From 1265c22fc8575e857f0a0573db263b507988f420 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 29 Apr 2014 12:59:32 -0700 Subject: [PATCH] staging: comedi: das1800: don't calc pacer divisors twice The analog input async command can use the pacer for the scan_begin_src or the convert_src. The (*do_cmdtest) calculates the divisors when validating the cmd argument. There is no reason to recalc the divisors in the (*do_cmd). Just use the values from the private data. For aesthetics, rename the setup_counters() function so it has namespace associated with the driver. Refactor the function to use the values from the private data and absorb das1800_set_frequency() to clarify the code. Refactor the function to use the i8254_set_mode() and i8254_write() helpers instead of i8254_load(). This allows us to use the I8254_* defines when setting the mode to clarify the code. This function will not fail so change the return type to void to simplify the (*do_cmd) a bit. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/das1800.c | 76 +++++------------------- 1 file changed, 16 insertions(+), 60 deletions(-) diff --git a/drivers/staging/comedi/drivers/das1800.c b/drivers/staging/comedi/drivers/das1800.c index 93fd58b60e5c..ba357b6ec127 100644 --- a/drivers/staging/comedi/drivers/das1800.c +++ b/drivers/staging/comedi/drivers/das1800.c @@ -962,68 +962,29 @@ static int control_c_bits(const struct comedi_cmd *cmd) return control_c; } -/* loads counters with divisor1, divisor2 from private structure */ -static int das1800_set_frequency(struct comedi_device *dev) +static void das1800_setup_counters(struct comedi_device *dev, + const struct comedi_cmd *cmd) { struct das1800_private *devpriv = dev->private; - int err = 0; - - /* counter 1, mode 2 */ - if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 1, devpriv->divisor1, - 2)) - err++; - /* counter 2, mode 2 */ - if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 2, devpriv->divisor2, - 2)) - err++; - if (err) - return -1; + unsigned long timer_base = dev->iobase + DAS1800_COUNTER; - return 0; -} - -/* sets up counters */ -static int setup_counters(struct comedi_device *dev, - const struct comedi_cmd *cmd) -{ - struct das1800_private *devpriv = dev->private; - unsigned int period; + /* setup cascaded counters for conversion/scan frequency */ + if ((cmd->scan_begin_src == TRIG_FOLLOW || + cmd->scan_begin_src == TRIG_TIMER) && + cmd->convert_src == TRIG_TIMER) { + i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY); + i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY); - /* setup cascaded counters for conversion/scan frequency */ - switch (cmd->scan_begin_src) { - case TRIG_FOLLOW: /* not in burst mode */ - if (cmd->convert_src == TRIG_TIMER) { - /* set conversion frequency */ - period = cmd->convert_arg; - i8253_cascade_ns_to_timer(I8254_OSC_BASE_5MHZ, - &devpriv->divisor1, - &devpriv->divisor2, - &period, cmd->flags); - if (das1800_set_frequency(dev) < 0) - return -1; - } - break; - case TRIG_TIMER: /* in burst mode */ - /* set scan frequency */ - period = cmd->scan_begin_arg; - i8253_cascade_ns_to_timer(I8254_OSC_BASE_5MHZ, - &devpriv->divisor1, - &devpriv->divisor2, - &period, cmd->flags); - if (das1800_set_frequency(dev) < 0) - return -1; - break; - default: - break; + i8254_write(timer_base, 0, 1, devpriv->divisor1); + i8254_write(timer_base, 0, 2, devpriv->divisor2); } - /* setup counter 0 for 'about triggering' */ + /* setup counter 0 for 'about triggering' */ if (cmd->stop_src == TRIG_EXT) { - /* load counter 0 in mode 0 */ - i8254_load(dev->iobase + DAS1800_COUNTER, 0, 0, 1, 0); - } + i8254_set_mode(timer_base, 0, 0, I8254_MODE0 | I8254_BINARY); - return 0; + i8254_write(timer_base, 0, 0, 1); + } } /* utility function that suggests a dma transfer size based on the conversion period 'ns' */ @@ -1136,7 +1097,6 @@ static int das1800_ai_do_cmd(struct comedi_device *dev, struct comedi_subdevice *s) { struct das1800_private *devpriv = dev->private; - int ret; int control_a, control_c; struct comedi_async *async = s->async; const struct comedi_cmd *cmd = &async->cmd; @@ -1167,11 +1127,7 @@ static int das1800_ai_do_cmd(struct comedi_device *dev, /* setup card and start */ program_chanlist(dev, cmd); - ret = setup_counters(dev, cmd); - if (ret < 0) { - comedi_error(dev, "Error setting up counters"); - return ret; - } + das1800_setup_counters(dev, cmd); setup_dma(dev, cmd); outb(control_c, dev->iobase + DAS1800_CONTROL_C); /* set conversion rate and length for burst mode */ -- 2.39.2