kernel-ark/drivers/w1/w1_io.c

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/*
* w1_io.c
*
* Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <asm/io.h>
#include <linux/delay.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
#include "w1.h"
#include "w1_log.h"
static int w1_delay_parm = 1;
module_param_named(delay_coef, w1_delay_parm, int, 0);
static u8 w1_crc8_table[] = {
0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
};
static void w1_delay(unsigned long tm)
{
udelay(tm * w1_delay_parm);
}
static void w1_write_bit(struct w1_master *dev, int bit);
static u8 w1_read_bit(struct w1_master *dev);
/**
* Generates a write-0 or write-1 cycle and samples the level.
*/
static u8 w1_touch_bit(struct w1_master *dev, int bit)
{
if (dev->bus_master->touch_bit)
return dev->bus_master->touch_bit(dev->bus_master->data, bit);
else if (bit)
return w1_read_bit(dev);
else {
w1_write_bit(dev, 0);
return 0;
}
}
/**
* Generates a write-0 or write-1 cycle.
* Only call if dev->bus_master->touch_bit is NULL
*/
static void w1_write_bit(struct w1_master *dev, int bit)
{
if (bit) {
dev->bus_master->write_bit(dev->bus_master->data, 0);
w1_delay(6);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(64);
} else {
dev->bus_master->write_bit(dev->bus_master->data, 0);
w1_delay(60);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(10);
}
}
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
/**
* Pre-write operation, currently only supporting strong pullups.
* Program the hardware for a strong pullup, if one has been requested and
* the hardware supports it.
*
* @param dev the master device
*/
static void w1_pre_write(struct w1_master *dev)
{
if (dev->pullup_duration &&
dev->enable_pullup && dev->bus_master->set_pullup) {
dev->bus_master->set_pullup(dev->bus_master->data,
dev->pullup_duration);
}
}
/**
* Post-write operation, currently only supporting strong pullups.
* If a strong pullup was requested, clear it if the hardware supports
* them, or execute the delay otherwise, in either case clear the request.
*
* @param dev the master device
*/
static void w1_post_write(struct w1_master *dev)
{
if (dev->pullup_duration) {
if (dev->enable_pullup && dev->bus_master->set_pullup)
dev->bus_master->set_pullup(dev->bus_master->data, 0);
else
msleep(dev->pullup_duration);
dev->pullup_duration = 0;
}
}
/**
* Writes 8 bits.
*
* @param dev the master device
* @param byte the byte to write
*/
void w1_write_8(struct w1_master *dev, u8 byte)
{
int i;
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
if (dev->bus_master->write_byte) {
w1_pre_write(dev);
dev->bus_master->write_byte(dev->bus_master->data, byte);
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
}
else
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
for (i = 0; i < 8; ++i) {
if (i == 7)
w1_pre_write(dev);
w1_touch_bit(dev, (byte >> i) & 0x1);
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
}
w1_post_write(dev);
}
EXPORT_SYMBOL_GPL(w1_write_8);
/**
* Generates a write-1 cycle and samples the level.
* Only call if dev->bus_master->touch_bit is NULL
*/
static u8 w1_read_bit(struct w1_master *dev)
{
int result;
dev->bus_master->write_bit(dev->bus_master->data, 0);
w1_delay(6);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(9);
result = dev->bus_master->read_bit(dev->bus_master->data);
w1_delay(55);
return result & 0x1;
}
/**
* Does a triplet - used for searching ROM addresses.
* Return bits:
* bit 0 = id_bit
* bit 1 = comp_bit
* bit 2 = dir_taken
* If both bits 0 & 1 are set, the search should be restarted.
*
* @param dev the master device
* @param bdir the bit to write if both id_bit and comp_bit are 0
* @return bit fields - see above
*/
u8 w1_triplet(struct w1_master *dev, int bdir)
{
if (dev->bus_master->triplet)
return dev->bus_master->triplet(dev->bus_master->data, bdir);
else {
u8 id_bit = w1_touch_bit(dev, 1);
u8 comp_bit = w1_touch_bit(dev, 1);
u8 retval;
if (id_bit && comp_bit)
return 0x03; /* error */
if (!id_bit && !comp_bit) {
/* Both bits are valid, take the direction given */
retval = bdir ? 0x04 : 0;
} else {
/* Only one bit is valid, take that direction */
bdir = id_bit;
retval = id_bit ? 0x05 : 0x02;
}
if (dev->bus_master->touch_bit)
w1_touch_bit(dev, bdir);
else
w1_write_bit(dev, bdir);
return retval;
}
}
/**
* Reads 8 bits.
*
* @param dev the master device
* @return the byte read
*/
u8 w1_read_8(struct w1_master *dev)
{
int i;
u8 res = 0;
if (dev->bus_master->read_byte)
res = dev->bus_master->read_byte(dev->bus_master->data);
else
for (i = 0; i < 8; ++i)
res |= (w1_touch_bit(dev,1) << i);
return res;
}
EXPORT_SYMBOL_GPL(w1_read_8);
/**
* Writes a series of bytes.
*
* @param dev the master device
* @param buf pointer to the data to write
* @param len the number of bytes to write
*/
void w1_write_block(struct w1_master *dev, const u8 *buf, int len)
{
int i;
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
if (dev->bus_master->write_block) {
w1_pre_write(dev);
dev->bus_master->write_block(dev->bus_master->data, buf, len);
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
}
else
for (i = 0; i < len; ++i)
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
w1_write_8(dev, buf[i]); /* calls w1_pre_write */
w1_post_write(dev);
}
EXPORT_SYMBOL_GPL(w1_write_block);
/**
* Touches a series of bytes.
*
* @param dev the master device
* @param buf pointer to the data to write
* @param len the number of bytes to write
*/
void w1_touch_block(struct w1_master *dev, u8 *buf, int len)
{
int i, j;
u8 tmp;
for (i = 0; i < len; ++i) {
tmp = 0;
for (j = 0; j < 8; ++j) {
if (j == 7)
w1_pre_write(dev);
tmp |= w1_touch_bit(dev, (buf[i] >> j) & 0x1) << j;
}
buf[i] = tmp;
}
}
EXPORT_SYMBOL_GPL(w1_touch_block);
/**
* Reads a series of bytes.
*
* @param dev the master device
* @param buf pointer to the buffer to fill
* @param len the number of bytes to read
* @return the number of bytes read
*/
u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
{
int i;
u8 ret;
if (dev->bus_master->read_block)
ret = dev->bus_master->read_block(dev->bus_master->data, buf, len);
else {
for (i = 0; i < len; ++i)
buf[i] = w1_read_8(dev);
ret = len;
}
return ret;
}
EXPORT_SYMBOL_GPL(w1_read_block);
/**
* Issues a reset bus sequence.
*
* @param dev The bus master pointer
* @return 0=Device present, 1=No device present or error
*/
int w1_reset_bus(struct w1_master *dev)
{
int result;
if (dev->bus_master->reset_bus)
result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
else {
dev->bus_master->write_bit(dev->bus_master->data, 0);
/* minimum 480, max ? us
* be nice and sleep, except 18b20 spec lists 960us maximum,
* so until we can sleep with microsecond accuracy, spin.
* Feel free to come up with some other way to give up the
* cpu for such a short amount of time AND get it back in
* the maximum amount of time.
*/
w1_delay(480);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(70);
result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
/* minmum 70 (above) + 410 = 480 us
* There aren't any timing requirements between a reset and
* the following transactions. Sleeping is safe here.
*/
/* w1_delay(410); min required time */
msleep(1);
}
return result;
}
EXPORT_SYMBOL_GPL(w1_reset_bus);
u8 w1_calc_crc8(u8 * data, int len)
{
u8 crc = 0;
while (len--)
crc = w1_crc8_table[crc ^ *data++];
return crc;
}
EXPORT_SYMBOL_GPL(w1_calc_crc8);
void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
{
dev->attempts++;
if (dev->bus_master->search)
dev->bus_master->search(dev->bus_master->data, dev,
search_type, cb);
else
w1_search(dev, search_type, cb);
}
/**
* Resets the bus and then selects the slave by sending either a skip rom
* or a rom match.
* The w1 master lock must be held.
*
* @param sl the slave to select
* @return 0=success, anything else=error
*/
int w1_reset_select_slave(struct w1_slave *sl)
{
if (w1_reset_bus(sl->master))
return -1;
if (sl->master->slave_count == 1)
w1_write_8(sl->master, W1_SKIP_ROM);
else {
u8 match[9] = {W1_MATCH_ROM, };
u64 rn = le64_to_cpu(*((u64*)&sl->reg_num));
memcpy(&match[1], &rn, 8);
w1_write_block(sl->master, match, 9);
}
return 0;
}
EXPORT_SYMBOL_GPL(w1_reset_select_slave);
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:42 +00:00
/**
* Put out a strong pull-up of the specified duration after the next write
* operation. Not all hardware supports strong pullups. Hardware that
* doesn't support strong pullups will sleep for the given time after the
* write operation without a strong pullup. This is a one shot request for
* the next write, specifying zero will clear a previous request.
* The w1 master lock must be held.
*
* @param delay time in milliseconds
* @return 0=success, anything else=error
*/
void w1_next_pullup(struct w1_master *dev, int delay)
{
dev->pullup_duration = delay;
}
EXPORT_SYMBOL_GPL(w1_next_pullup);