linux-kernel - Re: [PATCH] phy: allwinner: sun4i-usb: poll vbus changes on A23/A33 when driving VBUS

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Date:   Thu, 15 Mar 2018 11:59:54 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Chen-Yu Tsai <wens@...e.org>
CC:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Hans de Goede <hdegoede@...hat.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        stable <stable@...r.kernel.org>
Subject: Re: [PATCH] phy: allwinner: sun4i-usb: poll vbus changes on A23/A33
 when driving VBUS

Hi,

On Thursday 15 March 2018 11:47 AM, Chen-Yu Tsai wrote:
> Hi Kishon,
> 
> On Fri, Feb 16, 2018 at 7:20 PM, Kishon Vijay Abraham I <kishon@...com> wrote:
>>
>>
>> On Friday 19 January 2018 08:15 PM, Maxime Ripard wrote:
>>> On Fri, Jan 19, 2018 at 05:25:41PM +0800, Chen-Yu Tsai wrote:
>>>> The AXP223 PMIC, like the AXP221, does not generate VBUS change
>>>> interrupts when N_VBUSEN is used to drive VBUS for the OTG port
>>>> on the board.
>>>>
>>>> This was not noticed until recently, as most A23/A33 boards use
>>>> a GPIO pin that does not support interrupts for OTG ID detection.
>>>> This forces the driver to use polling. However the A33-OlinuXino
>>>> uses a pin that does support interrupts, so the driver uses them.
>>>> However the VBUS interrupt never fires, and the driver never gets
>>>> to update the VBUS status. This results in musb timing out waiting
>>>> for VBUS to rise.
>>>>
>>>> This was worked around for the AXP221 by resorting to polling
>>>> changes in commit 91d96f06a760 ("phy-sun4i-usb: Add workaround for
>>>> missing Vbus det interrupts on A31"). This patch adds the A23 and
>>>> A33 to the list of SoCs that need the workaround.
>>>>
>>>> Fixes: fc1f45ed3043 ("phy-sun4i-usb: Add support for the usb-phys on the
>>>>                    sun8i-a33 SoC")
>>>> Fixes: 123dfdbcfaf5 ("phy-sun4i-usb: Add support for the usb-phys on the
>>>>                    sun8i-a23 SoC")
>>>> Cc: <stable@...r.kernel.org> # 4.3.x: 68dbc2ce77bb phy-sun4i-usb:
>>>>              Use of_match_node to get model specific config data
>>>> Cc: <stable@...r.kernel.org> # 4.3.x: 5cf700ac9d50 phy: phy-sun4i-usb:
>>>>              Fix optional gpios failing probe
>>>> Cc: <stable@...r.kernel.org> # 4.3.x: 04e59a0211ff phy-sun4i-usb:
>>>>              Fix irq free conditions to match request conditions
>>>> Cc: <stable@...r.kernel.org> # 4.3.x: 91d96f06a760 phy-sun4i-usb:
>>>>              Add workaround for missing Vbus det interrupts on A31
>>>> Cc: <stable@...r.kernel.org> # 4.3.x
>>>> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
>>>> ---
>>>>
>>>> This list might get longer if the newer AXP8xx PMICs also have this
>>>> behavior. We could switch to a boolean in the per-compatible data,
>>>> or just always use polling. The yet-merged R40 support will have this
>>>> issue as well, as the R40 is paired with the AXP221. But for now,
>>>> I'd like to have something that is easier to backport to stable, so
>>>> we can at least fix this for the A23 and A33.
>>>>
>>>> Also, checkpatch.pl doesn't like the stable kernel prerequisite lines.
>>>
>>> Acked-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
>>
>> merged, thanks!
> 
> I see you moved this patch from your fixes branch to your -next branch.
> Is there any problem with the patch? Merge issues?

Decided to keep in -next since this is not a regression introduced in 4.16
kernel and stable kernels will anyways be updated.

Thanks
Kishon