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?
> This suspend operation must be done before stopping the USB clock,
> resume after the USB clock enabled.
>
> Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
> ---
>
> 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.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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