[U-Boot] [PATCH 3/3] imx: mx6sllevk: add usb support

[Peng Fan]

> -----Original Message-----
> From: Marek Vasut [mailto:marex at denx.de]
> Sent: Thursday, December 22, 2016 3:12 PM
> To: Peng Fan <peng.fan at nxp.com>; sbabic at denx.de
> Cc: u-boot at lists.denx.de; van.freenix at gmail.com
> Subject: Re: [PATCH 3/3] imx: mx6sllevk: add usb support
> 
> On 12/22/2016 07:38 AM, Peng Fan wrote:
> >
> >
> >> -----Original Message-----
> >> From: Marek Vasut [mailto:marex at denx.de]
> >> Sent: Thursday, December 22, 2016 2:12 PM
> >> To: Peng Fan <peng.fan at nxp.com>; sbabic at denx.de
> >> Cc: u-boot at lists.denx.de; van.freenix at gmail.com
> >> Subject: Re: [PATCH 3/3] imx: mx6sllevk: add usb support
> >>
> >> On 12/22/2016 07:03 AM, Peng Fan wrote:
> >>>
> >>> Hi Marek,
> >>>
> >>>> -----Original Message-----
> >>>> From: Marek Vasut [mailto:marex at denx.de]
> >>>> Sent: Thursday, December 22, 2016 12:40 PM
> >>>> To: Peng Fan <peng.fan at nxp.com>; sbabic at denx.de
> >>>> Cc: u-boot at lists.denx.de; van.freenix at gmail.com
> >>>> Subject: Re: [PATCH 3/3] imx: mx6sllevk: add usb support
> >>>>
> >>>> On 12/22/2016 02:13 AM, Peng Fan wrote:
> >>>>>
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Marek Vasut [mailto:marex at denx.de]
> >>>>>> Sent: Wednesday, December 21, 2016 10:10 PM
> >>>>>> To: Peng Fan <peng.fan at nxp.com>; sbabic at denx.de
> >>>>>> Cc: u-boot at lists.denx.de; van.freenix at gmail.com
> >>>>>> Subject: Re: [PATCH 3/3] imx: mx6sllevk: add usb support
> >>>>>>
> >>>>>> On 12/21/2016 09:14 AM, Peng Fan wrote:
> >>>>>>> Add usb support for mx6sllevk board.
> >>>>>>>
> >>>>>>> Signed-off-by: Peng Fan <peng.fan at nxp.com>
> >>>>>>> Cc: Stefano Babic <sbabic at denx.de>
> >>>>>>> ---
> >>>>> [......]
> >>>>>
> >>>>>>> +
> >>>>>>> +#define USB_OTHERREGS_OFFSET   0x800
> >>>>>>> +#define UCTRL_PWR_POL          (1 << 9)
> >>>>>>> +
> >>>>>>> +int board_ehci_hcd_init(int port) {
> >>>>>>> +	u32 *usbnc_usb_ctrl;
> >>>>>>> +
> >>>>>>> +	if (port > 1)
> >>>>>>> +		return -EINVAL;
> >>>>>>> +
> >>>>>>> +	usbnc_usb_ctrl = (u32 *)(USB_BASE_ADDR +
> >> USB_OTHERREGS_OFFSET
> >>>>>> +
> >>>>>>> +				 port * 4);
> >>>>>>> +
> >>>>>>> +	/* Set Power polarity */
> >>>>>>> +	setbits_le32(usbnc_usb_ctrl, UCTRL_PWR_POL);
> >>>>>>> +	return 0;
> >>>>>>> +}
> >>>>>>
> >>>>>> Is this function similar to what usb_oc_config() does ?
> >>>>>
> >>>>> No, this bit is not for overcurrent. According to RM, this is OTG
> >>>>> Power Polarity This bit should be set according to power switch's
> >>>>> enable
> >>>> polarity.
> >>>>> 1 Power switch has an active-high enable input
> >>>>> 0 Power switch has an active-low enable input
> >>>>>
> >>>>> This is board specific.
> >>>>
> >>>> Great, except it should also be part of the driver , the same way
> >>>> as polarity is configured, yes ?
> >>>
> >>> I just found that there is code for mx7,
> >>> http://lists.denx.de/pipermail/u-boot/2016-July/260321.html
> >>>
> >>> Then do you agree I add such piece code in usb_power_config for mx6?
> >>> "
> >>> #ifdef CONFIG_MXC_USB_OTG_HACTIVE
> >>>         setbits_le32(ctrl, UCTRL_PWR_POL); #else
> >>>         clrbits_le32(ctrl, UCTRL_PWR_POL); #endif "
> >>
> >> Didn't you add DT support in a patch sent like ... yesterday ? :)
> >> Just use DT property instead of ifdef.
> >
> > There is no property for otg power polatiry in upstream Linux. I would
> > not like to introduce one in U-Boot. We can drop the ifdef when there is an
> property in upstream. What do you think?
> 
> So uh, how can the USB work in mainline Linux on that board ?

Confirmed with IC, if using gpio to control vbus power, no need to configure this bit.
Since in dts, we are using gpio regulator to control vbus, this piece code in patch 3/3
can be discarded. I'll drop it in V2.

Thanks,
Peng.

> 
> --
> Best regards,
> Marek Vasut