[PATCH 2/3] at91_udc: Add vbus polarity and polling mode
Nicolas Ferre
nicolas.ferre at atmel.com
Tue Jul 6 04:32:40 EDT 2010
Le 02/07/2010 06:40, Ryan Mallon :
> On 07/02/2010 01:45 AM, Nicolas Ferre wrote:
>> Le 28/06/2010 06:39, Ryan Mallon :
>>
>>> Allow the vbus signal to optionally use polling. This is required if
>>> the vbus signal is connected to an non-interrupting io expander for
>>> example. If vbus is in polling mode, then it is assumed that the vbus
>>> gpio may sleep. Also add an option to have vbus be an active low
>>> signal. Both options are set in the platform data for the device.
>>>
>>> Signed-off-by: Ryan Mallon <ryan at bluewatersys.com>
>>>
>> Looks good, but... one question:
>>
>>
>>> @@ -1763,13 +1793,22 @@ static int __init at91udc_probe(struct platform_device *pdev)
>>> * Get the initial state of VBUS - we cannot expect
>>> * a pending interrupt.
>>> */
>>> - udc->vbus = gpio_get_value(udc->board.vbus_pin);
>>> - if (request_irq(udc->board.vbus_pin, at91_vbus_irq,
>>> - IRQF_DISABLED, driver_name, udc)) {
>>> - DBG("request vbus irq %d failed\n",
>>> - udc->board.vbus_pin);
>>> - retval = -EBUSY;
>>> - goto fail3;
>>> + if (udc->board.vbus_polled) {
>>> + udc->vbus = gpio_get_value_cansleep(udc->board.vbus_pin);
>>>
>> Shouldn't we need here something like:
>> udc->vbus = (udc->board.vbus_active_low) ^ gpio_get_value_cansleep(udc->board.vbus_pin);
>>
>
> Yes, thanks. The updated patch below fixes it. Also simplify
> at91_vbus_update (always do the xor) and move the initial setting of
> udc->vbus outside of the udc->board.vbus_polled test, since we can use
> gpio_get_value_cansleep in both cases.
>
> Signed-off-by: Ryan Mallon <ryan at bluewatersys.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
> ---
>
> diff --git a/arch/arm/mach-at91/include/mach/board.h b/arch/arm/mach-at91/include/mach/board.h
> index df2ed84..58528aa 100644
> --- a/arch/arm/mach-at91/include/mach/board.h
> +++ b/arch/arm/mach-at91/include/mach/board.h
> @@ -44,6 +44,8 @@
> /* USB Device */
> struct at91_udc_data {
> u8 vbus_pin; /* high == host powering us */
> + u8 vbus_active_low; /* vbus polarity */
> + u8 vbus_polled; /* Use polling, not interrupt */
> u8 pullup_pin; /* active == D+ pulled up */
> u8 pullup_active_low; /* true == pullup_pin is active low */
> };
> diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
> index eaa79c8..be36f2f 100644
> --- a/drivers/usb/gadget/at91_udc.c
> +++ b/drivers/usb/gadget/at91_udc.c
> @@ -76,6 +76,7 @@
> static const char driver_name [] = "at91_udc";
> static const char ep0name[] = "ep0";
>
> +#define VBUS_POLL_TIMEOUT msecs_to_jiffies(1000)
>
> #define at91_udp_read(dev, reg) \
> __raw_readl((dev)->udp_baseaddr + (reg))
> @@ -1556,20 +1557,48 @@ static struct at91_udc controller = {
> /* ep6 and ep7 are also reserved (custom silicon might use them) */
> };
>
> +static void at91_vbus_update(struct at91_udc *udc, unsigned value)
> +{
> + value ^= udc->board.vbus_active_low;
> + if (value != udc->vbus)
> + at91_vbus_session(&udc->gadget, value);
> +}
> +
> static irqreturn_t at91_vbus_irq(int irq, void *_udc)
> {
> struct at91_udc *udc = _udc;
> - unsigned value;
>
> /* vbus needs at least brief debouncing */
> udelay(10);
> - value = gpio_get_value(udc->board.vbus_pin);
> - if (value != udc->vbus)
> - at91_vbus_session(&udc->gadget, value);
> + at91_vbus_update(udc, gpio_get_value(udc->board.vbus_pin));
>
> return IRQ_HANDLED;
> }
>
> +static void at91_vbus_timer_work(struct work_struct *work)
> +{
> + struct at91_udc *udc = container_of(work, struct at91_udc,
> + vbus_timer_work);
> +
> + at91_vbus_update(udc, gpio_get_value_cansleep(udc->board.vbus_pin));
> +
> + if (!timer_pending(&udc->vbus_timer))
> + mod_timer(&udc->vbus_timer, jiffies + VBUS_POLL_TIMEOUT);
> +}
> +
> +static void at91_vbus_timer(unsigned long data)
> +{
> + struct at91_udc *udc = (struct at91_udc *)data;
> +
> + /*
> + * If we are polling vbus it is likely that the gpio is on an
> + * bus such as i2c or spi which may sleep, so schedule some work
> + * to read the vbus gpio
> + */
> + if (!work_pending(&udc->vbus_timer_work))
> + schedule_work(&udc->vbus_timer_work);
> +}
> +
> int usb_gadget_register_driver (struct usb_gadget_driver *driver)
> {
> struct at91_udc *udc = &controller;
> @@ -1763,13 +1792,23 @@ static int __init at91udc_probe(struct platform_device *pdev)
> * Get the initial state of VBUS - we cannot expect
> * a pending interrupt.
> */
> - udc->vbus = gpio_get_value(udc->board.vbus_pin);
> - if (request_irq(udc->board.vbus_pin, at91_vbus_irq,
> - IRQF_DISABLED, driver_name, udc)) {
> - DBG("request vbus irq %d failed\n",
> - udc->board.vbus_pin);
> - retval = -EBUSY;
> - goto fail3;
> + udc->vbus = gpio_get_value_cansleep(udc->board.vbus_pin) ^
> + udc->board.vbus_active_low;
> +
> + if (udc->board.vbus_polled) {
> + INIT_WORK(&udc->vbus_timer_work, at91_vbus_timer_work);
> + setup_timer(&udc->vbus_timer, at91_vbus_timer,
> + (unsigned long)udc);
> + mod_timer(&udc->vbus_timer,
> + jiffies + VBUS_POLL_TIMEOUT);
> + } else {
> + if (request_irq(udc->board.vbus_pin, at91_vbus_irq,
> + IRQF_DISABLED, driver_name, udc)) {
> + DBG("request vbus irq %d failed\n",
> + udc->board.vbus_pin);
> + retval = -EBUSY;
> + goto fail3;
> + }
> }
> } else {
> DBG("no VBUS detection, assuming always-on\n");
> @@ -1855,7 +1894,7 @@ static int at91udc_suspend(struct platform_device *pdev, pm_message_t mesg)
> enable_irq_wake(udc->udp_irq);
>
> udc->active_suspend = wake;
> - if (udc->board.vbus_pin > 0 && wake)
> + if (udc->board.vbus_pin > 0 && !udc->board.vbus_polled && wake)
> enable_irq_wake(udc->board.vbus_pin);
> return 0;
> }
> @@ -1864,7 +1903,8 @@ static int at91udc_resume(struct platform_device *pdev)
> {
> struct at91_udc *udc = platform_get_drvdata(pdev);
>
> - if (udc->board.vbus_pin > 0 && udc->active_suspend)
> + if (udc->board.vbus_pin > 0 && !udc->board.vbus_polled &&
> + udc->active_suspend)
> disable_irq_wake(udc->board.vbus_pin);
>
> /* maybe reconnect to host; if so, clocks on */
> diff --git a/drivers/usb/gadget/at91_udc.h b/drivers/usb/gadget/at91_udc.h
> index c65d622..a1f4f54 100644
> --- a/drivers/usb/gadget/at91_udc.h
> +++ b/drivers/usb/gadget/at91_udc.h
> @@ -144,6 +144,8 @@ struct at91_udc {
> struct proc_dir_entry *pde;
> void __iomem *udp_baseaddr;
> int udp_irq;
> + struct timer_list vbus_timer;
> + struct work_struct vbus_timer_work;
> };
>
> static inline struct at91_udc *to_udc(struct usb_gadget *g)
>
>
>
>
--
Nicolas Ferre
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