linux-kernel - Re: [PATCH 12/12] extcon: axp288: Set USB role where necessary

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Message-ID: <20180216134545.GR1480@kuha.fi.intel.com>
Date:   Fri, 16 Feb 2018 15:45:45 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH 12/12] extcon: axp288: Set USB role where necessary

On Fri, Feb 16, 2018 at 11:47:51AM +0100, Hans de Goede wrote:
> The AXP288 BC1.2 charger detection / extcon code may seem like a strange
> place to add code to control the USB role-switch on devices with an AXP288,
> but there are 2 reasons to do this inside the axp288 extcon code:
> 
> 1) On many devices the USB role is controlled by ACPI AML code, but the AML
>    code only switches between the host and none roles, because of Windows
>    not really using device mode. To make device mode work we need to toggle
>    between the none/device roles based on VBus presence, and the axp288
>    extcon gets interrupts on VBus insertion / removal.
> 
> 2) In order for our BC1.2 charger detection to work properly the role
>    mux must be properly set to device mode before we do the detection.
> 
> Also note the Kconfig help-text / obsolete depends on USB_PHY which are
> remnants from older never upstreamed code also controlling the mux from
> the axp288 extcon code.
> 
> This commit also adds code to get notifications from the INT3496 extcon
> device, which is used on some devices to notify the kernel about id-pin
> changes instead of them being handled through AML code.
> 
> This fixes:
> -Device mode not working on most CHT devices with an AXP288
> -Host mode not working on devices with an INT3496 ACPI device
> -Charger-type misdetection (always SDP) on devices with an INT3496 when the
>  USB role (always) gets initialized as host
> 
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>

After addressing Andy's comments:

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>


Thanks,

-- 
heikki