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Subject: Re: [PATCH v2 00/17] thermal: enable+check sensor after its setup
 is finished
To:     Zhang Rui <rui.zhang@intel.com>
Cc:     Eduardo Valentin <edubezval@gmail.com>,
        Amit kucheria <amit.kucheria@linaro.org>,
        Eric Anholt <eric@anholt.net>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        Markus Mayer <mmayer@broadcom.com>,
        bcm-kernel-feedback-list@broadcom.com,
        Heiko Stuebner <heiko@sntech.de>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Keerthy <j-keerthy@ti.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Jun Nie <jun.nie@linaro.org>,
        Baoyou Xie <baoyou.xie@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Message-ID: <ba5bc790-6809-e0e3-58fb-757c8c617181@samsung.com>
Date:   Mon, 5 Nov 2018 17:35:55 +0100
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On 11/05/2018 04:04 AM, Zhang Rui wrote:
> Hi, Bartlomiej,

Hi Rui,

> Interesting, I'm about to bring this issue to Linux Plumber Conference
> this year for discussion, and I'm also proposing a solution to fix the
> issues, but only with thermal core part finished yet.
> can you please take a look at it?
> https://patchwork.kernel.org/project/linux-pm/list/?series=38181

Thank you for the patches but they seem to be far from being
a complete solution for issues fixed by my patchset. Even
thermal core part is not finished yet as it doesn't provide
a way to register disabled sensors for DT thermal drivers (only
for platform ones)..

Why not simply apply my patchset now and incrementally work
on top of it to implement fixes for issues your patchset is
addressing?

My patchset may not be a perfect solution but IMO it is good
enough and it has been practically ready since v1 posted in
April (v2 fixes all issues requested by Eduardo's review from
September)..

> thanks,
> rui
> 
> On 三, 2018-10-17 at 17:52 +0200, Bartlomiej Zolnierkiewicz wrote:
>> Hi,
>>
>> [devm]_thermal_zone_of_sensor_register() is used to register
>> thermal sensor by thermal drivers using DeviceTree. Besides
>> registering sensor this function also immediately:
>>
>> - enables it:
>>
>>   tzd->ops->set_mode(tzd, THERMAL_DEVICE_ENABLED)
>>   (->set_mode is set to of_thermal_set_mode() in of-thermal.c)
>>
>> - checks it (indirectly by using of_thermal_set_mode()):
>>
>>   thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
>>   (which in turn ends up using ->get_temp method).
>>
>> For many DT thermal drivers this causes a problem because:
>>
>> - [devm]_thermal_zone_of_sensor_register() need to be called in
>>   order to obtain data about thermal trips which are then used to
>>   finish hardware sensor setup (only after which ->get_temp can
>>   be used)
>>
>> There is also related issue for DT thermal drivers that support
>> IRQ (i.e. exynos and rockchip ones):
>>
>> - sensor hardware should be enabled only after IRQ handler is
>>   requested (because otherwise we might get IRQs that we can't
>>   handle)
>>
>> - IRQ handler needs tzd structure which is obtained from
>>   [devm_]thermal_zone_of_sensor_register()
>>
>> - after [devm_]thermal_zone_of_sensor_register() call core
>>   thermal code assumes that sensor is enabled and ready to use
>>   (i.e. that IRQ handler has been requested and sensor hardware
>>   has been enabled)
>>
>> In order to fix all abovementioned issues sensor registration,
>> enable and check operations are separated in the core DT thermal
>> code and corresponding DT thermal drivers are modified to do sensor
>> setup correctly.
>>
>> Changes since v1:
>> - rebased on the current -next kernel (next-20181015)
>> - enhanced patch descriptions and cover letter
>> - renamed thermal_zone_device_toggler() to thermal_zone_set_mode()
>> - converted thermal_zone_set_mode() to use enum thermal_device_mode
>> - added CONFIG_THERMAL=n stubs for thermal_zone_set_mode() and
>>   thermal_zone_device_check()
>> - fixed uses of [devm]_thermal_zone_of_sensor_register() outside of
>>   drivers/thermal/
>> - changed ordering between patch #2 and #3 in order to add all
>>   needed core helpers first before fixing sensor setup code
>> - changed ordering between patch #3 and #4 in order to simplify them
>> - renamed patch #3 to "thermal: separate sensor enable and check
>>   operations"
>> - renamed patch #4 to "thermal: separate sensor registration and
>>   enable+check operations"
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
>>
>> Bartlomiej Zolnierkiewicz (17):
>>   thermal: add thermal_zone_set_mode() helper
>>   thermal: add thermal_zone_device_check() helper
>>   thermal: separate sensor enable and check operations
>>   thermal: separate sensor registration and enable+check operations
>>   thermal: bcm2835: enable+check sensor after its setup is finished
>>   thermal: brcmstb: enable+check sensor after its setup is finished
>>   thermal: hisi_thermal: enable+check sensor after its setup is
>> finished
>>   thermal: qcom: tsens: enable+check sensor after its setup is
>> finished
>>   thermal: qoriq: enable+check sensor after its setup is finished
>>   thermal: rcar_gen3_thermal: enable+check sensor after its setup is
>>     finished
>>   thermal: rockchip_thermal: enable+check sensor after its setup is
>>     finished
>>   thermal: exynos: enable+check sensor after its setup is finished
>>   thermal: tegra: enable+check sensor after its setup is finished
>>   thermal: ti-soc-thermal: enable+check sensor after its setup is
>>     finished
>>   thermal: uniphier: enable+check sensor after its setup is finished
>>   thermal: zx2967: enable+check sensor after its setup is finished
>>   thermal: warn on attempts to read temperature on disabled sensors
>>
>>  drivers/acpi/thermal.c                             |  5 +--
>>  drivers/ata/ahci_imx.c                             | 10 ++++--
>>  drivers/hwmon/hwmon.c                              |  5 +++
>>  drivers/hwmon/ntc_thermistor.c                     |  4 +++
>>  drivers/hwmon/scpi-hwmon.c                         |  4 +++
>>  drivers/iio/adc/sun4i-gpadc-iio.c                  |  5 +++
>>  drivers/input/touchscreen/sun4i-ts.c               |  8 ++++-
>>  drivers/net/ethernet/mellanox/mlxsw/core_thermal.c |  1 -
>>  drivers/platform/x86/acerhdf.c                     |  6 +++-
>>  drivers/regulator/max8973-regulator.c              |  6 ++--
>>  drivers/thermal/armada_thermal.c                   |  3 ++
>>  drivers/thermal/broadcom/bcm2835_thermal.c         |  3 ++
>>  drivers/thermal/broadcom/brcmstb_thermal.c         |  3 ++
>>  drivers/thermal/broadcom/ns-thermal.c              |  3 ++
>>  drivers/thermal/da9062-thermal.c                   |  7 ++--
>>  drivers/thermal/db8500_thermal.c                   |  5 ++-
>>  drivers/thermal/hisi_thermal.c                     | 22 ++++------
>> ---
>>  drivers/thermal/imx_thermal.c                      |  3 +-
>>  drivers/thermal/int340x_thermal/int3400_thermal.c  |  1 +
>>  drivers/thermal/intel_bxt_pmic_thermal.c           |  3 +-
>>  drivers/thermal/intel_soc_dts_iosf.c               |  3 +-
>>  drivers/thermal/max77620_thermal.c                 |  6 ++--
>>  drivers/thermal/mtk_thermal.c                      |  3 ++
>>  drivers/thermal/of-thermal.c                       |  6 ++--
>>  drivers/thermal/qcom-spmi-temp-alarm.c             |  5 ++-
>>  drivers/thermal/qcom/tsens.c                       |  6 ++++
>>  drivers/thermal/qoriq_thermal.c                    |  3 ++
>>  drivers/thermal/rcar_gen3_thermal.c                |  7 ++--
>>  drivers/thermal/rcar_thermal.c                     |  7 ++--
>>  drivers/thermal/rockchip_thermal.c                 | 38 +++++++++++-
>> ----------
>>  drivers/thermal/samsung/exynos_tmu.c               |  7 +++-
>>  drivers/thermal/st/st_thermal_memmap.c             |  3 +-
>>  drivers/thermal/tango_thermal.c                    |  5 +++
>>  drivers/thermal/tegra/soctherm.c                   |  3 ++
>>  drivers/thermal/tegra/tegra-bpmp-thermal.c         |  3 ++
>>  drivers/thermal/thermal-generic-adc.c              |  3 ++
>>  drivers/thermal/thermal_core.c                     | 14 ++++----
>>  drivers/thermal/thermal_helpers.c                  | 32
>> ++++++++++++++++++
>>  drivers/thermal/thermal_sysfs.c                    | 17 ++++++----
>>  drivers/thermal/ti-soc-thermal/ti-thermal-common.c |  7 +++-
>>  drivers/thermal/uniphier_thermal.c                 |  6 +++-
>>  drivers/thermal/x86_pkg_temp_thermal.c             |  2 +-
>>  drivers/thermal/zx2967_thermal.c                   |  3 ++
>>  include/linux/thermal.h                            | 11 +++++++
>>  44 files changed, 220 insertions(+), 87 deletions(-)

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics