linux-kernel - Re: [PATCH v4 2/2] usb: dwc2: add 'mode' which based on Kconfig select or dts setting

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Date:	Wed, 6 Aug 2014 15:24:55 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Kever Yang <kever.yang@...k-chips.com>
Cc:	Paul Zimmerman <paulz@...opsys.com>,
	Heiko Stuebner <heiko@...ech.de>,
	Addy Ke <addy.ke@...k-chips.com>,
	Eddie Cai <cf@...k-chips.com>, Jianqun Xu <xjq@...k-chips.com>,
	Olof Johansson <olof@...om.net>,
	Sonny Rao <sonnyrao@...omium.org>, wulf <wulf@...k-chips.com>,
	lyz <lyz@...k-chips.com>, Jingoo Han <jg1.han@...sung.com>,
	han jiang <hj@...k-chips.com>,
	Tao Huang <huangtao@...k-chips.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Dinh Nguyen <dinguyen@...era.com>
Subject: Re: [PATCH v4 2/2] usb: dwc2: add 'mode' which based on Kconfig
 select or dts setting

Kever,

On Tue, Aug 5, 2014 at 6:01 PM, Kever Yang <kever.yang@...k-chips.com> wrote:
> According to the "dr_mode", the otg controller can work as
> device role and host role. Some boards always want to use host mode
> and some other boards want to use gadget mode. We use the dts setting
> to set dwc2's mode, rather than fixing it to whatever hardware says.
>
> Signed-off-by: Kever Yang <kever.yang@...k-chips.com>
> Acked-by: Paul Zimmerman <paulz@...opsys.com>
> ---
>
> Changes in v4:
> - From Doug's suggestion:
>  -- remove dr_mode init from Kconfig code
>  -- change the commit meesage
>
> Changes in v3:
> - fix the odd spacing in dwc2_hsotg struct
> - From Jingoo's suggestion:
>     change the commit message
> - add dr_mode init from Kconfig
>
> Changes in v2:
> - put spaces around '+' operator
> - expand the comment for dr_mode
> - handle dr_mode is USB_DR_MODE_OTG
>
>  drivers/usb/dwc2/core.c     | 18 ++++++++++++++++++
>  drivers/usb/dwc2/core.h     |  5 +++++
>  drivers/usb/dwc2/platform.c |  4 ++++
>  3 files changed, 27 insertions(+)

I think this patch still makes sense even though we don't have a
combined driver yet.  Perhaps Paul or Dihn can confirm.

We could potentially do something based on KConfig (like you did in
patch set #3), but it wouldn't really make sense to do that until
after Dihn's work lands.


> diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
> index 27d2c9b..738bec2 100644
> --- a/drivers/usb/dwc2/core.c
> +++ b/drivers/usb/dwc2/core.c
> @@ -118,6 +118,7 @@ static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
>  {
>         u32 greset;
>         int count = 0;
> +       u32 gusbcfg;
>
>         dev_vdbg(hsotg->dev, "%s()\n", __func__);
>
> @@ -148,6 +149,23 @@ static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
>                 }
>         } while (greset & GRSTCTL_CSFTRST);
>
> +       if (hsotg->dr_mode == USB_DR_MODE_HOST) {
> +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> +               gusbcfg &= ~GUSBCFG_FORCEDEVMODE;
> +               gusbcfg |= GUSBCFG_FORCEHOSTMODE;
> +               writel(gusbcfg, hsotg->regs + GUSBCFG);
> +       } else if (hsotg->dr_mode == USB_DR_MODE_PERIPHERAL) {
> +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> +               gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;
> +               gusbcfg |= GUSBCFG_FORCEDEVMODE;
> +               writel(gusbcfg, hsotg->regs + GUSBCFG);
> +       } else if (hsotg->dr_mode == USB_DR_MODE_OTG) {
> +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> +               gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;
> +               gusbcfg &= ~GUSBCFG_FORCEDEVMODE;
> +               writel(gusbcfg, hsotg->regs + GUSBCFG);

I think the third case here won't be too useful until the combined
driver, but it shouldn't hurt, right?


-Doug
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