linux-kernel - Re: [PATCH v2] mx8mm: usb: chipidea: Fix Battery Charger 1.2 CDP detection

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Message-ID: <CAC4tdFXrGmmgui2uc-K2sgzxsgsQhQoARwO0720_wFb2ehpJ1A@mail.gmail.com>
Date:   Sat, 12 Jun 2021 13:59:21 -0400
From:   Breno Matheus Lima <brenomatheus@...il.com>
To:     Peter Chen <peter.chen@...nel.org>
Cc:     Breno Lima <breno.lima@....com>, gregkh@...uxfoundation.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        Fabio Estevam <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Jun Li <jun.li@....com>
Subject: Re: [PATCH v2] mx8mm: usb: chipidea: Fix Battery Charger 1.2 CDP detection

Hi Peter,

Em sáb., 12 de jun. de 2021 às 03:24, Peter Chen
<peter.chen@...nel.org> escreveu:
>
> On 21-06-11 10:56:07, Breno Lima wrote:
> > i.MX8MM cannot detect certain CDP USB HUBs. usbmisc_imx.c driver is not
> > following CDP timing requirements defined by USB BC 1.2 specification
> > and section 3.2.4 Detection Timing CDP.
> >
> > During Primary Detection the i.MX device should turn on VDP_SRC and
> > IDM_SINK for a minimum of 40ms (TVDPSRC_ON). After a time of TVDPSRC_ON,
> > the PD is allowed to check the status of the D- line. Current
> > implementation is waiting between 1ms and 2ms, and certain BC 1.2
> > complaint USB HUBs cannot be detected. Increase delay to 40ms allowing
> > enough time for primary detection.
> >
> > During secondary detection the PD is required to disable VDP_SRC and
>
> What does the "PD" mean here?
>

PD stands for Portable Device, I can send another version and mention
i.MX instead.

Thanks for pointing this out.

Best regards,
Breno Lima