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Subject[PATCH v6] Staging: comedi: convert while loop to timeout in ni_mio_common.c
Date
This patch for ni_mio_common.c changes out a while loop for a timeout,
which is preferred.

Signed-off-by: Chase Southwood <chase.southwood@yahoo.com>
---

2: Changed from simple clean-up to swapping a timeout in for a while loop.

3: Removed extra counter variable, and added error checking.

4: No longer using counter variable, using jiffies instead.

5: udelay for 10u, instead of 1u.

6: Scrap udelay entirely, in favor of cpu_relax. Include asm/processor.h
in order to use cpu_relax.

drivers/staging/comedi/drivers/ni_mio_common.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index 457b884..fe2f434 100644
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -55,6 +55,7 @@
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/delay.h>
+#include <asm/processor.h>
#include "8255.h"
#include "mite.h"
#include "comedi_fc.h"
@@ -687,12 +688,21 @@ static void ni_clear_ai_fifo(struct comedi_device *dev)
{
const struct ni_board_struct *board = comedi_board(dev);
struct ni_private *devpriv = dev->private;
+ unsigned long timeout;

if (board->reg_type == ni_reg_6143) {
/* Flush the 6143 data FIFO */
ni_writel(0x10, AIFIFO_Control_6143); /* Flush fifo */
ni_writel(0x00, AIFIFO_Control_6143); /* Flush fifo */
- while (ni_readl(AIFIFO_Status_6143) & 0x10) ; /* Wait for complete */
+ /* Wait for complete */
+ timeout = jiffies + msec_to_jiffies(500);
+ while (ni_readl(AIFIFO_Status_6143) & 0x10) {
+ if (time_after(jiffies, timeout)) {
+ comedi_error(dev, "FIFO flush timeout.");
+ break;
+ }
+ cpu_relax();
+ }
} else {
devpriv->stc_writew(dev, 1, ADC_FIFO_Clear);
if (board->reg_type == ni_reg_625x) {
--
1.8.4.2


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