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* [PATCH 2/3] iio: qcom-spmi-iadc: cleanup wait_for_completion return handling
@ 2015-02-02  8:37 Nicholas Mc Guire
  2015-02-04 16:59 ` Jonathan Cameron
  0 siblings, 1 reply; 3+ messages in thread
From: Nicholas Mc Guire @ 2015-02-02  8:37 UTC (permalink / raw)
  To: Jonathan Cameron
  Cc: Hartmut Knaack, Lars-Peter Clausen, Peter Meerwald,
	Ivan T. Ivanov, linux-iio, linux-kernel, Nicholas Mc Guire

This patch fixes two issues:
* return type of wait_for_completion_timeout is unsigned long not int, 
  rather than adding a dedicated variable the wait_for_completion_timeout
  is moved into the condition directly
* the timeout of wait_for_completion_timeout is in jiffies but the value
  being passed was a unsigned long not converted to jiffies and thus was
  dependent on the HZ settings which is probably not what you want.

Signed-off-by: Nicholas Mc Guire <>

Note that the timeout value changed very significantly as wait was 
initially in the range of 2 milliseconds, so this converts to 1 jiffies
for HZ < 1000 and 2 jiffies for HZ=1000 - thus the timeout value changed
by 3 orders of magnitude. This needs a review by someone that knows the
details of the hardware to judge if this change is ok - in any case the
timeout passed should go through usecs_to_jiffies or msecs_to_jiffis and
to ensure it is no longer HZ dependent.

Patch was compile tested only for imx_v6_v7_defconfig + CONFIG_IIO=m

Patch is against 3.19.0-rc6 -next-20150130

 drivers/iio/adc/qcom-spmi-iadc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/qcom-spmi-iadc.c b/drivers/iio/adc/qcom-spmi-iadc.c
index b9666f2..61fb88d 100644
--- a/drivers/iio/adc/qcom-spmi-iadc.c
+++ b/drivers/iio/adc/qcom-spmi-iadc.c
@@ -296,8 +296,8 @@ static int iadc_do_conversion(struct iadc_chip *iadc, int chan, u16 *data)
 	if (iadc->poll_eoc) {
 		ret = iadc_poll_wait_eoc(iadc, wait);
 	} else {
-		ret = wait_for_completion_timeout(&iadc->complete, wait);
-		if (!ret)
+		if (!wait_for_completion_timeout(&iadc->complete, 
+				usecs_to_jiffies(wait)))
 			ret = -ETIMEDOUT;
 			/* double check conversion status */

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2015-02-05 12:23 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2015-02-02  8:37 [PATCH 2/3] iio: qcom-spmi-iadc: cleanup wait_for_completion return handling Nicholas Mc Guire
2015-02-04 16:59 ` Jonathan Cameron
2015-02-05 12:23   ` Ivan T. Ivanov

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