Commit Graph

9 Commits

Author SHA1 Message Date
Greg Kroah-Hartman 32ea4175ae w1: slaves: w1_ds2408: convert to use w1_family_ops.groups
This moves the sysfs file creation/removal to the w1 core by using the
.groups field, saving code in the slave driver.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-22 11:05:42 -07:00
Jean-Francois Dagenais d5528773e6 drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode
Power-up timing

The DS2408 is sensitive to the power-on slew rate and can inadvertently
power up with a test mode feature enabled.  When this occurs, the P0 port
does not respond to the Channel Access Write command.  For most reliable
operation, it is recommended to disable the test mode after every power-on
reset using the Disable Test Mode sequence shown below.  The 64-bit ROM
code must be transmitted in the same bit sequence as with the Match ROM
command, i.e., least significant bit first.  This precaution is
recommended in parasite power mode (VCC pin connected to GND) as well as
with VCC power.

Disable Test Mode:
RST,PD,96h,<64-bit DS2408 ROM Code>,3Ch,RST,PD

[akpm@linux-foundation.org: don't use kerenldoc token to introduce a non-kerneldoc comment, tweak whitespace]
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:08:06 -07:00
Alexander Stein 8d7bda5188 w1: add family based automatic module loading
This patch allows the 1-wire bus to autoload the corresponding module
for each slave being attached.
This works similar to bluetooth protocols.

Signed-off-by: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-03 14:09:14 -07:00
Jean-Francois Dagenais 1116575d91 w1: ds2408: use ARRAY_SIZE instead of hard-coded number
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-15 12:15:02 -07:00
Jean-Francois Dagenais aceca28544 w1: ds2408: make value read-back check a Kconfig option
De-activating this reading back will effectively half the time required
for a write to the output register.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-15 12:15:02 -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
H Hartley Sweeten 4ae68e7345 w1: w1_ds2408.c: quite sparse noise about using plaing integer as NULL pointer
NULL not 0 should be used with pointers. Just remove the offending
lines since they will default to NULL anyway.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-04 16:25:30 -07:00
Dan Carpenter 5829944925 w1: fix for loop in w1_f29_remove_slave()
The for loop was looking for i <= 0 instead of i >= 0 so this function
never did anything.  Also we started with i = NB_SYSFS_BIN_FILES instead
of "NB_SYSFS_BIN_FILES - 1" which is an off by one bug.

Reported-by: Bojan Prtvar <prtvar.b@gmail.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jean-Franois Dagenais <dagenaisj@sonatest.com>
Cc: 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
Jean-François Dagenais 89610274bd w1: add 1-wire (w1) DS2408 8-Channel Addressable Switch support
This DS2408 w1 slave driver is not complete for all the features of the
chip, but its sufficient if you use it as a simple IO expander.

[randy.dunlap@oracle.com: fix w1_ds2408.c printk formats]
Signed-off-by: Jean-François Dagenais <dagenaisj@sonatest.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Cc: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 17:12:38 -07:00