Commit Graph

21 Commits

Author SHA1 Message Date
Raphael Assenat f3261dfb55 1-Wire: Add support for the maxim ds1825 temperature sensor
This patch adds support for maxim ds1825 based 1-wire temperature sensors.

Signed-off-by: Raphael Assenat <raph@8d.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-16 12:33:59 -07:00
NeilBrown b02f8bede2 W1: split master mutex to avoid deadlocks.
The 'mutex' in struct w1_master is use for two very different
purposes.

Firstly it protects various data structures such as the list of all
slaves.

Secondly it protects the w1 buss against concurrent accesses.

This can lead to deadlocks when the ->probe code called while adding a
slave needs to talk on the bus, as is the case for power_supply
devices.
ds2780 and ds2781 drivers contain a work around to track which
process hold the lock simply to avoid this deadlock.  bq27000 doesn't
have that work around and so deadlocks.

There are other possible deadlocks involving sysfs.
When removing a device the sysfs s_active lock is held, so the lock
that protects the slave list must take precedence over s_active.
However when access power_supply attributes via sysfs, the s_active
lock must take precedence over the lock that protects accesses to
the bus.

So to avoid deadlocks between w1 slaves and sysfs, these must be
two separate locks.  Making them separate means that the work around
in ds2780 and ds2781 can be removed.

So this patch:
 - adds a new mutex: "bus_mutex" which serialises access to the bus.
 - takes in mutex in w1_search and ds1wm_search while they access
   the bus for searching.  The mutex is dropped before calling the
   callback which adds the slave.
 - changes all slaves to use bus_mutex instead of mutex to
   protect access to the bus
 - removes w1_ds2790_io_nolock and w1_ds2781_io_nolock, and the
   related code from drivers/power/ds278[01]_battery.c which
   calls them.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-13 16:38:40 -07:00
Maciej Szmigiero 377195c438 W1: w1_therm: release the bus during conversion on externally powered devices
w1_therm devices can either be bus powered or externally powered.

When device is bus powered during temperature conversion the bus
have to be left high to provide necessary power. Some masters also allow
strong power-up to be enabled in this case.
Naturally, no communication over bus can occur during that time.

However, if device has external power then there is no such restriction,
and host can talk to other devices during temperature conversion.

There is command which allows us to check how device is powered,
this patch uses it to release the bus on externally w1_therm powered devices
during temperature conversion.

Also, this changes uninterruptible sleeps there into interruptible ones to
avoid long uninterruptible sleep if w1 subsystem happens to grab bus for
scan during w1_therm_read().

Signed-off-by: Maciej Szmigiero <mhej@o2.pl>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-17 11:47:56 -08:00
Evgeniy Polyakov a801876638 MAINTAINERS: Evgeniy has moved
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-25 16:25:33 -07:00
Christian Glindkamp f7b1371eb6 drivers/w1/slaves/w1_therm.c: add support for DS28EA00
Signed-off-by: Christian Glindkamp <christian.glindkamp@taskit.de>
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>
2011-07-26 16:49:45 -07:00
Ian Dall 9a6a1ecd9e w1: w1 temp: fix negative termperature calculation
Fix regression caused by commit 507e2fbaaa
("w1: w1 temp calculation overflow fix") whereby negative temperatures for
the DS18B20 are not converted properly.

When the temperature exceeds 32767 milli-degrees the temperature overflows
to -32768 millidegrees.  These are both well within the -55 - +125 degree
range for the sensor.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=12646

Signed-of-by: Ian Dall <ian@beware.dropbear.id.au>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Tested-by: Karsten Elfenbein <kelfe@gmx.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-24 11:31:25 -07:00
Ian Dall 507e2fbaaa w1: w1 temp calculation overflow fix
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12646

When the temperature exceeds 32767 milli-degrees the temperature overflows
to -32768 millidegrees.  These are bothe well within the -55 - +125 degree
range for the sensor.

Fix overflow in left-shift of a u8.

Signed-off-by: Ian Dall <ian@beware.dropbear.id.au>
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-11 14:25:37 -08:00
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
David Fries 347ba8a588 W1: w1_therm fix user buffer overflow and cat
Fixed data reading bug by replacing binary attribute with device one.

Switching the sysfs read from bin_attribute to device_attribute.  The data
is far under PAGE_SIZE so the binary interface isn't required.  As the
device_attribute interface will make one call to w1_therm_read per file
open and buffer, the result is, the following problems go away.

buffer overflow:
	Execute a short read on w1_slave and w1_therm_read_bin would still
	return the full string size worth of data clobbering the user space
	buffer when it returned.  Switching to device_attribute avoids the
	buffer overflow problems.  With the snprintf formatted output dealing
	with short reads without doing a conversion per read would have
	been difficult.
bad behavior:
	`cat w1_slave` would cause two temperature conversions to take place.
	Previously the code assumed W1_SLAVE_DATA_SIZE would be returned with
	each read.  It would not return 0 unless the offset was less
	than W1_SLAVE_DATA_SIZE.  The result was the first read did a
	temperature conversion, filled the buffer and returned, the
	offset in the second read would be less than
	W1_SLAVE_DATA_SIZE and also fill the buffer and return, the
	third read would finnally have a big enough offset to return 0
	and cause cat to stop.  Now w1_therm_read will be called at
	most once per open.

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
David Fries 6cd159744e W1: feature, w1_therm.c use strong pullup and documentation
Added strong pullup to thermal sensor driver and general documentation on
the sensor.

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 11:21:49 -07:00
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
David Fries 80c002ddd2 W1: w1_therm.c is flagging 0C etc as invalid
The extra rom[0] check is flagging valid temperatures as invalid when
there is already a CRC data transmission check.

w1_therm_read_bin()
	if (rom[8] == crc && rom[0])
		verdict = 1;

Requiring rom[0] to be non-zero will flag as invalid temperature
conversions when the low byte is zero, specifically the temperatures 0C,
16C, 32C, 48C, -16C, -32C, and -48C.

The CRC check is produced on the device for the previous 8 bytes and is
required to ensure the data integrity in transmission.  I don't see why the
extra check for rom[0] being non-zero is in there.  Evgeniy Polyakov didn't
know either.  Just for a check I unplugged the sensor, executed a
temperature conversion, and read the results.  The read was all ff's, which
also failed the CRC, so it doesn't need to protect against a disconnected
sensor.

I have more extensive patches in the work, but these two trivial ones will
do for today.  I would like to hear from people who use the ds2490 USB to
one wire dongle.  1 if you would be willing to test the patches as I
currently only have the one sensor on a short parisite powered wire, 2 if
there is any cheap sources for the ds2490.

Signed-off-by: David Fries <david@fries.net>
Acked-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>
2008-01-22 09:17:48 -08:00
David Fries 941ed3b530 W1: w1_therm.c ds18b20 decode freezing temperatures correctly
Correct the decoding of negative C temperatures.  The code did a binary OR
of two bytes to make a 16 bit value, but assignd it to an integer.  This
caused the value to not be sign extended and to loose that it was a
negative number in the assignment.

Before the patch (in my freezer),
	w1_slave
	ed fe 4b 46 7f ff 03 10 e4 : crc=e4 YES
	ed fe 4b 46 7f ff 03 10 e4 t=4078
With the patch,
	e3 fe 4b 46 7f ff 0d 10 81 : crc=81 YES
	e3 fe 4b 46 7f ff 0d 10 81 t=-17

Signed-off-by: David Fries <david@fries.net>
Acked-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>
2008-01-22 09:17:48 -08:00
Zhang Rui 91a6902958 sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes
Well, first of all, I don't want to change so many files either.

What I do:
Adding a new parameter "struct bin_attribute *" in the
.read/.write methods for the sysfs binary attributes.

In fact, only the four lines change in fs/sysfs/bin.c and
include/linux/sysfs.h do the real work.
But I have to update all the files that use binary attributes
to make them compatible with the new .read and .write methods.
I'm not sure if I missed any. :(

Why I do this:
For a sysfs attribute, we can get a pointer pointing to the
struct attribute in the .show/.store method,
while we can't do this for the binary attributes.
I don't know why this is different, but this does make it not
so handy to use the binary attributes as the regular ones.
So I think this patch is reasonable. :)

Who benefits from it:
The patch that exposes ACPI tables in sysfs
requires such an improvement.
All the table binary attributes share the same .read method.
Parameter "struct bin_attribute *" is used to get
the table signature and instance number which are used to
distinguish different ACPI table binary attributes.

Without this parameter, we need to offer different .read methods
for different ACPI table binary attributes.
This is impossible as there are various ACPI tables on different
platforms, and we don't know what they are until they are loaded.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:09 -07:00
Tejun Heo 7b595756ec sysfs: kill unnecessary attribute->owner
sysfs is now completely out of driver/module lifetime game.  After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners.  Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.

This patch kills now unnecessary attribute->owner.  Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.

For more info regarding lifetime rule cleanup, please read the
following message.

  http://article.gmane.org/gmane.linux.kernel/510293

(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:06 -07:00
Evgeniy Polyakov 33e44b1588 w1_therm_read_bin: don't call flush_signals()
This can disrupt userspace signal management.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-28 11:38:19 -07:00
Ahmed S. Darwish 9d0094de6d [PATCH] w1: Use ARRAY_SIZE macro when appropriate
A patch to use ARRAY_SIZE macro already defined in kernel.h

Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Acked-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>
2007-02-12 09:48:28 -08:00
Al Viro f6a570333e [PATCH] severing module.h->sched.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-12-04 02:00:22 -05:00
Evgeniy Polyakov abd52a1320 [PATCH] w1: Use mutexes instead of semaphores.
Use mutexes instead of semaphores.
Patch tested on x86_64 and i386 with test bus master driver.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-22 11:22:50 -07:00
Evgeniy Polyakov 12003375ac [PATCH] w1: Userspace communication protocol over connector.
There are three types of messages between w1 core and userspace:
1. Events. They are generated each time new master or slave device found
	either due to automatic or requested search.
2. Userspace commands. Includes read/write and search/alarm search comamnds.
3. Replies to userspace commands.

From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-22 11:22:50 -07:00
Evgeniy Polyakov bd529cfb40 [PATCH] W1: Move w1 bus master code into 'w1/masters' and move w1 slave code into 'w1/slaves'
Signed-off-by: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 17:28:11 -08:00