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

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Date:   Sat, 12 Jun 2021 15:24:38 +0800
From:   Peter Chen <peter.chen@...nel.org>
To:     Breno Lima <breno.lima@....com>
Cc:     gregkh@...uxfoundation.org, shawnguo@...nel.org,
        s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
        linux-imx@....com, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        brenomatheus@...il.com, jun.li@....com
Subject: Re: [PATCH v2] mx8mm: usb: chipidea: Fix Battery Charger 1.2 CDP
 detection

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?

> IDM_SNK, and enable VDM_SRC and IDP_SINK for at least 40ms (TVDMSRC_ON).
> 
> Current implementation is not disabling VDP_SRC and IDM_SNK, introduce
> disable sequence in imx7d_charger_secondary_detection() function.
> 
> VDM_SRC and IDP_SINK should be enabled for at least 40ms (TVDMSRC_ON).
> Increase delay allowing enough time for detection.
> 
> Fixes: 746f316b753a ("usb: chipidea: introduce imx7d USB charger detection")

I assume this one needs to go stable tree?

Peter
> 
> Signed-off-by: Breno Lima <breno.lima@....com>
> Signed-off-by: Jun Li <jun.li@....com>
> ---
> Changes since V1:
> - Updated commit log to include commit ID fix
>  drivers/usb/chipidea/usbmisc_imx.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/usbmisc_imx.c b/drivers/usb/chipidea/usbmisc_imx.c
> index 4545b23bda3f..bac0f5458cab 100644
> --- a/drivers/usb/chipidea/usbmisc_imx.c
> +++ b/drivers/usb/chipidea/usbmisc_imx.c
> @@ -686,6 +686,16 @@ static int imx7d_charger_secondary_detection(struct imx_usbmisc_data *data)
>  	int val;
>  	unsigned long flags;
>  
> +	/* Clear VDATSRCENB0 to disable VDP_SRC and IDM_SNK required by BC 1.2 spec */
> +	spin_lock_irqsave(&usbmisc->lock, flags);
> +	val = readl(usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
> +	val &= ~MX7D_USB_OTG_PHY_CFG2_CHRG_VDATSRCENB0;
> +	writel(val, usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
> +	spin_unlock_irqrestore(&usbmisc->lock, flags);
> +
> +	/* TVDMSRC_DIS */
> +	msleep(20);
> +
>  	/* VDM_SRC is connected to D- and IDP_SINK is connected to D+ */
>  	spin_lock_irqsave(&usbmisc->lock, flags);
>  	val = readl(usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
> @@ -695,7 +705,8 @@ static int imx7d_charger_secondary_detection(struct imx_usbmisc_data *data)
>  				usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
>  	spin_unlock_irqrestore(&usbmisc->lock, flags);
>  
> -	usleep_range(1000, 2000);
> +	/* TVDMSRC_ON */
> +	msleep(40);
>  
>  	/*
>  	 * Per BC 1.2, check voltage of D+:
> @@ -798,7 +809,8 @@ static int imx7d_charger_primary_detection(struct imx_usbmisc_data *data)
>  				usbmisc->base + MX7D_USB_OTG_PHY_CFG2);
>  	spin_unlock_irqrestore(&usbmisc->lock, flags);
>  
> -	usleep_range(1000, 2000);
> +	/* TVDPSRC_ON */
> +	msleep(40);
>  
>  	/* Check if D- is less than VDAT_REF to determine an SDP per BC 1.2 */
>  	val = readl(usbmisc->base + MX7D_USB_OTG_PHY_STATUS);
> -- 
> 2.25.1
> 

-- 

Thanks,
Peter Chen