android_kernel_motorola_sm6225/drivers/w1/slaves/w1_therm.c
David Fries e0d29c7699 W1: w1_therm consistent mutex access code cleanup
sl->master->mutex and dev->mutex refer to the same mutex variable, but be
consistent and use the same set of pointers for the lock and unlock calls.
 It is less confusing (and one less pointer dereference this way).

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: 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 11:21:50 -07:00

255 lines
5.8 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.");
/* 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.
*/
static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
static u8 bad_roms[][9] = {
{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
{}
};
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,
};
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(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;
int i, max_trying = 10;
ssize_t c = PAGE_SIZE;
mutex_lock(&dev->mutex);
memset(rom, 0, sizeof(rom));
verdict = 0;
crc = 0;
while (max_trying--) {
if (!w1_reset_select_slave(sl)) {
int count = 0;
unsigned int tm = 750;
/* 750ms strong pullup (or delay) after the convert */
if (w1_strong_pullup)
w1_next_pullup(dev, tm);
w1_write_8(dev, W1_CONVERT_TEMP);
if (!w1_strong_pullup)
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(device, "w1_read_block() "
"returned %u 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)
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, "18S20 doesn't respond to CONVERT_TEMP.\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->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);