hwmon: Remove I2C_CLASS_HWMON from drivers w/o detect() and address_list

Class-based I2C probing requires detect() and address_list to be
set in the I2C client driver, see checks in i2c_detect().
It's misleading to declare I2C_CLASS_HWMON support if this
precondition isn't met.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/75747c6a-d414-4b07-8f66-5a5cdddc3c36@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter") convert
back to (the new) .probe() to be able to eventually drop .probe_new() from
struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230505131718.1210071-1-u.kleine-koenig@pengutronix.de
[groeck: Added missing change in pmbus/acbel-fsg032.c]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

i2c: Make remove callback return void

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

hwmon: (occ) Prevent power cap command overwriting poll response

Currently, the response to the power cap command overwrites the
first eight bytes of the poll response, since the commands use
the same buffer. This means that user's get the wrong data between
the time of sending the power cap and the next poll response update.
Fix this by specifying a different buffer for the power cap command
response.

Fixes: 5b5513b88002 ("hwmon: Add On-Chip Controller (OCC) hwmon driver")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220628203029.51747-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Delay hwmon registration until user request

Instead of registering the hwmon device at probe time, use the
existing "occ_active" sysfs file to control when the driver polls
the OCC for sensor data and registers with hwmon. The reason for
this change is that the SBE, which is the device by which the
driver communicates with the OCC, cannot handle communications
during certain system state transitions, resulting in
unrecoverable system errors.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220427140443.11428-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Remove sequence numbering and checksum calculation

Checksumming of the request and sequence numbering is now done in the
OCC interface driver in order to keep unique sequence numbers. So
remove those in the hwmon driver. Also, add the command length to the
send_cmd function pointer, since the checksum must be placed in the
last two bytes of the command. The submit interface must receive the
exact size of the command - previously it could be rounded to the
nearest 8 bytes with no consequence.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210721190231.117185-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: use simple i2c probe function

Many hwmon drivers don't use the id information provided by the old
i2c probe function, and the remainder can easily be adapted to the new
form ("probe_new") by calling i2c_match_id explicitly.

This avoids scanning the identifier tables during probes.

Drivers which didn't use the id are converted as-is; drivers which did
are modified as follows:

* if the information in i2c_client is sufficient, that's used instead
(client->name);
* anything else is handled by calling i2c_match_id() with the same
level of error-handling (if any) as before.

A few drivers aren't included in this patch because they have a
different set of maintainers. They will be covered by other patches.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200813160222.1503401-1-steve@sk2.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Fix license headers

Files have inconsistent license information.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add sysfs attributes for additional OCC data

The OCC provides a variety of additional information about the state of
the host processor, such as throttling, error conditions, and the number
of OCCs detected in the system. This information is essential to service
processor applications such as fan control and host management.
Therefore, export this data in the form of sysfs attributes attached to
the platform device (to which the hwmon device is also attached).

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add sensor types and versions

Add structures to define all sensor types and versions. Add sysfs show
and store functions for each sensor type. Add a method to construct the
"set user power cap" command and send it to the OCC. Add rate limit to
polling the OCC (in case user-space reads our hwmon entries rapidly).

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add command transport method for P8 and P9

For the P8 OCC, add the procedure to send a command to the OCC over I2C
bus. This involves writing the OCC command registers with serial
communication operations (SCOMs) interpreted by the I2C slave. For the
P9 OCC, add a procedure to use the OCC in-kernel API to send a command
to the OCC through the SBE.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: Add On-Chip Controller (OCC) hwmon driver

The OCC is a device embedded on a POWER processor that collects and
aggregates sensor data from the processor and system. The OCC can
provide the raw sensor data as well as perform thermal and power
management on the system.

This driver provides a hwmon interface to the OCC from a service
processor (e.g. a BMC). The driver supports both POWER8 and POWER9 OCCs.
Communications with the POWER8 OCC are established over standard I2C
bus. The driver communicates with the POWER9 OCC through the FSI-based
OCC driver, which handles the lower-level communication details.

This patch lays out the structure of the OCC hwmon driver. There are two
platform drivers, one each for P8 and P9 OCCs. These are probed through
the I2C tree and the FSI-based OCC driver, respectively. The patch also
defines the first common structures and methods between the two OCC
versions.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
[groeck: Fix up SPDX license identifier]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>