w1: Constify static w1_family_ops structs

The only usage of these structs is to assign their address to the fops
field in the w1_family struct, which is a const pointer. Make them const
to allow the compiler to put them in read-only memory.

This was done with the following Coccinelle semantic patch
(http://coccinelle.lip6.fr/):

// <smpl>
@r1 disable optional_qualifier @
identifier i;
position p;
@@
static struct w1_family_ops i@p = {...};

@ok1@
identifier r1.i;
position p;
identifier s;
@@
static struct w1_family s = {
.fops=&i@p,
};

@bad1@
position p!={r1.p,ok1.p};
identifier r1.i;
@@
i@p

@depends on !bad1 disable optional_qualifier@
identifier r1.i;
@@
static
+const
struct w1_family_ops i={};
// </smpl>

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20201004193202.4044-3-rikard.falkeborn@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230

Based on 2 normalized pattern(s):

this source code is licensed under the gnu general public license
version 2 see the file copying for more details

this source code is licensed under general public license version 2
see

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

w1: Add subsystem kernel public interface

Like other subsystems we should be able to define slave devices outside
of the w1 directory. To do this we move public facing interface
definitions to include/linux/w1.h and rename the internal definition
file to w1_internal.h.

As w1_family.h and w1_int.h contained almost entirely public
driver interface definitions we simply removed these files and
moved the remaining definitions into w1_internal.h.

With this we can now start to move slave devices out of w1/slaves and
into the subsystem based on the function they implement, again like
other drivers.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

w1: Organize driver source to natural/common order

Structures and functions should be ordered such that forward declaration
use is minimized.

MODULE_* macros should immediately follow the structures and functions
upon which they act.

Remaining MODULE_* macros should be at the end of the file in
alphabetical order.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

w1: add helper macro module_w1_family

The helper macro module_w1_family can be used in module drivers that
only register a w1 driver in their module init functions. Add this
macro and use it in all applicable drivers.

Link: http://lkml.kernel.org/r/20160531204313.20979-2-afd@ti.com
Signed-off-by: Andrew F. Davis <afd@ti.com>
Acked-by: 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>

w1: slaves: w1_ds2431: 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: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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>

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>

sysfs: add struct file* to bin_attr callbacks

This allows bin_attr->read,write,mmap callbacks to check file specific data
(such as inode owner) as part of any privilege validation.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

w1: new driver. DS2431 chip

[akpm@linux-foundation.org: minor fixlets and cleanups]
Signed-off-by: Bernhard Weirich <bernhard.weirich@riedel.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>