From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406AbbKRIi0 (ORCPT ); Wed, 18 Nov 2015 03:38:26 -0500 Received: from mail-wm0-f44.google.com ([74.125.82.44]:34006 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754031AbbKRIiX (ORCPT ); Wed, 18 Nov 2015 03:38:23 -0500 Date: Wed, 18 Nov 2015 09:38:18 +0100 From: Dave Penkler To: gregkh@linuxfoundation.org Cc: peter.chen@freescale.com, teuniz@gmail.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 3/5] Add support for receiving USBTMC USB488 SRQ notifications via poll/select Message-ID: <20151118083818.GC1945@slacky> References: <20151118083216.GA1845@slacky> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151118083216.GA1845@slacky> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Background: In many situations operations on multiple instruments need to be synchronized. poll/select provide a convenient way of waiting on a number of different instruments and other peripherals simultaneously. Signed-off-by: Dave Penkler --- drivers/usb/class/usbtmc.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index a95a63d..6294a3c 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -1186,6 +1187,27 @@ static int usbtmc_fasync(int fd, struct file *file, int on) return fasync_helper(fd, file, on, &data->fasync); } +static unsigned int usbtmc_poll(struct file *file, poll_table *wait) +{ + struct usbtmc_device_data *data = file->private_data; + unsigned int mask; + + mutex_lock(&data->io_mutex); + + if (data->zombie) { + mask = POLLHUP | POLLERR; + goto no_poll; + } + + poll_wait(file, &data->waitq, wait); + + mask = (atomic_read(&data->srq_asserted)) ? POLLIN | POLLRDNORM : 0; + +no_poll: + mutex_unlock(&data->io_mutex); + return mask; +} + static const struct file_operations fops = { .owner = THIS_MODULE, .read = usbtmc_read, @@ -1194,6 +1216,7 @@ static const struct file_operations fops = { .release = usbtmc_release, .unlocked_ioctl = usbtmc_ioctl, .fasync = usbtmc_fasync, + .poll = usbtmc_poll, .llseek = default_llseek, }; -- 2.5.1