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Date:   Mon, 12 Jul 2021 13:35:43 +0200
From:   Henning Schild <henning.schild@siemens.com>
To:     Hans de Goede <hdegoede@redhat.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
        platform-driver-x86@vger.kernel.org,
        linux-watchdog@vger.kernel.org,
        Srikanth Krishnakar <skrishnakar@gmail.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        Gerd Haeussler <gerd.haeussler.ext@siemens.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Mark Gross <mgross@linux.intel.com>,
        Pavel Machek <pavel@ucw.cz>, Enrico Weigelt <lkml@metux.net>
Subject: Re: [PATCH v3 0/4] add device drivers for Siemens Industrial PCs
Message-ID: <20210712133543.074aad80@md1za8fc.ad001.siemens.net>
In-Reply-To: <857d6cd4-839d-c42a-0aa7-8d45243981ee@redhat.com>
References: <20210329174928.18816-1-henning.schild@siemens.com>
        <857d6cd4-839d-c42a-0aa7-8d45243981ee@redhat.com>
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This series is basically stuck because people rightfully want me to use
the GPIO subsystem for the LEDs and the watchdog bits that are
connected to GPIO.

Problem is that the GPIO subsystem does not initialize on the machines
in question. It is a combination of hidden P2SB and missing ACPI table
entries. The GPIO subsystem (intel pinctrl) needs either P2SB or ACPI do
come up ...

Andy proposed some patches for initializing the intel pinctrl stuff for
one of the machines by falling back to SoC detection in case there is
no ACPI or visible P2SB. While that works it would need to be done for
any Intel SoC to be consistent and discussions seem to go nowhere.

I would be willing to port over to "intel pintctl" and help with
testing, but not so much with actual coding. Andy is that moving at all?

Since my drivers do reserve the mmio regions properly and the intel
pinctrl will never come up anyways, i do not see a conflict merging my
proposed drivers in the current codebase. The wish to use the pinctrl
infrastructure can not be fulfilled if that infra is not in place. Once
intel pinctrl works, we can change those drivers to work with that.

I do not want to take shortcuts ... but also do not want to get stuck
here. So maybe one way to serialize the merge is to allow my changes
like proposed and rebase on intel pinctrl once that subsystem actually
initializes on these machines. We could even have two code paths ... if
region can not be reserved, try gpio ... or the other way around.

regards,
Henning

Am Wed, 7 Apr 2021 13:36:40 +0200
schrieb Hans de Goede <hdegoede@redhat.com>:

> Hi,
> 
> On 3/29/21 7:49 PM, Henning Schild wrote:
> > changes since v2:
> > 
> > - remove "simatic-ipc" prefix from LED names
> > - fix style issues found in v2, mainly LED driver
> > - fix OEM specific dmi code, and remove magic numbers
> > - more "simatic_ipc" name prefixing
> > - improved pmc quirk code using callbacks
> > 
> > changes since v1:
> > 
> > - fixed lots of style issues found in v1
> >   - (debug) printing
> >   - header ordering
> > - fixed license issues GPLv2 and SPDX in all files
> > - module_platform_driver instead of __init __exit
> > - wdt simplifications cleanup
> > - lots of fixes in wdt driver, all that was found in v1
> > - fixed dmi length in dmi helper
> > - changed LED names to allowed ones
> > - move led driver to simple/
> > - switched pmc_atom to dmi callback with global variable
> > 
> > --
> > 
> > This series adds support for watchdogs and leds of several x86
> > devices from Siemens.
> > 
> > It is structured with a platform driver that mainly does
> > identification of the machines. It might trigger loading of the
> > actual device drivers by attaching devices to the platform bus.
> > 
> > The identification is vendor specific, parsing a special binary DMI
> > entry. The implementation of that platform identification is
> > applied on pmc_atom clock quirks in the final patch.
> > 
> > It is all structured in a way that we can easily add more devices
> > and more platform drivers later. Internally we have some more code
> > for hardware monitoring, more leds, watchdogs etc. This will follow
> > some day.  
> 
> IT seems there still is significant discussion surrounding the LED
> and watchdog drivers which use patch 1/4 as parent-driver.
> 
> I'm going to hold of on merging 1/4 and 4/4 until there is more
> consensus surrounding this series.
> 
> Regards,
> 
> Hans
> 
> 
> > 
> > Henning Schild (4):
> >   platform/x86: simatic-ipc: add main driver for Siemens devices
> >   leds: simatic-ipc-leds: add new driver for Siemens Industial PCs
> >   watchdog: simatic-ipc-wdt: add new driver for Siemens Industrial
> > PCs platform/x86: pmc_atom: improve critclk_systems matching for
> > Siemens PCs
> > 
> >  drivers/leds/Kconfig                          |   3 +
> >  drivers/leds/Makefile                         |   3 +
> >  drivers/leds/simple/Kconfig                   |  11 +
> >  drivers/leds/simple/Makefile                  |   2 +
> >  drivers/leds/simple/simatic-ipc-leds.c        | 202
> > ++++++++++++++++ drivers/platform/x86/Kconfig                  |
> > 12 + drivers/platform/x86/Makefile                 |   3 +
> >  drivers/platform/x86/pmc_atom.c               |  57 +++--
> >  drivers/platform/x86/simatic-ipc.c            | 169 ++++++++++++++
> >  drivers/watchdog/Kconfig                      |  11 +
> >  drivers/watchdog/Makefile                     |   1 +
> >  drivers/watchdog/simatic-ipc-wdt.c            | 215
> > ++++++++++++++++++ .../platform_data/x86/simatic-ipc-base.h      |
> > 29 +++ include/linux/platform_data/x86/simatic-ipc.h |  72 ++++++
> >  14 files changed, 769 insertions(+), 21 deletions(-)
> >  create mode 100644 drivers/leds/simple/Kconfig
> >  create mode 100644 drivers/leds/simple/Makefile
> >  create mode 100644 drivers/leds/simple/simatic-ipc-leds.c
> >  create mode 100644 drivers/platform/x86/simatic-ipc.c
> >  create mode 100644 drivers/watchdog/simatic-ipc-wdt.c
> >  create mode 100644
> > include/linux/platform_data/x86/simatic-ipc-base.h create mode
> > 100644 include/linux/platform_data/x86/simatic-ipc.h 
>