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310 lines
7.3 KiB
310 lines
7.3 KiB
/*
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* w1_therm.c
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*
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* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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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/slab.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 <zbr@ioremap.net>");
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MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
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MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
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MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
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MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
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MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
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MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
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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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* In case the parasite power-detection is not working (seems to be the case
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* for some DS18S20) the strong pullup can also be forced, regardless of the
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* power state of the devices.
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*
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* Summary of options:
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* - strong_pullup = 0 Disable strong pullup completely
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* - strong_pullup = 1 Enable automatic strong pullup detection
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* - strong_pullup = 2 Force strong pullup
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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 int w1_therm_add_slave(struct w1_slave *sl)
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{
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sl->family_data = kzalloc(9, GFP_KERNEL);
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if (!sl->family_data)
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return -ENOMEM;
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return 0;
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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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kfree(sl->family_data);
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sl->family_data = NULL;
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}
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static ssize_t w1_slave_show(struct device *device,
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struct device_attribute *attr, char *buf);
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static DEVICE_ATTR_RO(w1_slave);
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static struct attribute *w1_therm_attrs[] = {
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&dev_attr_w1_slave.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(w1_therm);
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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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.groups = w1_therm_groups,
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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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static struct w1_family w1_therm_family_DS28EA00 = {
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.fid = W1_THERM_DS28EA00,
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.fops = &w1_therm_fops,
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};
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static struct w1_family w1_therm_family_DS1825 = {
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.fid = W1_THERM_DS1825,
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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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.f = &w1_therm_family_DS28EA00,
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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_DS1825,
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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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s16 t = le16_to_cpup((__le16 *)rom);
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return t*1000/16;
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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 ssize_t w1_slave_show(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, external_power;
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int i, max_trying = 10;
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ssize_t c = PAGE_SIZE;
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i = mutex_lock_interruptible(&dev->bus_mutex);
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if (i != 0)
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return i;
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memset(rom, 0, sizeof(rom));
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while (max_trying--) {
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verdict = 0;
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crc = 0;
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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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unsigned long sleep_rem;
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w1_write_8(dev, W1_READ_PSUPPLY);
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external_power = w1_read_8(dev);
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if (w1_reset_select_slave(sl))
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continue;
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/* 750ms strong pullup (or delay) after the convert */
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if (w1_strong_pullup == 2 ||
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(!external_power && 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 (external_power) {
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mutex_unlock(&dev->bus_mutex);
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sleep_rem = msleep_interruptible(tm);
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if (sleep_rem != 0)
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return -EINTR;
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i = mutex_lock_interruptible(&dev->bus_mutex);
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if (i != 0)
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return i;
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} else if (!w1_strong_pullup) {
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sleep_rem = msleep_interruptible(tm);
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if (sleep_rem != 0) {
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mutex_unlock(&dev->bus_mutex);
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return -EINTR;
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}
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}
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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 (verdict)
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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->family_data, rom, sizeof(rom));
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else
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dev_warn(device, "Read failed CRC check\n");
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for (i = 0; i < 9; ++i)
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c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
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((u8 *)sl->family_data)[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->bus_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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