256 lines
5.8 KiB
C
256 lines
5.8 KiB
C
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/*
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* w1_therm.c
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*
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* Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the therms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <asm/types.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/sched.h>
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include "../w1.h"
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#include "../w1_int.h"
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#include "../w1_family.h"
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
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MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
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/* Allow the strong pullup to be disabled, but default to enabled.
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* If it was disabled a parasite powered device might not get the require
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* current to do a temperature conversion. If it is enabled parasite powered
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* devices have a better chance of getting the current required.
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*/
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static int w1_strong_pullup = 1;
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module_param_named(strong_pullup, w1_strong_pullup, int, 0);
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static u8 bad_roms[][9] = {
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{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
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{}
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};
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static ssize_t w1_therm_read(struct device *device,
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struct device_attribute *attr, char *buf);
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static struct device_attribute w1_therm_attr =
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__ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL);
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static int w1_therm_add_slave(struct w1_slave *sl)
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{
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return device_create_file(&sl->dev, &w1_therm_attr);
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}
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static void w1_therm_remove_slave(struct w1_slave *sl)
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{
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device_remove_file(&sl->dev, &w1_therm_attr);
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}
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static struct w1_family_ops w1_therm_fops = {
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.add_slave = w1_therm_add_slave,
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.remove_slave = w1_therm_remove_slave,
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};
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static struct w1_family w1_therm_family_DS18S20 = {
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.fid = W1_THERM_DS18S20,
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.fops = &w1_therm_fops,
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};
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static struct w1_family w1_therm_family_DS18B20 = {
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.fid = W1_THERM_DS18B20,
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.fops = &w1_therm_fops,
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};
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static struct w1_family w1_therm_family_DS1822 = {
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.fid = W1_THERM_DS1822,
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.fops = &w1_therm_fops,
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};
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struct w1_therm_family_converter
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{
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u8 broken;
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u16 reserved;
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struct w1_family *f;
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int (*convert)(u8 rom[9]);
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};
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/* The return value is millidegrees Centigrade. */
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static inline int w1_DS18B20_convert_temp(u8 rom[9]);
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static inline int w1_DS18S20_convert_temp(u8 rom[9]);
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static struct w1_therm_family_converter w1_therm_families[] = {
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{
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.f = &w1_therm_family_DS18S20,
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.convert = w1_DS18S20_convert_temp
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},
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{
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.f = &w1_therm_family_DS1822,
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.convert = w1_DS18B20_convert_temp
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},
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{
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.f = &w1_therm_family_DS18B20,
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.convert = w1_DS18B20_convert_temp
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},
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};
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static inline int w1_DS18B20_convert_temp(u8 rom[9])
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{
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int t = ((s16)rom[1] << 8) | rom[0];
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t = t*1000/16;
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return t;
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}
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static inline int w1_DS18S20_convert_temp(u8 rom[9])
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{
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int t, h;
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if (!rom[7])
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return 0;
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if (rom[1] == 0)
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t = ((s32)rom[0] >> 1)*1000;
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else
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t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
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t -= 250;
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h = 1000*((s32)rom[7] - (s32)rom[6]);
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h /= (s32)rom[7];
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t += h;
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return t;
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}
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static inline int w1_convert_temp(u8 rom[9], u8 fid)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
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if (w1_therm_families[i].f->fid == fid)
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return w1_therm_families[i].convert(rom);
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return 0;
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}
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static int w1_therm_check_rom(u8 rom[9])
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{
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int i;
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for (i=0; i<sizeof(bad_roms)/9; ++i)
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if (!memcmp(bad_roms[i], rom, 9))
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return 1;
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return 0;
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}
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static ssize_t w1_therm_read(struct device *device,
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struct device_attribute *attr, char *buf)
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{
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struct w1_slave *sl = dev_to_w1_slave(device);
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struct w1_master *dev = sl->master;
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u8 rom[9], crc, verdict;
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int i, max_trying = 10;
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ssize_t c = PAGE_SIZE;
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mutex_lock(&dev->mutex);
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memset(rom, 0, sizeof(rom));
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verdict = 0;
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crc = 0;
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while (max_trying--) {
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if (!w1_reset_select_slave(sl)) {
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int count = 0;
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unsigned int tm = 750;
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/* 750ms strong pullup (or delay) after the convert */
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if (w1_strong_pullup)
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w1_next_pullup(dev, tm);
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w1_write_8(dev, W1_CONVERT_TEMP);
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if (!w1_strong_pullup)
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msleep(tm);
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if (!w1_reset_select_slave(sl)) {
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w1_write_8(dev, W1_READ_SCRATCHPAD);
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if ((count = w1_read_block(dev, rom, 9)) != 9) {
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dev_warn(device, "w1_read_block() "
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"returned %u instead of 9.\n",
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count);
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}
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crc = w1_calc_crc8(rom, 8);
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if (rom[8] == crc)
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verdict = 1;
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}
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}
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if (!w1_therm_check_rom(rom))
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break;
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}
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for (i = 0; i < 9; ++i)
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c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
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c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
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crc, (verdict) ? "YES" : "NO");
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if (verdict)
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memcpy(sl->rom, rom, sizeof(sl->rom));
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else
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dev_warn(device, "18S20 doesn't respond to CONVERT_TEMP.\n");
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for (i = 0; i < 9; ++i)
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c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
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c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
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w1_convert_temp(rom, sl->family->fid));
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mutex_unlock(&dev->mutex);
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return PAGE_SIZE - c;
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}
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static int __init w1_therm_init(void)
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{
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int err, i;
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for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
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err = w1_register_family(w1_therm_families[i].f);
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if (err)
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w1_therm_families[i].broken = 1;
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}
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return 0;
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}
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static void __exit w1_therm_fini(void)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
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if (!w1_therm_families[i].broken)
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w1_unregister_family(w1_therm_families[i].f);
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}
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module_init(w1_therm_init);
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module_exit(w1_therm_fini);
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