linux-kernel - Re: [PATCH v4 1/3] phy: amlogic: phy-meson-gxl-usb2: fix shared reset controller use

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Date:   Tue, 7 Dec 2021 12:20:52 +0100
From:   Amjad Ouled-Ameur <aouledameur@...libre.com>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        p.zabel@...gutronix.de
Cc:     khilman@...libre.com, balbi@...nel.org, jbrunet@...libre.com,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH v4 1/3] phy: amlogic: phy-meson-gxl-usb2: fix shared reset
 controller use

Hi Martin,

Thank you for the thorough review.


On 06/12/2021 22:19, Martin Blumenstingl wrote:
> Hi Amjad,
>
> On Sun, Dec 5, 2021 at 10:59 PM Amjad Ouled-Ameur
> <aouledameur@...libre.com> wrote:
>> Use reset_control_rearm() call if an error occurs in case
>> phy_meson_gxl_usb2_init() fails after reset() has been called ; or in case
>> phy_meson_gxl_usb2_exit() is called i.e the resource is no longer used
>> and the reset line may be triggered again by other devices.
>>
>> reset_control_rearm() keeps use of triggered_count sane in the reset
>> framework. Therefore, use of reset_control_reset() on shared reset line
>> should be balanced with reset_control_rearm().
>>
>> Signed-off-by: Amjad Ouled-Ameur <aouledameur@...libre.com>
>> Reported-by: Jerome Brunet <jbrunet@...libre.com>
>> ---
>> changes since v3:
>> - Remove unnecessary reset_control_rearm() after reset_control_reset()
>> failure.
> I double-checked your patch in v3 and Philipp was right:
> reset_control_rearm() should not be right after reset_control_reset().
> However, I think reset_control_rearm() is still needed
> phy_meson_gxl_usb2_init() whenever clk_prepare_enable() fails.

Well seen, reset_control_rearm() should actually be called after

clk_prepare_enable() fails. I will wait for any other potential reviews

before sending next version with this change you suggested.


Thank you Martin.

Amjad

> So my suggestion is to add reset_control_rearm() in
> phy_meson_gxl_usb2_init() if clk_prepare_enable() fails so we are
> resetting the ref-count for the reset line (just like
> phy_meson_gxl_usb2_exit() does).
> The difference compared to the previous version is that the
> reset_control_rearm() call needs to be placed a few lines down.
>
>
> Thank you!
> Martin