The hwmon core registers the hwmon device before adding sensors to the
thermal core. If that fails, the hwmon device is released and an error
is returned to the caller. From the code flow, it appears to be necessary
to free struct hwmon_device *, allocated with kzalloc(), in that
situation. This is incorrect, since the data structure will be freed
automatically in hwmon_dev_release() when device_unregister() is called.
This used to result in a double free, which was found and fixed with
commit 74e35127 ("hwmon: (core) Fix double-free in
__hwmon_device_register()"). This is, however, not obvious; any reader
may erroneously conclude that the data structure is not freed.

Add comment explaining why kfree() is not necessary in this situation.
Reported-by: NEduardo Valentin <eduval@amazon.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Drivers may register to hwmon and request for also registering
with the thermal subsystem (HWMON_C_REGISTER_TZ). However,
some of these driver, e.g. marvell phy, may be probed from
Device Tree or being dynamically allocated, and in the later
case, it will not have a dev->of_node entry.

Registering with hwmon without the dev->of_node may result in
different outcomes depending on the device tree, which may
be a bit misleading. If the device tree blob has no 'thermal-zones'
node, the *hwmon_device_register*() family functions are going
to gracefully succeed, because of-thermal,
*thermal_zone_of_sensor_register() return -ENODEV in this case,
and the hwmon error path handles this error code as success to
cover for the case where CONFIG_THERMAL_OF is not set.
However, if the device tree blob has the 'thermal-zones'
entry, the *hwmon_device_register*() will always fail on callers
with no dev->of_node, propagating -EINVAL.

If dev->of_node is not present, calling of-thermal does not
make sense. For this reason, this patch checks first if the
device has a of_node before going over the process of registering
with the thermal subsystem of-thermal interface. And in this case,
when a caller of *hwmon_device_register*() with HWMON_C_REGISTER_TZ
and no dev->of_node will still register with hwmon, but not with
the thermal subsystem. If all the hwmon part bits are in place,
the registration will succeed.

Fixes: d560168b ("hwmon: (core) New hwmon registration API")
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <eduval@amazon.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Reviewed-by: NArmijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As the thermal framework does not longer compile as a module, we can
simplify this condition below:

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) && \
       (!defined(CONFIG_THERMAL_HWMON) || \
        !(defined(MODULE) && IS_MODULE(CONFIG_THERMAL)))

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) && \
       (!defined(CONFIG_THERMAL_HWMON) || \
        !(defined(MODULE) && 0))

=> (whatever && 0) = 0

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) && \
       (!defined(CONFIG_THERMAL_HWMON) || !(0))

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) && \
       (!defined(CONFIG_THERMAL_HWMON) || 1)

=> (whatever || 1) = 1

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) && \
       (1)

=> (whatever && 1) = whatever

 if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF)

CONFIG_THERMAL can not be a module anymore, then:

 if defined(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF)

And CONFIG_THERMAL_OF already depends on CONFIG_THERMAL, so:

 if defined(CONFIG_THERMAL_OF)

Thus,

 ifdef CONFIG_THERMAL_OF
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>

Add support for the new samples attributes to the hwmon core.

Cc: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>
Acked-by: NNicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Replace S_<PERMS> with octal values.

The conversion was done automatically with coccinelle. The semantic patches
and the scripts used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches/hwmon/.

This patch does not introduce functional changes. It was verified by
compiling the old and new files and comparing text and data sizes.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

struct attribute::name which this local variable name is eventually
assigned to is "const char*", and so is the template parameter. We might
as well preserve the constness all the way through.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Fix double-free that happens when thermal zone setup fails, see KASAN log
below.

==================================================================
BUG: KASAN: double-free or invalid-free in __hwmon_device_register+0x5dc/0xa7c

CPU: 0 PID: 132 Comm: kworker/0:2 Tainted: G    B             4.19.0-rc8-next-20181016-00042-gb52cd80401e9-dirty #41
Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
Backtrace:
[<c0110540>] (dump_backtrace) from [<c0110944>] (show_stack+0x20/0x24)
[<c0110924>] (show_stack) from [<c105cb08>] (dump_stack+0x9c/0xb0)
[<c105ca6c>] (dump_stack) from [<c02fdaec>] (print_address_description+0x68/0x250)
[<c02fda84>] (print_address_description) from [<c02fd4ac>] (kasan_report_invalid_free+0x68/0x88)
[<c02fd444>] (kasan_report_invalid_free) from [<c02fc85c>] (__kasan_slab_free+0x1f4/0x200)
[<c02fc668>] (__kasan_slab_free) from [<c02fd0c0>] (kasan_slab_free+0x14/0x18)
[<c02fd0ac>] (kasan_slab_free) from [<c02f9c6c>] (kfree+0x90/0x294)
[<c02f9bdc>] (kfree) from [<c0b41bbc>] (__hwmon_device_register+0x5dc/0xa7c)
[<c0b415e0>] (__hwmon_device_register) from [<c0b421e8>] (hwmon_device_register_with_info+0xa0/0xa8)
[<c0b42148>] (hwmon_device_register_with_info) from [<c0b42324>] (devm_hwmon_device_register_with_info+0x74/0xb4)
[<c0b422b0>] (devm_hwmon_device_register_with_info) from [<c0b4481c>] (lm90_probe+0x414/0x578)
[<c0b44408>] (lm90_probe) from [<c0aeeff4>] (i2c_device_probe+0x35c/0x384)
[<c0aeec98>] (i2c_device_probe) from [<c08776cc>] (really_probe+0x290/0x3e4)
[<c087743c>] (really_probe) from [<c0877a2c>] (driver_probe_device+0x80/0x1c4)
[<c08779ac>] (driver_probe_device) from [<c0877da8>] (__device_attach_driver+0x104/0x11c)
[<c0877ca4>] (__device_attach_driver) from [<c0874dd8>] (bus_for_each_drv+0xa4/0xc8)
[<c0874d34>] (bus_for_each_drv) from [<c08773b0>] (__device_attach+0xf0/0x15c)
[<c08772c0>] (__device_attach) from [<c0877e24>] (device_initial_probe+0x1c/0x20)
[<c0877e08>] (device_initial_probe) from [<c08762f4>] (bus_probe_device+0xdc/0xec)
[<c0876218>] (bus_probe_device) from [<c0876a08>] (deferred_probe_work_func+0xa8/0xd4)
[<c0876960>] (deferred_probe_work_func) from [<c01527c4>] (process_one_work+0x3dc/0x96c)
[<c01523e8>] (process_one_work) from [<c01541e0>] (worker_thread+0x4ec/0x8bc)
[<c0153cf4>] (worker_thread) from [<c015b238>] (kthread+0x230/0x240)
[<c015b008>] (kthread) from [<c01010bc>] (ret_from_fork+0x14/0x38)
Exception stack(0xcf743fb0 to 0xcf743ff8)
3fa0:                                     00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000

Allocated by task 132:
 kasan_kmalloc.part.1+0x58/0xf4
 kasan_kmalloc+0x90/0xa4
 kmem_cache_alloc_trace+0x90/0x2a0
 __hwmon_device_register+0xbc/0xa7c
 hwmon_device_register_with_info+0xa0/0xa8
 devm_hwmon_device_register_with_info+0x74/0xb4
 lm90_probe+0x414/0x578
 i2c_device_probe+0x35c/0x384
 really_probe+0x290/0x3e4
 driver_probe_device+0x80/0x1c4
 __device_attach_driver+0x104/0x11c
 bus_for_each_drv+0xa4/0xc8
 __device_attach+0xf0/0x15c
 device_initial_probe+0x1c/0x20
 bus_probe_device+0xdc/0xec
 deferred_probe_work_func+0xa8/0xd4
 process_one_work+0x3dc/0x96c
 worker_thread+0x4ec/0x8bc
 kthread+0x230/0x240
 ret_from_fork+0x14/0x38
   (null)

Freed by task 132:
 __kasan_slab_free+0x12c/0x200
 kasan_slab_free+0x14/0x18
 kfree+0x90/0x294
 hwmon_dev_release+0x1c/0x20
 device_release+0x4c/0xe8
 kobject_put+0xac/0x11c
 device_unregister+0x2c/0x30
 __hwmon_device_register+0xa58/0xa7c
 hwmon_device_register_with_info+0xa0/0xa8
 devm_hwmon_device_register_with_info+0x74/0xb4
 lm90_probe+0x414/0x578
 i2c_device_probe+0x35c/0x384
 really_probe+0x290/0x3e4
 driver_probe_device+0x80/0x1c4
 __device_attach_driver+0x104/0x11c
 bus_for_each_drv+0xa4/0xc8
 __device_attach+0xf0/0x15c
 device_initial_probe+0x1c/0x20
 bus_probe_device+0xdc/0xec
 deferred_probe_work_func+0xa8/0xd4
 process_one_work+0x3dc/0x96c
 worker_thread+0x4ec/0x8bc
 kthread+0x230/0x240
 ret_from_fork+0x14/0x38
   (null)

Cc: <stable@vger.kernel.org> # v4.15+
Fixes: 47c332de ("hwmon: Deal with errors from the thermal subsystem")
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Trace events are useful for people who collect data from the
Ftrace outputs. There're people who analyse the relationship
of cpufreq, thermal and hwmon (power/voltage/current) using
the convenient and timestamped Ftrace outputs, while unlike
cpufreq and thermal subsystems the hwmon does not have trace
events supported yet.

So this patch adds initial trace events for the hwmon core.
To call hwmon_attr_base() for aligned attr index numbers, it
also moves the function upward.

Ftrace outputs:
 ...: hwmon_attr_show_string: index=2, attr_name=in2_label, val=VDD_5V
 ...: hwmon_attr_show: index=2, attr_name=in2_input, val=5112
 ...: hwmon_attr_show: index=2, attr_name=curr2_input, val=440

Note that the _attr_show and _attr_store functions are tied
to the _with_info API. So a hwmon driver requiring the trace
events feature should use _with_info API to register a hwmon
device.
Signed-off-by: NNicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

According to hwmon ABI, in%d_enable is a sysfs interface that
allows user space to enable and disable the input sensor. So
this patch just simply adds the attribute to the list.
Signed-off-by: NNicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Some sensors support reporting minimal and lower critical power, as
well as alarms when these thresholds are reached. Add support for
these attributes to the hwmon core.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

hwmon_device_register_with_info() registration API requires a
non-NULL parent device when chip is non-NULL.

This commit adds a check and documents this requirement.
Signed-off-by: NLucas Magasweran <lucas.magasweran@ieee.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

sparse reports:

drivers/hwmon/hwmon.c:681: warning:
	No description found for parameter 'chip'
drivers/hwmon/hwmon.c:681: warning:
	Excess function parameter 'info' description in
	'hwmon_device_register_with_info'
drivers/hwmon/hwmon.c:789: warning:
	No description found for parameter 'chip'
drivers/hwmon/hwmon.c:789: warning:
	No description found for parameter 'groups'
drivers/hwmon/hwmon.c:789: warning:
	Excess function parameter 'info' description in
	'devm_hwmon_device_register_with_info'
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

If the thermal subsystem returne -EPROBE_DEFER or any other error
when hwmon calls devm_thermal_zone_of_sensor_register(), this is
silently ignored.

I ran into this with an incorrectly defined thermal zone, making
it non-existing and thus this call failed with -EPROBE_DEFER
assuming it would appear later. The sensor was still added
which is incorrect: sensors must strictly be added after the
thermal zones, so deferred probe must be respected.

Fixes: d560168b ("hwmon: (core) New hwmon registration API")
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

The thermal_zone_of_device_ops structure is only passed as the fourth
argument to devm_thermal_zone_of_sensor_register, which is declared
as const.  Thus the thermal_zone_of_device_ops structure itself can
be const.

Done with the help of Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
   text	   data	    bss	    dec	    hex	filename
   6655	    304	      0	   6959	   1b2f	drivers/hwmon/hwmon.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
   6703	    240	      0	   6943	   1b1f	drivers/hwmon/hwmon.o
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

The read_string callback is supposed to retrieve a pointer to a
constant string.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Reviewed-by: NPeter Huewe <peterhuewe@gmx.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Rgistering a thermal zone uses devm_kzalloc(), which requires
a pointer to the parent device.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

While invalid name attributes are really not desirable and do mess up
libsensors, enforcing valid names has the detrimental effect of driving
users away from using the new hardware monitoring API, especially those
registering name attributes violating the ABI restrictions. Another
undesirable side effect is that this violation and the resulting error
may only be discovered some time after a conversion to the new API,
which in turn may trigger a revert of that conversion.

To solve the problem, relax validation and only issue a warning instead
of returning an error if a name attribute violating the ABI is provided.
This lets callers continue to provide invalid name attributes while
notifying them about it.

Many thanks are due to Dmitry Torokhov for the idea.
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

It does not make sense to use one of the the new APIs when not
even providing a name attribute. Make it mandatory.
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Use DEVICE_ATTR_RO for read-only attributes. This simplifies the source
code, improves readbility, and reduces the chance of inconsistencies.

The conversion was done automatically using coccinelle. It was validated
by compiling both the old and the new source code and comparing its text,
data, and bss size.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
[groeck: Updated description]
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Allocating the sysfs attribute name only if needed and only with the
required minimum length looks optimal, but does not take the additional
overhead for both devm_ data structures and the allocation header itself
into account. This also results in unnecessary memory fragmentation.
Move the sysfs name string into struct hwmon_device_attribute and give it
a sufficient length to reduce this overhead.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

The 'groups' parameter of hwmon_device_register_with_info() and
devm_hwmon_device_register_with_info() is only necessary if extra
non-standard attributes need to be provided. Rename the parameter
to extra_groups and clarify the documentation.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

A list of sysfs attribute groups is NULL-terminated, so we always need
to allocate data for at least two groups (the dynamically generated group
plus the NULL pointer). Add a comment to explain the situation.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

The is_visible callback provides the sysfs attribute mode and is thus
truly mandatory as documented. Check it once at registration and remove
other checks for its existence.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Inform the user that hwmon_device_register() is deprecated,
and suggest conversion to the newest API. Also remove
hwmon_device_register() from the kernel API documentation.

Note that hwmon_device_register() is not marked as __deprecated()
since doing so might result in build errors.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Describing chip attributes as "attributes which apply to the entire chip"
is confusing. Rephrase to "attributes which are not bound to a specific
input or output".

Also rename hwmon_chip_attr_templates[] to hwmon_chip_attrs[] to indicate
that the respective strings strings are not templates but actual attribute
names.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

The new API is so far only suited for data attributes and does not work
well for string attributes, specifically for the 'label' attributes.
Provide a separate callback function for those.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

If dev_kcalloc fails to allocate hw_dev->groups then the current
exit path is a direct return, causing a leak of resources such
as hwdev and ida is not removed.  Fix this by exiting via the
free_hwmon exit path that performs the necessary resource cleanup.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

If both hwmon and thermal_sys are built as modules, and
CONFIG_THERMAL_HWMON is enabled, the following cyclic module dependency
is reported.

depmod: ERROR: Found 2 modules in dependency cycles!
depmod: ERROR: Cycle detected: hwmon -> thermal_sys -> hwmon

Fixes: e4bce763adb2 ("hwmon: (core) New hwmon registration API")
Reported-by: NVignesh R <vigneshr@ti.com>
Cc: Keerthy J <j-keerthy@ti.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Add basic pwm attribute support (no auto attributes) to new API.
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Up to now, each hwmon driver has to implement its own sysfs attributes.
This requires a lot of template code, and distracts from the driver's core
function to read and write chip registers.

To be able to reduce driver complexity, move sensor attribute handling
and thermal zone registration into hwmon core. By using the new API,
driver code and data size is typically reduced by 20-70%, depending
on driver complexity and the number of sysfs attributes supported.

With this patch, the new API only supports thermal sensors. Support for
other sensor types will be added with subsequent patches.
Acked-by: NPunit Agrawal <punit.agrawal@arm.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Ordering include files alphabetically makes it easier to add new ones.
Stop including linux/spinlock.h and linux/kdev_t.h since both are not
needed.
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

hwmon name attributes must not include '-', as specified in
Documentation/hwmon/sysfs-interface. Also filter out spaces,
tabs, wildcards, and newline characters.
Tested-by: NJean Delvare <jdelvare@suse.de>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

Drivers using the new hwmon_device_register_with_groups API often have a
remove function which consists solely of a call hwmon_device_unregister().

Provide support for devm_hwmon_device_register_with_groups and
devm_hwmon_device_unregister to allow this repeated code to be removed
and help eliminate error handling code.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>