From c769f85e2740ebe7e4c726632fed52818640faba Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 25 Jul 2013 16:10:25 -0700 Subject: [PATCH] staging: comedi: usbdux: simplify initializing the ao urb transfer_buffer Remove the ugly casting of datap to the ao urb->transfer_buffer. The format of the data in the buffer is simply. [0] = # of channels to update (s->async->cmd.chanlist.len) [1] = lsb of value for 1st channel to update [2] = msb of value for 1st channel to update [3] = 1st channel to update (depvriv->dac_commands[0]) If more than 1 channel is to be updated they are simply added to the buffer: [4] = lsb of value for 2st channel to update [5] = msb of value for 2st channel to update [6] = 1st channel to update (depvriv->dac_commands[1]) etc. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbdux.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c index 1399305d739f..cb94964cc9ba 100644 --- a/drivers/staging/comedi/drivers/usbdux.c +++ b/drivers/staging/comedi/drivers/usbdux.c @@ -425,8 +425,10 @@ static void usbduxsub_ao_isoc_irq(struct urb *urb) struct comedi_device *dev = urb->context; struct comedi_subdevice *s = dev->write_subdev; struct usbdux_private *devpriv = dev->private; - int i, ret; int8_t *datap; + int len; + int ret; + int i; switch (urb->status) { case 0: @@ -484,9 +486,11 @@ static void usbduxsub_ao_isoc_irq(struct urb *urb) return; } } + /* transmit data to the USB bus */ - ((uint8_t *) (urb->transfer_buffer))[0] = - s->async->cmd.chanlist_len; + datap = urb->transfer_buffer; + len = s->async->cmd.chanlist_len; + *datap++ = len; for (i = 0; i < s->async->cmd.chanlist_len; i++) { unsigned int chan = devpriv->dac_commands[i]; short val; @@ -498,12 +502,9 @@ static void usbduxsub_ao_isoc_irq(struct urb *urb) COMEDI_CB_OVERFLOW); } /* pointer to the DA */ - datap = - (&(((int8_t *) urb->transfer_buffer)[i * 3 + 1])); - /* get the data from comedi */ - datap[0] = val; - datap[1] = val >> 8; - datap[2] = chan; + *datap++ = val & 0xff; + *datap++ = (val >> 8) & 0xff; + *datap++ = chan; devpriv->ao_readback[chan] = val; s->async->events |= COMEDI_CB_BLOCK; -- 2.11.0