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/*
* w1_therm.c
*
* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the therms 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/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
/* Allow the strong pullup to be disabled, but default to enabled.
* If it was disabled a parasite powered device might not get the require
* current to do a temperature conversion. If it is enabled parasite powered
* devices have a better chance of getting the current required.
* In case the parasite power-detection is not working (seems to be the case
* for some DS18S20) the strong pullup can also be forced, regardless of the
* power state of the devices.
*
* Summary of options:
* - strong_pullup = 0 Disable strong pullup completely
* - strong_pullup = 1 Enable automatic strong pullup detection
* - strong_pullup = 2 Force strong pullup
*/
static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
static ssize_t w1_therm_read(struct device *device,
struct device_attribute *attr, char *buf);
static struct device_attribute w1_therm_attr =
__ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL);
static int w1_therm_add_slave(struct w1_slave *sl)
{
return device_create_file(&sl->dev, &w1_therm_attr);
}
static void w1_therm_remove_slave(struct w1_slave *sl)
{
device_remove_file(&sl->dev, &w1_therm_attr);
}
static struct w1_family_ops w1_therm_fops = {
.add_slave = w1_therm_add_slave,
.remove_slave = w1_therm_remove_slave,
};
static struct w1_family w1_therm_family_DS18S20 = {
.fid = W1_THERM_DS18S20,
.fops = &w1_therm_fops,
};
static struct w1_family w1_therm_family_DS18B20 = {
.fid = W1_THERM_DS18B20,
.fops = &w1_therm_fops,
};
static struct w1_family w1_therm_family_DS1822 = {
.fid = W1_THERM_DS1822,
.fops = &w1_therm_fops,
};
static struct w1_family w1_therm_family_DS28EA00 = {
.fid = W1_THERM_DS28EA00,
.fops = &w1_therm_fops,
};
static struct w1_family w1_therm_family_DS1825 = {
.fid = W1_THERM_DS1825,
.fops = &w1_therm_fops,
};
struct w1_therm_family_converter
{
u8 broken;
u16 reserved;
struct w1_family *f;
int (*convert)(u8 rom[9]);
};
/* The return value is millidegrees Centigrade. */
static inline int w1_DS18B20_convert_temp(u8 rom[9]);
static inline int w1_DS18S20_convert_temp(u8 rom[9]);
static struct w1_therm_family_converter w1_therm_families[] = {
{
.f = &w1_therm_family_DS18S20,
.convert = w1_DS18S20_convert_temp
},
{
.f = &w1_therm_family_DS1822,
.convert = w1_DS18B20_convert_temp
},
{
.f = &w1_therm_family_DS18B20,
.convert = w1_DS18B20_convert_temp
},
{
.f = &w1_therm_family_DS28EA00,
.convert = w1_DS18B20_convert_temp
},
{
.f = &w1_therm_family_DS1825,
.convert = w1_DS18B20_convert_temp
}
};
static inline int w1_DS18B20_convert_temp(u8 rom[9])
{
s16 t = le16_to_cpup((__le16 *)rom);
return t*1000/16;
}
static inline int w1_DS18S20_convert_temp(u8 rom[9])
{
int t, h;
if (!rom[7])
return 0;
if (rom[1] == 0)
t = ((s32)rom[0] >> 1)*1000;
else
t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
t -= 250;
h = 1000*((s32)rom[7] - (s32)rom[6]);
h /= (s32)rom[7];
t += h;
return t;
}
static inline int w1_convert_temp(u8 rom[9], u8 fid)
{
int i;
for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
if (w1_therm_families[i].f->fid == fid)
return w1_therm_families[i].convert(rom);
return 0;
}
static ssize_t w1_therm_read(struct device *device,
struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
u8 rom[9], crc, verdict, external_power;
int i, max_trying = 10;
ssize_t c = PAGE_SIZE;
i = mutex_lock_interruptible(&dev->bus_mutex);
if (i != 0)
return i;
memset(rom, 0, sizeof(rom));
while (max_trying--) {
verdict = 0;
crc = 0;
if (!w1_reset_select_slave(sl)) {
int count = 0;
unsigned int tm = 750;
unsigned long sleep_rem;
w1_write_8(dev, W1_READ_PSUPPLY);
external_power = w1_read_8(dev);
if (w1_reset_select_slave(sl))
continue;
/* 750ms strong pullup (or delay) after the convert */
if (w1_strong_pullup == 2 ||
(!external_power && w1_strong_pullup))
w1_next_pullup(dev, tm);
w1_write_8(dev, W1_CONVERT_TEMP);
if (external_power) {
mutex_unlock(&dev->bus_mutex);
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0)
return -EINTR;
i = mutex_lock_interruptible(&dev->bus_mutex);
if (i != 0)
return i;
} else if (!w1_strong_pullup) {
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0) {
mutex_unlock(&dev->bus_mutex);
return -EINTR;
}
}
if (!w1_reset_select_slave(sl)) {
w1_write_8(dev, W1_READ_SCRATCHPAD);
if ((count = w1_read_block(dev, rom, 9)) != 9) {
dev_warn(device, "w1_read_block() "
"returned %u instead of 9.\n",
count);
}
crc = w1_calc_crc8(rom, 8);
if (rom[8] == crc)
verdict = 1;
}
}
if (verdict)
break;
}
for (i = 0; i < 9; ++i)
c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
crc, (verdict) ? "YES" : "NO");
if (verdict)
memcpy(sl->rom, rom, sizeof(sl->rom));
else
dev_warn(device, "Read failed CRC check\n");
for (i = 0; i < 9; ++i)
c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
w1_convert_temp(rom, sl->family->fid));
mutex_unlock(&dev->bus_mutex);
return PAGE_SIZE - c;
}
static int __init w1_therm_init(void)
{
int err, i;
for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
err = w1_register_family(w1_therm_families[i].f);
if (err)
w1_therm_families[i].broken = 1;
}
return 0;
}
static void __exit w1_therm_fini(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
if (!w1_therm_families[i].broken)
w1_unregister_family(w1_therm_families[i].f);
}
module_init(w1_therm_init);
module_exit(w1_therm_fini);
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