Calculate clock period taking into account prescaling.

diff --git a/comedi/drivers/ni_tio.c b/comedi/drivers/ni_tio.c
index 94cf0825e78d517769b0e12e386dafe456f6ec44..67128c4409422ef3dba1102508f353ef3d4d6d3d 100644 (file)
--- a/comedi/drivers/ni_tio.c
+++ b/comedi/drivers/ni_tio.c
@@ -46,6 +46,9 @@ DAQ 6601/6602 User Manual (NI 322137B-01)
 
 #include "ni_tio.h"
 
+static uint64_t ni_tio_clock_period_ps(const struct ni_gpct *counter, unsigned generic_clock_source);
+static unsigned ni_tio_generic_clock_src_select(struct ni_gpct *counter);
+
 MODULE_AUTHOR("Comedi <comedi@comedi.org>");
 MODULE_DESCRIPTION("Comedi support for NI general-purpose counters");
 MODULE_LICENSE("GPL");
@@ -758,6 +761,7 @@ static void ni_tio_set_sync_mode(struct ni_gpct *counter, int force_alt_sync)
 {
        const unsigned counting_mode_reg = NITIO_Gi_Counting_Mode_Reg(counter->counter_index);
        static const uint64_t min_normal_sync_period_ps = 25000;
+       const uint64_t clock_period_ps = ni_tio_clock_period_ps(counter, ni_tio_generic_clock_src_select(counter));
 
        if(ni_tio_counting_mode_registers_present(counter) == 0) return;
 
@@ -772,12 +776,11 @@ static void ni_tio_set_sync_mode(struct ni_gpct *counter, int force_alt_sync)
        default:
                break;
        }
-       /* It's not clear what we should do if clock_period_ns is set to zero, so we are not
+       /* It's not clear what we should do if clock_period is unknown, so we are not
        using the alt sync bit in that case, but allow the caller to decide by using the
        force_alt_sync parameter. */
-       /* FIXME: take into account possibility of the divide-by-8 prescale*/
        if(force_alt_sync ||
-               (counter->clock_period_ps && counter->clock_period_ps < min_normal_sync_period_ps))
+               (clock_period_ps && clock_period_ps < min_normal_sync_period_ps))
        {
                counter->regs[counting_mode_reg] |= Gi_Alternate_Sync_Bit(counter->variant);
        }else
@@ -1023,30 +1026,6 @@ static unsigned ni_m_series_source_select_bits(lsampl_t clock_source)
        return Gi_Source_Select_Bits(ni_m_series_clock);
 };
 
-static void ni_tio_update_clock_period(struct ni_gpct *counter, lsampl_t clock_source, lsampl_t period_ns)
-{
-       static const uint64_t pico_per_nano = 1000;
-
-       switch(clock_source & NI_GPCT_CLOCK_SRC_SELECT_MASK)
-       {
-       case NI_GPCT_TIMEBASE_1_CLOCK_SRC_BITS:
-               counter->clock_period_ps = 50000;
-               break;
-       case NI_GPCT_TIMEBASE_2_CLOCK_SRC_BITS:
-               counter->clock_period_ps = 10000000;
-               break;
-       case NI_GPCT_TIMEBASE_3_CLOCK_SRC_BITS:
-               counter->clock_period_ps = 12500;
-               break;
-       case NI_GPCT_PXI10_CLOCK_SRC_BITS:
-               counter->clock_period_ps = 100000;
-               break;
-       default:
-               counter->clock_period_ps = period_ns * pico_per_nano;
-               break;
-       }
-}
-
 static void ni_tio_set_source_subselect(struct ni_gpct *counter, lsampl_t clock_source)
 {
        const unsigned second_gate_reg = NITIO_Gi_Second_Gate_Reg(counter->counter_index);
@@ -1075,8 +1054,8 @@ static void ni_tio_set_source_subselect(struct ni_gpct *counter, lsampl_t clock_
 static int ni_tio_set_clock_src(struct ni_gpct *counter, lsampl_t clock_source, lsampl_t period_ns)
 {
        const unsigned input_select_reg = NITIO_Gi_Input_Select_Reg(counter->counter_index);
+       static const uint64_t pico_per_nano = 1000;
 
-/*FIXME: is clock period specified before or after prescaling?  I'm going to say after. */
 /*FIXME: validate clock source */
        counter->regs[input_select_reg] &= ~Gi_Source_Select_Mask;
        switch(counter->variant)
@@ -1122,7 +1101,7 @@ static int ni_tio_set_clock_src(struct ni_gpct *counter, lsampl_t clock_source,
                }
                counter->write_register(counter, counter->regs[counting_mode_reg], counting_mode_reg);
        }
-       ni_tio_update_clock_period(counter, clock_source, period_ns);
+       counter->clock_period_ps = pico_per_nano * period_ns;
        ni_tio_set_sync_mode(counter, 0);
        return 0;
 }
@@ -1257,24 +1236,71 @@ static unsigned ni_660x_clock_src_select(struct ni_gpct *counter)
        return clock_source;
 }
 
-static void ni_tio_get_clock_src(struct ni_gpct *counter, lsampl_t *clock_source, lsampl_t *period_ns)
+static unsigned ni_tio_generic_clock_src_select(struct ni_gpct *counter)
 {
-       static const unsigned pico_per_nano = 1000;
-       uint64_t temp64;
        switch(counter->variant)
        {
        case ni_gpct_variant_e_series:
        case ni_gpct_variant_m_series:
-               *clock_source = ni_m_series_clock_src_select(counter);
+               return ni_m_series_clock_src_select(counter);
                break;
        case ni_gpct_variant_660x:
-               *clock_source = ni_660x_clock_src_select(counter);
+               return ni_660x_clock_src_select(counter);
                break;
        default:
                BUG();
                break;
        }
-       temp64 = counter->clock_period_ps;
+       return 0;
+}
+
+static uint64_t ni_tio_clock_period_ps(const struct ni_gpct *counter, unsigned generic_clock_source)
+{
+       uint64_t clock_period_ps;
+
+       switch(generic_clock_source & NI_GPCT_CLOCK_SRC_SELECT_MASK)
+       {
+       case NI_GPCT_TIMEBASE_1_CLOCK_SRC_BITS:
+               clock_period_ps = 50000;
+               break;
+       case NI_GPCT_TIMEBASE_2_CLOCK_SRC_BITS:
+               clock_period_ps = 10000000;
+               break;
+       case NI_GPCT_TIMEBASE_3_CLOCK_SRC_BITS:
+               clock_period_ps = 12500;
+               break;
+       case NI_GPCT_PXI10_CLOCK_SRC_BITS:
+               clock_period_ps = 100000;
+               break;
+       default:
+               /* clock period is specified by user with prescaling already taken into account. */
+               return counter->clock_period_ps;
+               break;
+       }
+
+       switch(generic_clock_source & NI_GPCT_PRESCALE_MODE_CLOCK_SRC_MASK)
+       {
+       case NI_GPCT_NO_PRESCALE_CLOCK_SRC_BITS:
+               break;
+       case NI_GPCT_PRESCALE_X2_CLOCK_SRC_BITS:
+               clock_period_ps *= 2;
+               break;
+       case NI_GPCT_PRESCALE_X8_CLOCK_SRC_BITS:
+               clock_period_ps *= 8;
+               break;
+       default:
+               BUG();
+               break;
+       }
+       return clock_period_ps;
+}
+
+static void ni_tio_get_clock_src(struct ni_gpct *counter, lsampl_t *clock_source, lsampl_t *period_ns)
+{
+       static const unsigned pico_per_nano = 1000;
+       uint64_t temp64;
+       *clock_source = ni_tio_generic_clock_src_select(counter);
+       temp64 = ni_tio_clock_period_ps(counter, *clock_source);
        do_div(temp64, pico_per_nano);
        *period_ns = temp64;
 }

diff --git a/comedi/drivers/ni_tio.h b/comedi/drivers/ni_tio.h
index 74bfa0ddaacaf920d14d4245c4386a46bc4ec205..b2a8609e762658d5a49ccfbdae66e074cb4e6196 100644 (file)
--- a/comedi/drivers/ni_tio.h
+++ b/comedi/drivers/ni_tio.h
@@ -91,8 +91,8 @@ struct ni_gpct
        comedi_device *dev;
        unsigned counter_index;
        unsigned chip_index;
-       void (*write_register)(struct ni_gpct *this, unsigned bits, enum ni_gpct_register);
-       unsigned (*read_register)(struct ni_gpct *this, enum ni_gpct_register);
+       void (*write_register)(struct ni_gpct *this, unsigned bits, enum ni_gpct_register reg);
+       unsigned (*read_register)(struct ni_gpct *this, enum ni_gpct_register reg);
        enum ni_gpct_variant variant;
        uint64_t clock_period_ps; /* clock period in picoseconds */
        unsigned regs[MAX_NUM_NITIO_REGS];