linux-kernel - Re: [PATCH] usb: dwc2: disable erroneous overcurrent condition

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Date:   Mon, 16 Oct 2017 18:37:49 +0200
From:   Marek Vasut <marex@...x.de>
To:     Dinh Nguyen <dinguyen@...nel.org>, johnyoun@...opsys.com
Cc:     balbi@...nel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] usb: dwc2: disable erroneous overcurrent condition

On 10/16/2017 03:57 PM, Dinh Nguyen wrote:
> For the case where an external VBUS is used, we should enable the external
> VBUS comparator in the driver. This would prevent an unnecessary
> overcurrent error which would then disable the host port.
> 
> This patch uses the standard 'disable-over-current' binding to allow of the
> option of disabling the over-current condition.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@...nel.org>

Reviewed-by: Marek Vasut <marex@...x.de>

Similar patch was in U-Boot for two years now and it does the trick indeed.

> ---
>  drivers/usb/dwc2/core.h   | 4 ++++
>  drivers/usb/dwc2/hcd.c    | 5 +++++
>  drivers/usb/dwc2/params.c | 3 +++
>  3 files changed, 12 insertions(+)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 8367d4f9..730d7eb 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -395,6 +395,9 @@ enum dwc2_ep0_state {
>   *                           (default when phy_type is UTMI+ or ULPI)
>   *                       1 - 6 MHz
>   *                           (default when phy_type is Full Speed)
> + * @oc_disable:		Flag to disable overcurrent condition.
> + *			0 - Allow overcurrent condition to get detected
> + *			1 - Disable overcurrent condtion to get detected
>   * @ts_dline:           Enable Term Select Dline pulsing
>   *                       0 - No (default)
>   *                       1 - Yes
> @@ -492,6 +495,7 @@ struct dwc2_core_params {
>  	bool dma_desc_fs_enable;
>  	bool host_support_fs_ls_low_power;
>  	bool host_ls_low_power_phy_clk;
> +	bool oc_disable;
>  
>  	u8 host_channels;
>  	u16 host_rx_fifo_size;
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index c263114..5e20336 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -213,6 +213,11 @@ static int dwc2_hs_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
>  		usbcfg &= ~(GUSBCFG_PHYIF16 | GUSBCFG_DDRSEL);
>  		if (hsotg->params.phy_ulpi_ddr)
>  			usbcfg |= GUSBCFG_DDRSEL;
> +
> +		/* Set external VBUS indicator as needed. */
> +		if (hsotg->params.oc_disable)
> +			usbcfg |= (GUSBCFG_ULPI_INT_VBUS_IND |
> +				   GUSBCFG_INDICATORPASSTHROUGH);
>  		break;
>  	case DWC2_PHY_TYPE_PARAM_UTMI:
>  		/* UTMI+ interface */
> diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
> index a3ffe97..39e02cd 100644
> --- a/drivers/usb/dwc2/params.c
> +++ b/drivers/usb/dwc2/params.c
> @@ -335,6 +335,9 @@ static void dwc2_get_device_properties(struct dwc2_hsotg *hsotg)
>  						       num);
>  		}
>  	}
> +
> +	if (of_find_property(hsotg->dev->of_node, "disable-over-current", NULL))
> +		p->oc_disable = true;
>  }
>  
>  static void dwc2_check_param_otg_cap(struct dwc2_hsotg *hsotg)
> 


-- 
Best regards,
Marek Vasut