From f23068ec57acd6fb0bf4c69075072350a5ff849a Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Wed, 19 Feb 2014 10:11:23 -0700 Subject: [PATCH] staging: comedi: pcl816: don't calc the timer divisors twice The timer divisors are calculated in the (*do_cmdtest) before the (*do_cmd) is called by the comedi core. The extra sanity checks in the (*do_cmd) are not necessary, the values returned from i8253_cascade_ns_to_timer() will be greater than 1. Save the values in the private data so they don't need to be recalced. Refactor pcl816_start_pacer() to use the values from the private data. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcl816.c | 41 +++++++++++---------------------- 1 file changed, 13 insertions(+), 28 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c index cfda332..a8302da 100644 --- a/drivers/staging/comedi/drivers/pcl816.c +++ b/drivers/staging/comedi/drivers/pcl816.c @@ -125,6 +125,8 @@ struct pcl816_private { unsigned int ai_act_chanlist_len; /* how long is actual MUX list */ unsigned int ai_act_chanlist_pos; /* actual position in MUX list */ unsigned int ai_poll_ptr; /* how many sampes transfer poll */ + unsigned int divisor1; + unsigned int divisor2; }; /* @@ -139,9 +141,9 @@ static void setup_channel_list(struct comedi_device *dev, static int pcl816_ai_cancel(struct comedi_device *dev, struct comedi_subdevice *s); -static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters, - unsigned int divisor1, unsigned int divisor2) +static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters) { + struct pcl816_private *devpriv = dev->private; unsigned long timer_base = dev->iobase + PCL816_TIMER_BASE; i8254_set_mode(timer_base, 0, 0, I8254_MODE1 | I8254_BINARY); @@ -153,8 +155,8 @@ static void pcl816_start_pacer(struct comedi_device *dev, bool load_counters, udelay(1); if (load_counters) { - i8254_write(timer_base, 0, 2, divisor2); - i8254_write(timer_base, 0, 1, divisor1); + i8254_write(timer_base, 0, 2, devpriv->divisor2); + i8254_write(timer_base, 0, 1, devpriv->divisor1); } } @@ -399,8 +401,9 @@ static irqreturn_t interrupt_pcl816(int irq, void *d) static int pcl816_ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_cmd *cmd) { + struct pcl816_private *devpriv = dev->private; int err = 0; - int tmp, divisor1 = 0, divisor2 = 0; + int tmp; /* Step 1 : check if triggers are trivially valid */ @@ -449,7 +452,8 @@ static int pcl816_ai_cmdtest(struct comedi_device *dev, if (cmd->convert_src == TRIG_TIMER) { tmp = cmd->convert_arg; i8253_cascade_ns_to_timer(I8254_OSC_BASE_10MHZ, - &divisor1, &divisor2, + &devpriv->divisor1, + &devpriv->divisor2, &cmd->convert_arg, cmd->flags); if (cmd->convert_arg < 10000) cmd->convert_arg = 10000; @@ -475,33 +479,14 @@ static int pcl816_ai_cmdtest(struct comedi_device *dev, static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) { struct pcl816_private *devpriv = dev->private; - unsigned int divisor1 = 0, divisor2 = 0, dma_flags, bytes, dmairq; struct comedi_cmd *cmd = &s->async->cmd; + unsigned int dma_flags, bytes, dmairq; unsigned int seglen; if (devpriv->irq_blocked) return -EBUSY; - if (cmd->convert_src == TRIG_TIMER) { - if (cmd->convert_arg < 10000) - cmd->convert_arg = 10000; - - i8253_cascade_ns_to_timer(I8254_OSC_BASE_10MHZ, - &divisor1, &divisor2, - &cmd->convert_arg, cmd->flags); - - /* PCL816 crash if any divisor is set to 1 */ - if (divisor1 == 1) { - divisor1 = 2; - divisor2 /= 2; - } - if (divisor2 == 1) { - divisor2 = 2; - divisor1 /= 2; - } - } - - pcl816_start_pacer(dev, false, 0, 0); + pcl816_start_pacer(dev, false); seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len); if (seglen < 1) @@ -549,7 +534,7 @@ static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) enable_dma(devpriv->dma); } - pcl816_start_pacer(dev, true, divisor1, divisor2); + pcl816_start_pacer(dev, true); dmairq = ((devpriv->dma & 0x3) << 4) | (dev->irq & 0x7); switch (cmd->convert_src) { -- 2.7.4