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authorDave Penkler <dpenkler@gmail.com>2016-01-27 19:15:15 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-03 13:54:06 -0800
commit82ed33811d7214198e071b785ee34dbe99f82140 (patch)
treea6f9785025685aaa7328c5d9a64bb8181725472f /drivers/usb/class
parentdbf3e7f654c0f06a932b8fcafac78de9d0b81d68 (diff)
downloadlinux-82ed33811d7214198e071b785ee34dbe99f82140.tar.bz2
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: Dave Penkler <dpenkler@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class')
-rw-r--r--drivers/usb/class/usbtmc.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index c2eb6fe9f4c8..d77da2fd7b70 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -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 @@ skip_io_on_zombie:
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 */