linux-kernel - Re: [PATCH 02/13] platform/x86: dmi_device_properties: Add setup info for boards with a CHT Whiskey Cove PMIC

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Date:   Mon, 8 Nov 2021 16:48:33 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andy@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Sebastian Reichel <sre@...nel.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Yauhen Kharuzhy <jekhor@...il.com>,
        Tsuchiya Yuto <kitakar@...il.com>,
        platform-driver-x86@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-efi@...r.kernel.org
Subject: Re: [PATCH 02/13] platform/x86: dmi_device_properties: Add setup info
 for boards with a CHT Whiskey Cove PMIC

Hi Andy,

Thank you for your feedback.

On 10/30/21 23:56, Andy Shevchenko wrote:
> On Sat, Oct 30, 2021 at 9:28 PM Hans de Goede <hdegoede@...hat.com> wrote:
>>
>> Add a new "intel,cht-wc-setup" string property to the "INT34D3:00"
>> i2c_client for the Whiskey Cove PMIC found on several Cherry Trail
>> based devices. At least 3 setups are known:
>>
>> 1. The WC PMIC is connected to a TI BQ24292i charger, paired with
>>    a Maxim MAX17047 fuelgauge + a FUSB302 USB Type-C Controller +
>>    a PI3USB30532 USB switch, for a fully functional Type-C port
>>
>> 2. The WC PMIC is connected to a TI BQ25890 charger, paired with
>>    a TI BQ27520 fuelgauge, for a USB-2 only Type-C port without PD
>>
>> 3. The WC PMIC is connected to a TI BQ25890 charger, paired with
>>    a TI BQ27542 fuelgauge, for a micro-USB port
>>
>> Which setup is in use cannot be determined reliably from the ACPI tables
>> and various drivers (extcon-intel-cht-wc.c, i2c-cht-wc.c, ...) need
>> to know which setup they are dealing with.
> 
> If it's internal property only, I would rather expect it to start with
> 'linux,' as DWC3 does. And it's also USB related.
> 
> ...
> 
>> +       PROPERTY_ENTRY_STRING("intel,cht-wc-setup", "bq24292i,max17047,fusb302,pi3usb30532"),
> 
>> +       PROPERTY_ENTRY_STRING("intel,cht-wc-setup", "bq25890,bq27520"),
> 
>  Besides that I'm not sure about the name of the property, maybe
> 'linux,cht-wc-usb-chips' or alike? And since it's a list, can we make
> it a string array?
> 

So now that I also have a yogabook to test on it has become clear that
we really need to treat each device-model/board with a cht-wc PMIC
differently in the various cht-wc MFD cell drivers.

So instead of using device-properties (patch 1 + 2 from this series)
I've chosen to add a intel_cht_wc_get_model( helper to:
drivers/mfd/intel_soc_pmic_chtwc.c

Which uses DMI matching (in a shared place so that we need the DMI
table only once) and returns an enum value which represents all
known boards.

Regards,

Hans