[PATCH 2/3] at91_udc: Add vbus polarity and polling mode
Ryan Mallon
ryan at bluewatersys.com
Fri Jul 2 00:40:30 EDT 2010
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>
---
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)
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