On Sun, 18 Jan 2015 15:51:21 +0100
Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx> wrote:
> Prepare_enable on rising edge, disable_unprepare on falling edge. Reduce
> power consumption if USB PLL is not already necessary for OHCI or EHCI.
> If USB host is not connected we can sleep with USB PLL stopped.
>
> This driver does not support suspend/resume yet, not suspending if we
> are still attached to an USB host is fine for what I need, this patch
> allow suspending with USB PLL stopped when USB device is not currently
> used.
>
> Signed-off-by: Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx>
> ---
> drivers/usb/gadget/udc/atmel_usba_udc.c | 95 ++++++++++++++++++++++++---------
> drivers/usb/gadget/udc/atmel_usba_udc.h | 4 ++
> 2 files changed, 73 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
> index e207d75..986677b 100644
> --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> @@ -315,6 +315,38 @@ static inline void usba_cleanup_debugfs(struct usba_udc *udc)
> }
> #endif
>
> +static int start_clock(struct usba_udc *udc)
> +{
> + int ret;
> +
> + if (udc->clocked)
> + return 0;
> +
> + ret = clk_prepare_enable(udc->pclk);
> + if (ret)
> + return ret;
> + ret = clk_prepare_enable(udc->hclk);
> + if (ret) {
> + clk_disable_unprepare(udc->pclk);
> + return ret;
> + }
> +
> + udc->clocked = true;
> + return ret;
> +}
> +
> +static int stop_clock(struct usba_udc *udc)
> +{
> + if (!udc->clocked)
> + return 0;
> +
> + clk_disable_unprepare(udc->hclk);
> + clk_disable_unprepare(udc->pclk);
> +
> + udc->clocked = false;
> + return 0;
> +}
> +
> static int vbus_is_present(struct usba_udc *udc)
> {
> if (gpio_is_valid(udc->vbus_pin))
> @@ -1719,42 +1751,55 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
> return IRQ_HANDLED;
> }
>
> -static irqreturn_t usba_vbus_irq(int irq, void *devid)
> +static irqreturn_t usba_vbus_irq_thread(int irq, void *devid)
> {
> struct usba_udc *udc = devid;
> int vbus;
> + int ret;
>
> /* debounce */
> udelay(10);
>
> - spin_lock(&udc->lock);
> + mutex_lock(&udc->vbus_mutex);
>
> /* May happen if Vbus pin toggles during probe() */
> - if (!udc->driver)
> + spin_lock(&udc->lock);
Since this lock is taken in irq context (usba_udc_irq) and this
handler is not called in irq context anymore you should use
spin_lock_irqsave/unlock_irqrestore here.
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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