linux-kernel - Re: [PATCH 0/2] extcon: Intel Cherry Trail Whiskey Cove PMIC and external charger tweaks

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Date:   Thu, 14 Feb 2019 00:00:44 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Yauhen Kharuzhy <jekhor@...il.com>, linux-kernel@...r.kernel.org
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 0/2] extcon: Intel Cherry Trail Whiskey Cove PMIC and
 external charger tweaks

Hi,

On 10-02-19 21:36, Yauhen Kharuzhy wrote:
> At implementation of charging support for Lenovo Yoga Book (Intel Cherry Trail
> based with Whiskey Cove PMIC), two pitfalls were found:
> 
> - for detection of charger type by PMIC, bit 6 in the CHGRCTRL1 register
>    should be set in 0 (and set to 1 for Host mode). Pick up its definition
>    and logic from from Intel code drop[1];
> 
> - "#CHARGE ENABLE" signal of external charger (bq25892) in Yoga Book is
>    connected to one of PMIC outputs controlled by CHGDISCTRL register.
>    Enable charging at driver initialization. Pick up this from Lenovo's code
>    drop[2,3].
> 
> Please keep in mind that I have no docs for Whiskey Cove PMIC, so this patches
> are based on some kind of reverse engineering and suppositions, correct me if
> this semantic is wrong for common case.
> 
> [1]. https://github.com/01org/ProductionKernelQuilts/uefi/cht-m1stable/patches/0001-power_supply-intel-pmic-ccsm-driver.patch
> [2]. https://github.com/jekhor/yogabook-linux-android-kernel/blob/b7aa015ab794b516da7b6cb76e5e2d427e3b8b0c/drivers/power/bq2589x_charger.c#L2257
> [3]. https://github.com/01org/ProductionKernelQuilts/uefi/cht-m1stable/patches/EM-Charger-Disable-battery-charging-in-S3-and-enable.patch

Thank you for these patches, besides your Lenovo Yoga Book I'm aware of
only 2 other device models using the CHT Whiskey Cove PMIC, the GPD win
and GPD pocket devices. These both work fine without the changes your
patches introduce.

I need to check if your changes do not cause regressions on these 2
devices, which are used with Linux by quite a few people. I will try
to make some time for testing this sometime next week.

A kind request to the platform-x86 driver maintainers (hi Andy): Please
do not apply these patches until I've been able to test they don't cause
issues elsewhere.

Regards,

Hans