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Message-ID: <Pine.LNX.4.44L0.2003101003280.1651-100000@iolanthe.rowland.org>
Date: Tue, 10 Mar 2020 10:03:45 -0400 (EDT)
From: Alan Stern <stern@...land.harvard.edu>
To: Lubomir Rintel <lkundrak@...sk>
cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] USB: EHCI: ehci-mv: switch the HSIC HCI to HSIC mode
On Mon, 9 Mar 2020, Lubomir Rintel wrote:
> Turns out the undocumented and reserved bits of port status/control
> register of the root port need to be set to use the HCI in HSIC mode.
>
> Typically the firmware does this, but that is not always good enough,
> because the bits get lost if the HSIC clock is disabled (e.g. when
> ehci-mv is build as a module).
>
> This supplements commit 7b104f890ade ("USB: EHCI: ehci-mv: add HSIC
> support").
>
> Signed-off-by: Lubomir Rintel <lkundrak@...sk>
Acked-by: Alan Stern <stern@...land.harvard.edu>
> ---
> drivers/usb/host/ehci-mv.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/usb/host/ehci-mv.c b/drivers/usb/host/ehci-mv.c
> index bd4f6ef534d96..ddb668963955f 100644
> --- a/drivers/usb/host/ehci-mv.c
> +++ b/drivers/usb/host/ehci-mv.c
> @@ -110,6 +110,7 @@ static int mv_ehci_probe(struct platform_device *pdev)
> struct resource *r;
> int retval = -ENODEV;
> u32 offset;
> + u32 status;
>
> if (usb_disabled())
> return -ENODEV;
> @@ -213,6 +214,14 @@ static int mv_ehci_probe(struct platform_device *pdev)
> device_wakeup_enable(hcd->self.controller);
> }
>
> + if (of_usb_get_phy_mode(pdev->dev.of_node) == USBPHY_INTERFACE_MODE_HSIC) {
> + status = ehci_readl(ehci, &ehci->regs->port_status[0]);
> + /* These "reserved" bits actually enable HSIC mode. */
> + status |= BIT(25);
> + status &= ~GENMASK(31, 30);
> + ehci_writel(ehci, status, &ehci->regs->port_status[0]);
> + }
> +
> dev_info(&pdev->dev,
> "successful find EHCI device with regs 0x%p irq %d"
> " working in %s mode\n", hcd->regs, hcd->irq,
>
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