
e9d55f9d	136	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5	137
80895392	138	out_up:
abd52a13	139	mutex_unlock(&sl->master->mutex);
80895392 EP	140
	141	return count;
	142	}
	143
	144	/**
	145	* Writes to the scratchpad and reads it back for verification.
0a25e4d5 EP	146	* Then copies the scratchpad to EEPROM.
0a25e4d5 EP	147	* The data must be on one page.
80895392 EP	148	* The master must be locked.
	149	*
	150	* @param sl The slave structure
	151	* @param addr Address for the write
	152	* @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
	153	* @param data The data to write
	154	* @return 0=Success -1=failure
	155	*/
	156	static int w1_f23_write(struct w1_slave sl, int addr, int len, const u8 data)
	157	{
	158	u8 wrbuf[4];
	159	u8 rdbuf[W1_PAGE_SIZE + 3];
	160	u8 es = (addr + len - 1) & 0x1f;
	161
	162	/* Write the data to the scratchpad */
	163	if (w1_reset_select_slave(sl))
	164	return -1;
	165
	166	wrbuf[0] = W1_F23_WRITE_SCRATCH;
	167	wrbuf[1] = addr & 0xff;
	168	wrbuf[2] = addr >> 8;
	169
	170	w1_write_block(sl->master, wrbuf, 3);
	171	w1_write_block(sl->master, data, len);
	172
	173	/* Read the scratchpad and verify */
	174	if (w1_reset_select_slave(sl))
	175	return -1;
	176
	177	w1_write_8(sl->master, W1_F23_READ_SCRATCH);
	178	w1_read_block(sl->master, rdbuf, len + 3);
	179
	180	/* Compare what was read against the data written */
	181	if ((rdbuf[0] != wrbuf[1]) \|\| (rdbuf[1] != wrbuf[2]) \|\|
	182	(rdbuf[2] != es) \|\| (memcmp(data, &rdbuf[3], len) != 0))
	183	return -1;
	184
	185	/* Copy the scratchpad to EEPROM */
	186	if (w1_reset_select_slave(sl))
	187	return -1;
	188
	189	wrbuf[0] = W1_F23_COPY_SCRATCH;
	190	wrbuf[3] = es;
	191	w1_write_block(sl->master, wrbuf, 4);
	192
	193	/* Sleep for 5 ms to wait for the write to complete */
	194	msleep(5);
	195
	196	/* Reset the bus to wake up the EEPROM (this may not be needed) */
	197	w1_reset_bus(sl->master);
	198
	199	return 0;
	200	}
	201
	202	static ssize_t w1_f23_write_bin(struct kobject kobj, char buf, loff_t off,
	203	size_t count)
	204	{
	205	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	206	int addr, len, idx;
	207
	208	if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
	209	return 0;
	210
e9d55f9d	211	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	212	/* can only write full blocks in cached mode */
0a25e4d5 EP	213	if ((off & W1_PAGE_MASK) \|\| (count & W1_PAGE_MASK)) {
f24ec7f6	214	dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
0a25e4d5 EP	215	(int)off, count);
	216	return -EINVAL;
	217	}
	218
	219	/* make sure the block CRCs are valid */
	220	for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
	221	if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
	222	dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
	223	return -EINVAL;
	224	}
	225	}
e9d55f9d	226	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5	227
abd52a13	228	mutex_lock(&sl->master->mutex);
80895392 EP	229
	230	/* Can only write data to one page at a time */
	231	idx = 0;
	232	while (idx < count) {
	233	addr = off + idx;
	234	len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
	235	if (len > (count - idx))
	236	len = count - idx;
	237
	238	if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
	239	count = -EIO;
	240	goto out_up;
	241	}
	242	idx += len;
	243	}
	244
	245	out_up:
abd52a13	246	mutex_unlock(&sl->master->mutex);
80895392 EP	247
	248	return count;
	249	}
	250
	251	static struct bin_attribute w1_f23_bin_attr = {
	252	.attr = {
	253	.name = "eeprom",
	254	.mode = S_IRUGO \| S_IWUSR,
80895392 EP	255	},
	256	.size = W1_EEPROM_SIZE,
	257	.read = w1_f23_read_bin,
	258	.write = w1_f23_write_bin,
	259	};
	260
	261	static int w1_f23_add_slave(struct w1_slave *sl)
	262	{
0a25e4d5	263	int err;
e9d55f9d	264	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	265	struct w1_f23_data *data;
	266
	267	data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
	268	if (!data)
	269	return -ENOMEM;
	270	memset(data, 0, sizeof(struct w1_f23_data));
	271	sl->family_data = data;
	272
e9d55f9d	273	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5 EP	274
	275	err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	276
e9d55f9d	277	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
0a25e4d5 EP	278	if (err)
0a25e4d5 EP	279	kfree(data);
e9d55f9d	280	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
0a25e4d5 EP	281
0a25e4d5 EP	282	return err;
80895392 EP	283	}
	284
	285	static void w1_f23_remove_slave(struct w1_slave *sl)
	286	{
e9d55f9d	287	#ifdef CONFIG_W1_SLAVE_DS2433_CRC
6044ec88 JJ	288	kfree(sl->family_data);
6044ec88 JJ	289	sl->family_data = NULL;
e9d55f9d	290	#endif /* CONFIG_W1_SLAVE_DS2433_CRC */
80895392 EP	291	sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
	292	}
	293
	294	static struct w1_family_ops w1_f23_fops = {
	295	.add_slave = w1_f23_add_slave,
	296	.remove_slave = w1_f23_remove_slave,
	297	};
	298
	299	static struct w1_family w1_family_23 = {
	300	.fid = W1_EEPROM_DS2433,
	301	.fops = &w1_f23_fops,
	302	};
	303
	304	static int __init w1_f23_init(void)
	305	{
	306	return w1_register_family(&w1_family_23);
	307	}
	308
	309	static void __exit w1_f23_fini(void)
	310	{
	311	w1_unregister_family(&w1_family_23);
	312	}
	313
	314	module_init(w1_f23_init);
	315	module_exit(w1_f23_fini);