From 57befc33af0243e9b3835d46ab836406256f5dd4 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Thu, 23 Jul 2015 16:47:01 +0100 Subject: [PATCH] staging: comedi: usbduxsigma: remove unused "convert" timing for AO The `cmdtest` and `cmd` handlers for the AO subdevice (`usbduxsigma_ao_cmdtest()` and `usbduxsigma_ao_cmd()`) support "scan" timing of commands with all channels updated every "scan" period. There is some disabled code to use "convert" timing in high speed mode. That would allow channels to be updated sequentially every "convert" period. Since that code is incomplete and currently disabled, remove it to simplify the existing code. Signed-off-by: Ian Abbott Reviewed-by: Bernd Porr Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbduxsigma.c | 58 ++++++++-------------------- 1 file changed, 17 insertions(+), 41 deletions(-) diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c index 535cf01b..9f43e01 100644 --- a/drivers/staging/comedi/drivers/usbduxsigma.c +++ b/drivers/staging/comedi/drivers/usbduxsigma.c @@ -840,28 +840,20 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev, { struct usbduxsigma_private *devpriv = dev->private; int err = 0; - int high_speed; - unsigned int flags; - - /* high speed conversions are not used yet */ - high_speed = 0; /* (devpriv->high_speed) */ /* Step 1 : check if triggers are trivially valid */ err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_INT); - if (high_speed) { - /* - * start immediately a new scan - * the sampling rate is set by the coversion rate - */ - flags = TRIG_FOLLOW; - } else { - /* start a new scan (output at once) with a timer */ - flags = TRIG_TIMER; - } - err |= comedi_check_trigger_src(&cmd->scan_begin_src, flags); - + /* + * For now, always use "scan" timing with all channels updated at once + * (cmd->scan_begin_src == TRIG_TIMER, cmd->convert_src == TRIG_NOW). + * + * In a future version, "convert" timing with channels updated + * indivually may be supported in high speed mode + * (cmd->scan_begin_src == TRIG_FOLLOW, cmd->convert_src == TRIG_TIMER). + */ + err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER); err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_NOW); err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT); err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE); @@ -885,17 +877,7 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev, err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0); - if (cmd->scan_begin_src == TRIG_FOLLOW) /* internal trigger */ - err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0); - - if (cmd->scan_begin_src == TRIG_TIMER) { - err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg, - 1000000); - } - - /* not used now, is for later use */ - if (cmd->convert_src == TRIG_TIMER) - err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 125000); + err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg, 1000000); err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); @@ -920,19 +902,13 @@ static int usbduxsigma_ao_cmd(struct comedi_device *dev, down(&devpriv->sem); - if (cmd->convert_src == TRIG_TIMER) { - /* - * timing of the conversion itself: every 125 us - * at high speed (not used yet) - */ - devpriv->ao_timer = cmd->convert_arg / 125000; - } else { - /* - * timing of the scan: every 1ms - * we get all channels at once - */ - devpriv->ao_timer = cmd->scan_begin_arg / 1000000; - } + /* + * For now, only "scan" timing is supported. A future version may + * support "convert" timing in high speed mode. + * + * Timing of the scan: every 1ms all channels updated at once. + */ + devpriv->ao_timer = cmd->scan_begin_arg / 1000000; devpriv->ao_counter = devpriv->ao_timer; -- 2.7.4