cpufreq: mediatek-hw: Don't error out if supply is not found

devm_regulator_get_optional() returns -ENODEV if no supply can be found.
By introducing its usage, commit 788715b5f21c ("cpufreq: mediatek-hw:
Wait for CPU supplies before probing") caused the driver to fail probe
if no supply was present in any of the CPU DT nodes.

Use devm_regulator_get() instead since the CPUs do require supplies
even if not described in the DT. It will gracefully return a dummy
regulator if none is found in the DT node, allowing probe to succeed.

Fixes: 788715b5f21c ("cpufreq: mediatek-hw: Wait for CPU supplies before probing")
Reported-by: kernelci.org bot <bot@kernelci.org>
Closes: https://linux.kernelci.org/test/case/id/65b0b169710edea22852a3fa/
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: mediatek-hw: Wait for CPU supplies before probing

Before proceeding with the probe and enabling frequency scaling for the
CPUs, make sure that all supplies feeding the CPUs have probed.

This fixes an issue observed on MT8195-Tomato where if the
mediatek-cpufreq-hw driver enabled the hardware (by writing to
REG_FREQ_ENABLE) before the SPMI controller driver (spmi-mtk-pmif),
behind which lies the big CPU supply, probed the platform would hang
shortly after with "rcu: INFO: rcu_preempt detected stalls on
CPUs/tasks" being printed in the log.

Fixes: 4855e26bcf4d ("cpufreq: mediatek-hw: Add support for CPUFREQ HW")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: mediatek-hw: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: 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>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: Make cpufreq_unregister_driver() return void

All but a few drivers ignore the return value of
cpufreq_unregister_driver(). Those few that don't only call it after
cpufreq_register_driver() succeeded, in which case the call doesn't
fail.

Make the function return no value and add a WARN_ON for the case that
the function is called in an invalid situation (i.e. without a previous
successful call to cpufreq_register_driver()).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com> # brcmstb-avs-cpufreq.c
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: mediatek-hw: Register to module device table

Register the compatibles for this module on the module device table so
it can be automatically loaded when a matching device is found on the
system.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: Generalize of_perf_domain_get_sharing_cpumask phandle format

of_perf_domain_get_sharing_cpumask currently assumes a 1-argument
phandle format, and directly returns the argument. Generalize this to
return the full of_phandle_args, so it can be used by drivers which use
other phandle styles (e.g. separate nodes). This also requires changing
the CPU sharing match to compare the full args structure.

Also, make sure to of_node_put(args.np) (the original code was leaking a
reference).

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

PM: EM: convert power field to micro-Watts precision and align drivers

The milli-Watts precision causes rounding errors while calculating
efficiency cost for each OPP. This is especially visible in the 'simple'
Energy Model (EM), where the power for each OPP is provided from OPP
framework. This can cause some OPPs to be marked inefficient, while
using micro-Watts precision that might not happen.

Update all EM users which access 'power' field and assume the value is
in milli-Watts.

Solve also an issue with potential overflow in calculation of energy
estimation on 32bit machine. It's needed now since the power value
(thus the 'cost' as well) are higher.

Example calculation which shows the rounding error and impact:

power = 'dyn-power-coeff' * volt_mV * volt_mV * freq_MHz

power_a_uW = (100 * 600mW * 600mW * 500MHz) / 10^6 = 18000
power_a_mW = (100 * 600mW * 600mW * 500MHz) / 10^9 = 18

power_b_uW = (100 * 605mW * 605mW * 600MHz) / 10^6 = 21961
power_b_mW = (100 * 605mW * 605mW * 600MHz) / 10^9 = 21

max_freq = 2000MHz

cost_a_mW = 18 * 2000MHz/500MHz = 72
cost_a_uW = 18000 * 2000MHz/500MHz = 72000

cost_b_mW = 21 * 2000MHz/600MHz = 70 // <- artificially better
cost_b_uW = 21961 * 2000MHz/600MHz = 73203

The 'cost_b_mW' (which is based on old milli-Watts) is misleadingly
better that the 'cost_b_uW' (this patch uses micro-Watts) and such
would have impact on the 'inefficient OPPs' information in the Cpufreq
framework. This patch set removes the rounding issue.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: EM: Change the order of arguments in the .active_power() callback

The .active_power() callback passes the device pointer when it's called.
Aligned with a convetion present in other subsystems and pass the 'dev'
as a first argument. It looks more cleaner.

Adjust all affected drivers which implement that API callback.

Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: mediatek-hw: Fix double devm_remap in hotplug case

When hotpluging policy cpu, cpu policy init will be called multiple times.
Unplug CPU7 -> CPU6 -> CPU5 -> CPU4, then plug CPU4 again.
In this case, devm_remap will double remap and resource allocate fail.
So replace devm_remap to ioremap and release resources in cpu policy exit.

Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: mediatek-hw: Fix cpufreq_table_find_index_dl() call

The new cpufreq table flag RELATION_E introduced a new "efficient"
parameter for the cpufreq_table_find*() functions.

Fixes: 1f39fa0dccff (cpufreq: Introducing CPUFREQ_RELATION_E)
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: mediatek-hw: Add support for CPUFREQ HW

Introduce cpufreq HW driver which can support
CPU frequency adjust in MT6779 platform.

Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
[ Viresh: Massaged the patch and cleaned some stuff. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>