diff options
author | Dave Penkler <dpenkler@gmail.com> | 2016-01-27 19:15:15 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-03 13:54:06 -0800 |
commit | 82ed33811d7214198e071b785ee34dbe99f82140 (patch) | |
tree | a6f9785025685aaa7328c5d9a64bb8181725472f /drivers/usb/class | |
parent | dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 (diff) | |
download | linux-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.c | 24 |
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 */ |