linux/drivers/w1/slaves/w1_therm.c
David Fries 7129b126cc W1: w1_therm.c standardize units to millidegrees C
Standardize the temperature units to millidegrees C for the two sensor
conversion routines.  Previously the routines were,

w1_DS18B20_convert_temp degrees C
w1_DS18S20_convert_temp millidegrees C

Unfortunately this will break any program using the ds18b20 value as it
will now be 1000 times bigger.  Fortunately there can't be that many users
out there, or some of these bugs will have been fixed by now, such as the
negative C error (see previous patch) that makes me think the ds18b20 is
the better choice to change because of the current bugs.

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>
2008-02-06 10:41:10 -08:00

260 lines
5.6 KiB
C

/*
* w1_therm.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 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 <johnpol@2ka.mipt.ru>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
static u8 bad_roms[][9] = {
{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
{}
};
static ssize_t w1_therm_read_bin(struct kobject *, struct bin_attribute *,
char *, loff_t, size_t);
static struct bin_attribute w1_therm_bin_attr = {
.attr = {
.name = "w1_slave",
.mode = S_IRUGO,
},
.size = W1_SLAVE_DATA_SIZE,
.read = w1_therm_read_bin,
};
static int w1_therm_add_slave(struct w1_slave *sl)
{
return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
}
static void w1_therm_remove_slave(struct w1_slave *sl)
{
sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_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,
};
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
},
};
static inline int w1_DS18B20_convert_temp(u8 rom[9])
{
s16 t = (rom[1] << 8) | rom[0];
t = t*1000/16;
return t;
}
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 int w1_therm_check_rom(u8 rom[9])
{
int i;
for (i=0; i<sizeof(bad_roms)/9; ++i)
if (!memcmp(bad_roms[i], rom, 9))
return 1;
return 0;
}
static ssize_t w1_therm_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);
struct w1_master *dev = sl->master;
u8 rom[9], crc, verdict;
int i, max_trying = 10;
mutex_lock(&sl->master->mutex);
if (off > W1_SLAVE_DATA_SIZE) {
count = 0;
goto out;
}
if (off + count > W1_SLAVE_DATA_SIZE) {
count = 0;
goto out;
}
memset(buf, 0, count);
memset(rom, 0, sizeof(rom));
count = 0;
verdict = 0;
crc = 0;
while (max_trying--) {
if (!w1_reset_select_slave(sl)) {
int count = 0;
unsigned int tm = 750;
w1_write_8(dev, W1_CONVERT_TEMP);
msleep(tm);
if (!w1_reset_select_slave(sl)) {
w1_write_8(dev, W1_READ_SCRATCHPAD);
if ((count = w1_read_block(dev, rom, 9)) != 9) {
dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
}
crc = w1_calc_crc8(rom, 8);
if (rom[8] == crc)
verdict = 1;
}
}
if (!w1_therm_check_rom(rom))
break;
}
for (i = 0; i < 9; ++i)
count += sprintf(buf + count, "%02x ", rom[i]);
count += sprintf(buf + count, ": crc=%02x %s\n",
crc, (verdict) ? "YES" : "NO");
if (verdict)
memcpy(sl->rom, rom, sizeof(sl->rom));
else
dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
for (i = 0; i < 9; ++i)
count += sprintf(buf + count, "%02x ", sl->rom[i]);
count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
out:
mutex_unlock(&dev->mutex);
return count;
}
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);