> -----Original Message-----
> From: Alexandre Belloni [mailto:alexandre.bell...@free-electrons.com]
> Sent: 2016年5月12日 11:53
> To: Yang, Wenyou <wenyou.y...@atmel.com>
> Cc: Alan Stern <st...@rowland.harvard.edu>; Greg Kroah-Hartman
> <gre...@linuxfoundation.org>; Ferre, Nicolas <nicolas.fe...@atmel.com>;
> linux-...@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm-
> ker...@lists.infradead.org
> Subject: Re: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending
>
> Hi,
>
> On 12/05/2016 at 09:05:34 +0800, Wenyou Yang wrote :
> > In order to get lower consumption, as a workaround, suspend the USB
> > PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
> > Configuration Register while OHCI USB suspending.
> >
>
> Why is that a workaround?
Because if these bits is not set as this patch, there is 5mA current left
at VDDOSC rail during suspend. If apply this patch, this current will disappear.
So, I think it is a workaround.
>
> > This suspend operation must be done before stopping the USB clock,
> > resume after the USB clock enabled.
> >
> > Signed-off-by: Wenyou Yang <wenyou.y...@atmel.com>
> > ---
> >
> > drivers/usb/host/ohci-at91.c | 63
> > ++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 63 insertions(+)
> >
> > diff --git a/drivers/usb/host/ohci-at91.c
> > b/drivers/usb/host/ohci-at91.c index d177372..ce898e0 100644
> > --- a/drivers/usb/host/ohci-at91.c
> > +++ b/drivers/usb/host/ohci-at91.c
> > @@ -21,6 +21,8 @@
> > #include <linux/io.h>
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/regmap.h>
> > #include <linux/usb.h>
> > #include <linux/usb/hcd.h>
> >
> > @@ -51,6 +53,7 @@ struct ohci_at91_priv {
> > struct clk *hclk;
> > bool clocked;
> > bool wakeup; /* Saved wake-up state for resume */
> > + struct regmap *sfr_regmap;
> > };
> > /* interface and function clocks; sometimes also an AHB clock */
> >
> > @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device
> > *pdev)
> >
> >
> > /*--------------------------------------------------------------------
> > -----*/
> >
> > +struct regmap *at91_dt_syscon_sfr(void) {
> > + struct regmap *regmap;
> > +
> > + regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> > + if (IS_ERR(regmap))
> > + return NULL;
> > +
> > + return regmap;
> > +}
> > +
> > static void usb_hcd_at91_remove (struct usb_hcd *, struct
> > platform_device *);
> >
> > /* configure so an HC device and id are always provided */ @@ -197,6
> > +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
> > goto err;
> > }
> >
> > + ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> > +
> > board = hcd->self.controller->platform_data;
> > ohci = hcd_to_ohci(hcd);
> > ohci->num_ports = board->ports;
> > @@ -581,6 +597,49 @@ static int ohci_hcd_at91_drv_remove(struct
> platform_device *pdev)
> > return 0;
> > }
> >
> > +#define SFR_OHCIICR 0x10
> > +#define SFR_OHCIICR_SUSPEND_A BIT(8)
> > +#define SFR_OHCIICR_SUSPEND_B BIT(9)
> > +#define SFR_OHCIICR_SUSPEND_C BIT(10)
> > +
> > +#define SFR_OHCIICR_USB_SUSPEND (SFR_OHCIICR_SUSPEND_A | \
> > + SFR_OHCIICR_SUSPEND_B | \
> > + SFR_OHCIICR_SUSPEND_C)
> > +
>
> Those defines should go in a header file either in include/soc/at91 or in
> include/linux/mfd
>
> > +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable) {
> > + u32 regval;
> > + int ret;
> > +
> > + if (IS_ERR(regmap))
> > + return PTR_ERR(regmap);
> > +
> > + ret = regmap_read(regmap, SFR_OHCIICR, ®val);
> > + if (ret)
> > + return ret;
> > +
> > + if (enable)
> > + regval &= ~SFR_OHCIICR_USB_SUSPEND;
> > + else
> > + regval |= SFR_OHCIICR_USB_SUSPEND;
> > +
> > + regmap_write(regmap, SFR_OHCIICR, regval);
> > +
> > + regmap_read(regmap, SFR_OHCIICR, ®val);
> > +
> > + return 0;
> > +}
> > +
> > +static int ohci_at91_port_suspend(struct regmap *regmap) {
> > + return ohci_at91_port_ctrl(regmap, false); }
> > +
> > +static int ohci_at91_port_resume(struct regmap *regmap) {
> > + return ohci_at91_port_ctrl(regmap, true); }
> > +
> > static int __maybe_unused
> > ohci_hcd_at91_drv_suspend(struct device *dev) { @@ -618,6 +677,8 @@
> > ohci_hcd_at91_drv_suspend(struct device *dev)
> > ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
> > ohci->rh_state = OHCI_RH_HALTED;
> >
> > + ohci_at91_port_suspend(ohci_at91->sfr_regmap);
> > +
>
> The main issue I see here is that you will call that function for all SoCs
> and it will
> always fail unless it is running on a sama5d2. Maybe we could be smarter about
> that.
Can we use another compatible, such as "atmel,sama5d2-ohci" to differentiate
it?
Best Regards,
Wenyou Yang
