From 81e8013484ae0790c7819aa9e08b265807eb6905 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 25 Jul 2013 16:07:39 -0700 Subject: [PATCH] staging: comedi: usbdux: fix usbdux_pwm_start() Add the missing down/up of the semaphore to prevent other commands from being issued to the usb device while the pwn is being stopped. Rename the local variable used for the private data pointer to the comedi "norm". Use memset() to initialize the urb transfer buffer. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbdux.c | 34 ++++++++++++------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c index 14c26e559cb7..0337da1f36fa 100644 --- a/drivers/staging/comedi/drivers/usbdux.c +++ b/drivers/staging/comedi/drivers/usbdux.c @@ -1544,34 +1544,34 @@ static int usbdux_pwm_period(struct comedi_device *dev, return 0; } -/* is called from insn so there's no need to do all the sanity checks */ static int usbdux_pwm_start(struct comedi_device *dev, struct comedi_subdevice *s) { - int ret, i; - struct usbdux_private *this_usbduxsub = dev->private; + struct usbdux_private *devpriv = dev->private; + int ret = 0; - if (this_usbduxsub->pwm_cmd_running) { - /* already running */ - return 0; - } + down(&devpriv->sem); + + if (devpriv->pwm_cmd_running) + goto pwm_start_exit; - this_usbduxsub->dux_commands[1] = ((int8_t) this_usbduxsub->pwn_delay); + devpriv->dux_commands[1] = devpriv->pwn_delay; ret = send_dux_commands(dev, SENDPWMON); if (ret < 0) - return ret; + goto pwm_start_exit; /* initialise the buffer */ - for (i = 0; i < this_usbduxsub->size_pwm_buf; i++) - ((char *)(this_usbduxsub->urb_pwm->transfer_buffer))[i] = 0; + memset(devpriv->urb_pwm->transfer_buffer, 0, devpriv->size_pwm_buf); - this_usbduxsub->pwm_cmd_running = 1; + devpriv->pwm_cmd_running = 1; ret = usbduxsub_submit_pwm_urbs(dev); - if (ret < 0) { - this_usbduxsub->pwm_cmd_running = 0; - return ret; - } - return 0; + if (ret < 0) + devpriv->pwm_cmd_running = 0; + +pwm_start_exit: + up(&devpriv->sem); + + return ret; } /* generates the bit pattern for PWM with the optional sign bit */ -- 2.30.2