The fan control feature of the w83795 driver is insufficiently
reviewed and tested for public consumption at this time, so make it
optional and disabled by default. We will change the default when
review and testing is deemed sufficient. Ultimately the option will
go away.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

I've made so many changes to the w83795 driver that it's only fair to
list myself as a co-author. I'll also maintain the driver for some
time. There's more work needed on the driver for sure.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Cleanups suggested by Guenter Roeck, falling into 4 categories:
* Swapping test orders, because if (var == CONSTANT) is much easier to
  read than if (CONSTANT == var).
* Simplifying comparisons with 0.
* Dropping unneeded masks.
* Dropping unneeded parentheses and curly braces.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Wrong index caused the wrong register value to be read, resulting in
random LSB for voltage limits.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

When we don't need the client pointer, calling dev_get_drvdata() is
more efficient that calling to_i2c_client() and then
i2c_get_clientdata().
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Wait until we need the pwm config register values, instead of
pre-reading them. This saves over 1 second on modprobe on my test
system.

Obviously this time is added when first accessing pwm config
attributes, however not everybody will use them, so it seems unfair
to slow down driver loading (and thus boot) for an optional feature.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Wait until we need the limit register values, instead of pre-reading
them. This saves 544 ms on modprobe on my test system. Obviously this
time is added when first running "sensors" or any other monitoring
application, but I think it is better than slowing down the boot.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Move initial register reads out of probe, to dedicated functions.
This makes the code clearer, and will be needed if we want to delay
calling these functions until they are needed, or want to call them
periodically.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Pack similar register reads using for loops.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Cascaded conditionals are inefficient. Reorder the fields so that
PWM register addresses can be computed more efficiently.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

There is no point in reading registers during initialization if we
will refresh the values in the update function later. This is only
slowing down the driver loading with no benefit, stop doing it.
This change saves 480 ms on driver load on my test system.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

All 3 temperature sensor type sysfs functions (show_temp_mode,
store_temp_mode and show_dts_mode) can be simplified. We don't
create these files when the correponding input isn't in temperature
monitoring mode, so there is no point in handling that case.
Likewise, we don't allow changing inputs from temperature to voltage,
so the code handling this case is dead and can be removed.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Consistently use ARRAY_SIZE() to control for loops.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Get rid of REST_VLT_BEGIN and REST_VLT_END, they don't make the code
more readable.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

x % 1 is obviously wrong, as it always evaluates to 0. You want
x % 2, or x & 1, for parity checking.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

VRLSB_SHIFT is a non-sense, the actual shift depends on the sensor
type (fans need 4, other sensors need 6). Get rid of it to prevent
any confusion. Also get rid of the useless masking, the meaningful
bits are always the MSb so there's nothing to mask out after
shifting.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Shorten driver load time by avoiding duplicate register access during
initialization. This saves 112 ms on modprobe on my test system.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Handle beep_enable just like all other beep bits. It doesn't need
anything special, so let's avoid redundant code. This also saves a
duplicate register read at initialization time.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

On systems with PECI, report PECI agent Tbase temperature values.
This is informative only.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

The temperature registers hold regular 2's complement values, no need
to add any arithmetics.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Follow the standard for temperature limit attribute naming, so that
libsensors will pick the values.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

The PWM duty cycle frequenty attributes are improperly named
(fanN_div instead of pwmN_div) and contain raw values instead of
actual frequencies. Rename them and fix their contents.

Also improve the logic when the user asks for a new frequency, to
always pick the closest supported frequency. The algorithm could
certainly be optimized, but the operation is infrequent enough that
I don't think it's worth the effort.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

The W83795G can be configured to set the in0, in1 and/or in2 voltage
limits dynamically based on VID input pins. Switch the respective
sysfs attributes to read-only.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Misplaced parentheses caused the wrong register value to be read,
resulting in random LSB for fan speed values and limits.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

* The data structure is zalloc'd, so no need to set individual fields
  to 0 explicitly.
* Refactor the handling of pins that can be used for either
  temperature or voltage monitoring.
* Misc other clean-ups.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Gain bit set means 1x gain and cleared means 8x gain, not the other
way around.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

This saves an SMBus write if monitoring was already enabled.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Attribute structures can be made const. Same for the I2C address
list.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Only create fan[1-8]_target files when the fan in question can be
controlled (PWM output is present.) Also name these files according
to the standard.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Use a dedicated 2D array for PWM attributes. This way, PWM attributes
are handled the same way as other attributes, this is more consistent.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Use 2D arrays for in, fan, temp and dts device attributes. Using
linear arrays is too risky as we have to skip some groups depending
on the device model and configuration. Adding or removing an
attribute would let the driver build silently but then it would crash
at runtime. With 2D arrays, the consistency checking happens at build
time, which is much safer.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Functions w83795_create_files and w83795_remove_files iterate over
the same set of files, just calling a different function. Merge them
into a single function which takes the action as a parameter. This
saves code, and also ensure that file creation and deletion are in
sync.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Function w83795_probe() is way too big, move file creation to a separate
function to make it more readable.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Sysfs files must be removed on device removal but also when device
registration fails. Move the code to a separate function to avoid
code redundancy.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Check for additional identification registers. Improve debugging
messages on failed detection.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Move the bank selection code to a separate function, to avoid
duplicating it in read and write functions. Improve error reporting
on register access error.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Enum chips and chip_types are redundant, get rid of the former. Fix
the detection code to properly identify the chip variant and name the
client accordingly.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

* Improve driver description.
* Drop unused macro.
* Drop unreachable code.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

There is still much work needed, but I wanted to give Wei the credit
he deserves. I've merged some of my own fixes already, to make
gcc and checkpatch happy. Individual fixes and improvements from me
will follow.

[JD: Fix build errors]
[JD: Coding style cleanups]
[JD: Get rid of forward declarations]
[JD: Drop VID support]
[JD: Drop fault output control feature]
[JD: Use lowercase for inline function names]
[JD: Use strict variants of the strtol/ul functions]
[JD: Shorten the read and write function names]
Signed-off-by: NJean Delvare <khali@linux-fr.org>