shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-02 01:06:46 +09:00
Code Issues Packages Projects Releases Wiki Activity

staging: comedi: dt282x: refactor dt282x_ns_to_timer()

Browse Source 
Define the pacer clock limits and remove the magic numbers. Refactor
the code to use a common path to return the actual 'ns' timing and
the timer divisor value.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten
2016-03-23 12:24:29 -07:00
committed by Greg Kroah-Hartman
parent 47470216cc
commit 581867bd91
1 changed files with 24 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
drivers/staging/comedi/drivers/dt282x.c
View File

@@ -113,6 +113,17 @@
#define DT2821_SUPCSR_XCLK BIT(1)
#define DT2821_SUPCSR_BDINIT BIT(0)
#define DT2821_TMRCTR_REG 0x0e
#define DT2821_TMRCTR_PRESCALE(x) (((x) & 0xf) << 8)
#define DT2821_TMRCTR_DIVIDER(x) ((255 - ((x) & 0xff)) << 0)
/* Pacer Clock */
#define DT2821_OSC_BASE 250 /* 4 MHz (in nanoseconds) */
#define DT2821_PRESCALE(x) BIT(x)
#define DT2821_PRESCALE_MAX 15
#define DT2821_DIVIDER_MAX 255
#define DT2821_OSC_MAX (DT2821_OSC_BASE * \
DT2821_PRESCALE(DT2821_PRESCALE_MAX) * \
DT2821_DIVIDER_MAX)
static const struct comedi_lrange range_dt282x_ai_lo_bipolar = {
4, {
@@ -365,10 +376,10 @@ static unsigned int dt282x_ns_to_timer(unsigned int *ns, unsigned int flags)
{
unsigned int prescale, base, divider;
for (prescale = 0; prescale < 16; prescale++) {
if (prescale == 1)
for (prescale = 0; prescale <= DT2821_PRESCALE_MAX; prescale++) {
if (prescale == 1) /* 0 and 1 are both divide by 1 */
continue;
base = 250 * (1 << prescale);
base = DT2821_OSC_BASE * DT2821_PRESCALE(prescale);
switch (flags & CMDF_ROUND_MASK) {
case CMDF_ROUND_NEAREST:
default:
@@ -381,15 +392,17 @@ static unsigned int dt282x_ns_to_timer(unsigned int *ns, unsigned int flags)
divider = DIV_ROUND_UP(*ns, base);
break;
}
if (divider < 256) {
*ns = divider * base;
return (prescale << 8) | (255 - divider);
}
if (divider <= DT2821_DIVIDER_MAX)
break;
}
if (divider > DT2821_DIVIDER_MAX) {
prescale = DT2821_PRESCALE_MAX;
divider = DT2821_DIVIDER_MAX;
base = DT2821_OSC_BASE * DT2821_PRESCALE(prescale);
}
base = 250 * (1 << 15);
divider = 255;
*ns = divider * base;
return (15 << 8) | (255 - divider);
return DT2821_TMRCTR_PRESCALE(prescale) |
DT2821_TMRCTR_DIVIDER(divider);
}
static void dt282x_munge(struct comedi_device *dev,
@@ -689,8 +702,7 @@ static int dt282x_ai_cmdtest(struct comedi_device *dev,
err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 4000);
#define SLOWEST_TIMER (250*(1<<15)*255)
err |= comedi_check_trigger_arg_max(&cmd->convert_arg, SLOWEST_TIMER);
err |= comedi_check_trigger_arg_max(&cmd->convert_arg, DT2821_OSC_MAX);
err |= comedi_check_trigger_arg_min(&cmd->convert_arg, board->ai_speed);
err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
cmd->chanlist_len);