[PATCH RFC] usb: chipidea: imx: make over-current polarity configurable for i.MX25

[Peter Chen]

On Tue, Oct 24, 2017 at 10:57:29AM +0200, Uwe Kleine-König wrote:
> In commit 9dba516ed282 ("usb: chipidea: imx: set over current polarity
> per dts setting") i.MX6 and i.MX7 learned the dt property
> "over-current-active-high". The difference compared to i.MX25 is that on
> the latter the default in hardware and the driver is already
> active-high. For that reason the over-current-active-high property is
> added to the imx25 template to keep the default behaviour.
> 
> The obvious downside is that device trees that were compiled before this
> change don't have that property and so when run with a kernel including
> this change suddenly use active low logic. This could only be
> circumvented with another property "over-current-active-low" and
> different default handling for imx6/7 vs imx25 if none (or both) of the
> properties are present. For simplicity I stick to the easier and better
> understandable alternative at the cost of dt incompatibility.

Sorry to reply late, in order to keep compatibility, my suggestion is
add another property "over-current-active-low" and change imx25 related
code accordingly.

Peter
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> ---
> Hello,
> 
> is it ok to break compatibility here?
> 
> Best regards
> Uwe
> 
>  arch/arm/boot/dts/imx25.dtsi       |  2 ++
>  drivers/usb/chipidea/usbmisc_imx.c | 15 +++++++++++++--
>  2 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx25.dtsi b/arch/arm/boot/dts/imx25.dtsi
> index 09ce8b81fafa..bb0054603846 100644
> --- a/arch/arm/boot/dts/imx25.dtsi
> +++ b/arch/arm/boot/dts/imx25.dtsi
> @@ -565,6 +565,7 @@
>  				fsl,usbphy = <&usbphy0>;
>  				phy_type = "utmi";
>  				dr_mode = "otg";
> +				over-current-active-high;
>  				status = "disabled";
>  			};
>  
> @@ -576,6 +577,7 @@
>  				clock-names = "ipg", "ahb", "per";
>  				fsl,usbmisc = <&usbmisc 1>;
>  				fsl,usbphy = <&usbphy1>;
> +				over-current-active-high;
>  				status = "disabled";
>  			};
>  
> diff --git a/drivers/usb/chipidea/usbmisc_imx.c b/drivers/usb/chipidea/usbmisc_imx.c
> index 9f4a0185dd60..6f3d0341357c 100644
> --- a/drivers/usb/chipidea/usbmisc_imx.c
> +++ b/drivers/usb/chipidea/usbmisc_imx.c
> @@ -125,16 +125,27 @@ static int usbmisc_imx25_init(struct imx_usbmisc_data *data)
>  		val = readl(usbmisc->base);
>  		val &= ~(MX25_OTG_SIC_MASK | MX25_OTG_PP_BIT);
>  		val |= (MX25_EHCI_INTERFACE_DIFF_UNI & MX25_EHCI_INTERFACE_MASK) << MX25_OTG_SIC_SHIFT;
> -		val |= (MX25_OTG_PM_BIT | MX25_OTG_OCPOL_BIT);
> +		val |= MX25_OTG_PM_BIT;
> +
> +		if (data->oc_polarity)
> +			val |= MX25_OTG_OCPOL_BIT;
> +		else
> +			val &= ~MX25_OTG_OCPOL_BIT;
> +
>  		writel(val, usbmisc->base);
>  		break;
>  	case 1:
>  		val = readl(usbmisc->base);
>  		val &= ~(MX25_H1_SIC_MASK | MX25_H1_PP_BIT |  MX25_H1_IPPUE_UP_BIT);
>  		val |= (MX25_EHCI_INTERFACE_SINGLE_UNI & MX25_EHCI_INTERFACE_MASK) << MX25_H1_SIC_SHIFT;
> -		val |= (MX25_H1_PM_BIT | MX25_H1_OCPOL_BIT | MX25_H1_TLL_BIT |
> +		val |= (MX25_H1_PM_BIT | MX25_H1_TLL_BIT |
>  			MX25_H1_USBTE_BIT | MX25_H1_IPPUE_DOWN_BIT);
>  
> +		if (data->oc_polarity)
> +			val |= MX25_H1_OCPOL_BIT;
> +		else
> +			val &= ~MX25_H1_OCPOL_BIT;
> +
>  		writel(val, usbmisc->base);
>  
>  		break;
> -- 
> 2.11.0
> 
> 
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-- 

Best Regards,
Peter Chen