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Commit 82ed3381 authored by Dave Penkler's avatar Dave Penkler Committed by Greg Kroah-Hartman
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Add support for USBTMC USB488 SRQ notification with fasync 



Background:
By configuring an instrument's event status register various
conditions can be reported via an SRQ notification. This complements
the synchronous polling approach using the READ_STATUS_BYTE ioctl
with an asynchronous notification.

Signed-off-by: default avatarDave Penkler <dpenkler@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dbf3e7f6

drivers/usb/class/usbtmc.c

+24 −0
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ struct usbtmc_device_data { 
	int            iin_interval;

	struct urb    *iin_urb;

	u16            iin_wMaxPacketSize;

	atomic_t       srq_asserted;



	u8 rigol_quirk;
@@ -113,6 +114,7 @@ struct usbtmc_device_data { 
	struct kref kref;

	struct mutex io_mutex;	/* only one i/o function running at a time */

	wait_queue_head_t waitq;

	struct fasync_struct *fasync;

};

#define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
@@ -405,6 +407,9 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_device_data *data, 


	atomic_set(&data->iin_data_valid, 0);



	/* must issue read_stb before using poll or select */

	atomic_set(&data->srq_asserted, 0);



	rv = usb_control_msg(data->usb_dev,

			usb_rcvctrlpipe(data->usb_dev, 0),

			USBTMC488_REQUEST_READ_STATUS_BYTE,
@@ -1172,6 +1177,13 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	return retval;

}



static int usbtmc_fasync(int fd, struct file *file, int on)

{

	struct usbtmc_device_data *data = file->private_data;



	return fasync_helper(fd, file, on, &data->fasync);

}



static const struct file_operations fops = {

	.owner		= THIS_MODULE,

	.read		= usbtmc_read,
@@ -1179,6 +1191,7 @@ static const struct file_operations fops = { 
	.open		= usbtmc_open,

	.release	= usbtmc_release,

	.unlocked_ioctl	= usbtmc_ioctl,

	.fasync         = usbtmc_fasync,

	.llseek		= default_llseek,

};
@@ -1208,6 +1221,16 @@ static void usbtmc_interrupt(struct urb *urb) 
			wake_up_interruptible(&data->waitq);

			goto exit;

		}

		/* check for SRQ notification */

		if (data->iin_buffer[0] == 0x81) {

			if (data->fasync)

				kill_fasync(&data->fasync,

					SIGIO, POLL_IN);



			atomic_set(&data->srq_asserted, 1);

			wake_up_interruptible(&data->waitq);

			goto exit;

		}

		dev_warn(dev, "invalid notification: %x\n", data->iin_buffer[0]);

		break;

	case -EOVERFLOW:
@@ -1263,6 +1286,7 @@ static int usbtmc_probe(struct usb_interface *intf, 
	mutex_init(&data->io_mutex);

	init_waitqueue_head(&data->waitq);

	atomic_set(&data->iin_data_valid, 0);

	atomic_set(&data->srq_asserted, 0);

	data->zombie = 0;



	/* Determine if it is a Rigol or not */