Commit graph

21 commits

Author SHA1 Message Date
Rob Herring
39f034386f hwmon: Explicitly include correct DT includes
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230714174607.4057185-1-robh@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-08-21 06:04:29 -07:00
Paul Fertser
3b1ea71fac hwmon: (aspeed-pwm-tacho) increase fan tach period (again)
The old value allows measuring fan speeds down to about 970 RPM and
gives timeout for anything less than that. It is problematic because it
can also be used as an indicator for fan failure or absence.

Despite having read the relevant section of "ASPEED AST2500/AST2520 A2
Datasheet – V1.7" multiple times I wasn't able to figure out what
exactly "fan tach period" and "fan tach falling point of period" mean
(both are set by the driver from the constant this patch is amending).

Experimentation with a Tioga Pass OCP board (AST2500 BMC) showed that
value of 0x0108 gives time outs for speeds below 1500 RPM and the value
offered by the patch is good for at least 750 RPM (the fans can't spin
any slower so the lower bound is unknown). Measuring with the fans
spinning takes about 30 ms, sometimes down to 18 ms, so about the same
as with the previous value.

This constant was last changed with commit 762b1e8880 ("hwmon:
(aspeed-pwm-tacho) increase fan tach period")

Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Link: https://lore.kernel.org/r/20220714142344.27071-1-fercerpav@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2022-07-21 07:15:55 -07:00
Tian Tao
da75b22452 hwmon: (aspeed-pwm-tacho) Switch to using the new API kobj_to_dev()
fixed the following coccicheck:
drivers/hwmon/aspeed-pwm-tacho.c:634:60-61: WARNING opportunity for
kobj_to_dev()
drivers/hwmon/aspeed-pwm-tacho.c:623:60-61: WARNING opportunity for
kobj_to_dev()

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/1609725945-13895-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2021-01-27 17:44:18 -08:00
Evgeny Novikov
bc4071aafc hwmon: (aspeed-pwm-tacho) Avoid possible buffer overflow
aspeed_create_fan() reads a pwm_port value using of_property_read_u32().
If pwm_port will be more than ARRAY_SIZE(pwm_port_params), there will be
a buffer overflow in
aspeed_create_pwm_port()->aspeed_set_pwm_port_enable(). The patch fixes
the potential buffer overflow.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
Link: https://lore.kernel.org/r/20200703111518.9644-1-novikov@ispras.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2020-07-05 20:45:45 -07:00
Markus Elfring
7b10e17067 hwmon: (aspeed-pwm-tacho) Use devm_platform_ioremap_resource() in aspeed_pwm_tacho_probe()
Simplify this function implementation by using a known wrapper function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Link: https://lore.kernel.org/r/cd5bab7b-9333-2a43-bcf0-a47bbbe719eb@web.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2019-11-06 14:37:18 -08:00
Thomas Gleixner
3a63cbb8db treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 3
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 version 2 or
  later as published by the free software foundation

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154040.848507137@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 11:28:40 +02:00
Guenter Roeck
389c0ad1d6 hwmon: (aspeed-pwm-tacho) Use devm_thermal_of_cooling_device_register
Use devm_thermal_of_cooling_device_register() to register the cooling
device. As a side effect, this fixes a driver bug:
thermal_cooling_device_unregister() was not called on removal.

Fixes: f198907d2f ("hwmon: (aspeed-pwm-tacho) cooling device support.")
Cc: Mykola Kostenok <c_mykolak@mellanox.com>
Cc: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Patrick Venture <venture@google.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2019-05-14 07:00:44 -07:00
Guenter Roeck
e98dd5388b hwmon: (aspeed-pwm-tacho) Use permission specific SENSOR[_DEVICE]_ATTR variants
Use SENSOR[_DEVICE]_ATTR[_2]_{RO,RW,WO} to simplify the source code,
to improve readbility, and to reduce the chance of inconsistencies.

Also replace any remaining S_<PERMS> in the driver 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.

Cc: Joel Stanley <joel@jms.id.au>
Cc: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2018-12-16 15:13:39 -08:00
Rob Herring
0debe4d0b8 hwmon: Convert to using %pOFn instead of device_node.name
In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.

Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2018-10-10 20:37:13 -07:00
Kees Cook
a86854d0c5 treewide: devm_kzalloc() -> devm_kcalloc()
The devm_kzalloc() function has a 2-factor argument form, devm_kcalloc().
This patch replaces cases of:

        devm_kzalloc(handle, a * b, gfp)

with:
        devm_kcalloc(handle, a * b, gfp)

as well as handling cases of:

        devm_kzalloc(handle, a * b * c, gfp)

with:

        devm_kzalloc(handle, array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        devm_kcalloc(handle, array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        devm_kzalloc(handle, 4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

Some manual whitespace fixes were needed in this patch, as Coccinelle
really liked to write "=devm_kcalloc..." instead of "= devm_kcalloc...".

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
expression HANDLE;
type TYPE;
expression THING, E;
@@

(
  devm_kzalloc(HANDLE,
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  devm_kzalloc(HANDLE,
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression HANDLE;
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
expression HANDLE;
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
expression HANDLE;
identifier SIZE, COUNT;
@@

- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression HANDLE;
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression HANDLE;
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
expression HANDLE;
identifier STRIDE, SIZE, COUNT;
@@

(
  devm_kzalloc(HANDLE,
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression HANDLE;
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression HANDLE;
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  devm_kzalloc(HANDLE, sizeof(THING) * C2, ...)
|
  devm_kzalloc(HANDLE, sizeof(TYPE) * C2, ...)
|
  devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
  devm_kzalloc(HANDLE, C1 * C2, ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	(E1) * E2
+	E1, E2
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 16:19:22 -07:00
Joel
18c514cc0e hwmon: (aspeed-pwm-tacho) Deassert reset in probe
The ASPEED SoC must deassert a reset in order to use the PWM/tach
peripheral.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2018-01-02 15:05:34 -08:00
Joel
54b943e696 hwmon: (aspeed-pwm-tacho) Sort headers
Sort the headers in preperation for future changes.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-11-04 11:09:34 -07:00
Patrick Venture
762b1e8880 hwmon: (aspeed-pwm-tacho) increase fan tach period
The previous value reduced the time required to determine
the fan value, however, it's also used as the final timeout
mechanism.  The prevous value would work for any fan speed
greater than around 3k RPM.  This increased value, lets the fan
speeds return quickly but will wait longer to handle speeds below 3k
RPM.

Testing: this value was determined through experimentation on the ast2400
on the Quanta-q71l.  This configurations runs 8 fans attached to the
controller.

Signed-off-by: Patrick Venture <venture@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-10-29 18:36:03 -07:00
Mykola Kostenok
f198907d2f hwmon: (aspeed-pwm-tacho) cooling device support.
Add support in aspeed-pwm-tacho driver for cooling device creation.
This cooling device could be bound to a thermal zone
for the thermal control. Device will appear in /sys/class/thermal
folder as cooling_deviceX. Then it could be bound to particular
thermal zones. Allow specification of the cooling levels
vector - PWM duty cycle values in a range from 0 to 255
which correspond to thermal cooling states.

Signed-off-by: Mykola Kostenok <c_mykolak@mellanox.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-08-13 08:24:38 -07:00
Patrick Venture
44b413661b hwmon: (aspeed-pwm-tacho) Poll with short sleeps.
The reference driver polled but mentioned it was possible to sleep
for a computed period to know when it's ready to read.  However, polling
with minimal sleeps is quick and works.  This also improves responsiveness
from the driver.

Testing: tested on ast2400 on quanta-q71l

Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-06-24 08:58:06 -07:00
Patrick Venture
ece0c03a9e hwmon: (aspeed-pwm-tacho) reduce fan_tach period
Reduce the fan_tach period such that the fan controller uses a shorter
period to measure the rpm.

The original period of 0x1000 was chosen as a conversative value from the
reference implementation.  Through experimentation on the quanta-q71l
board, I was able to drive the number down which ultimately reduced the
time the controller would use to determine the fan_tach.  This value was
recently tested and accepted downstream on the IBM Zaius board which uses
the ast2500.

Future work: It may be worthwhile as this is a tunable parameter to the
system, to allow overriding it through the device tree.

Testing: Tested on an ast2400 sitting on a quanta-q71l and ast2500 on
power9.

Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-06-24 08:57:42 -07:00
Patrick Venture
1e276292bf hwmon: (aspeed-pwm-tacho) Enable both edge measurement.
The aspeed-pwm-tacho controller supports measuring the fan tach by using
leading, falling, or both edges.  This change allows the driver to
support either of the three configurations and will appropriately modify
the returned tach data.

If the controller is measuring with both edges it can return a value more
quickly to the requestor.  This version of the driver should still take ~1s
to return with an RPM value per fan, however, it can be tuned faster with
double edge counting enabled than without.

I tested this and found the number returned matched what I expected.

Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-06-11 17:08:19 -07:00
Stefan Schaeckeler
5f348fa35a hwmon: (aspeed-pwm-tacho) make fan/pwm names start with index 1
Make fan and pwm names in sysfs start with index 1 in accordance to
Documentation/hwmon/sysfs-interface conventions.

Current implementation starts with index 0, making tools such as
sensors(1) skip the first fan.

Signed-off-by: Stefan Schaeckeler <sschaeck@cisco.com>
Fixes: 2d7a548a3e ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-06-03 03:55:43 -07:00
Stefan Schaeckeler
4d58e7329f hwmon: (aspeed-pwm-tacho) Call of_node_put() on a node not claimed
Call of_node_put() on a node claimed with of_node_get() or by any other
means such as for_each_child_of_node().

Signed-off-by: Stefan Schaeckeler <sschaeck@cisco.com>
Fixes: 2d7a548a3e ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-06-03 03:54:00 -07:00
Patrick Venture
7ed1c5e5dd hwmon: (aspeed-pwm-tacho) On read failure return -ETIMEDOUT
When the controller fails to provide an RPM reading within the alloted
time; the driver returns -ETIMEDOUT and no file contents.

Signed-off-by: Patrick Venture <venture@google.com>
Fixes: 2d7a548a3e ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-05-30 15:15:40 -07:00
Jaghathiswari Rankappagounder Natarajan
2d7a548a3e drivers: hwmon: Support for ASPEED PWM/Fan tach
The ASPEED AST2400/2500 PWM controller supports 8 PWM output ports.
The ASPEED AST2400/2500 Fan tach controller supports 16 tachometer
inputs.
The device driver matches on the device tree node. The configuration
values are read from the device tree and written to the respective
registers.
The driver provides a sysfs entries through which the user can
configure the duty-cycle value (ranging from 0 to 100 percent) and read
the fan tach rpm value.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-04-10 13:12:18 -07:00