Patch "iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
iio-adc-ti_am335x_adc-increase-timeout-value-waiting-for-adc-sample.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Vignesh R <[email protected]>
Date: Wed, 17 Aug 2016 17:43:01 +0530
Subject: iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample

From: Vignesh R <[email protected]>

commit 7175cce1c3f1d8c8840d2004f78f96a3904249b5 upstream.

Now that open delay and sample delay for each channel is configurable via DT, the default IDLE_TIMEOUT value is not enough as this is calculated based on hardcoded macros. This results in driver returning EBUSY sometimes. Fix this by increasing the timeout
value based on maximum value possible to open delay and sample delays for each channel.

---
 drivers/iio/adc/ti_am335x_adc.c      |    2 +-
 include/linux/mfd/ti_am335x_tscadc.h |    8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

@@ -382,7 +382,7 @@ static int tiadc_read_raw(struct iio_dev
 
 	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
 
-	timeout = jiffies + usecs_to_jiffies
+	timeout = jiffies + msecs_to_jiffies
 				(IDLE_TIMEOUT * adc_dev->channels);
 	/* Wait for Fifo threshold interrupt */
 	while (1) {

@@ -138,16 +138,16 @@
 /*
  * time in us for processing a single channel, calculated as follows:
  *
- * num cycles = open delay + (sample delay + conv time) * averaging
+ * max num cycles = open delay + (sample delay + conv time) * averaging
  *
- * num cycles: 152 + (1 + 13) * 16 = 376
+ * max num cycles: 262143 + (255 + 13) * 16 = 266431
  *
  * clock frequency: 26MHz / 8 = 3.25MHz
  * clock period: 1 / 3.25MHz = 308ns
  *
- * processing time: 376 * 308ns = 116us
+ * max processing time: 266431 * 308ns = 83ms(approx)
  */
-#define IDLE_TIMEOUT 116 /* microsec */
+#define IDLE_TIMEOUT 83 /* milliseconds */
 
 #define TSCADC_CELLS		2
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/iio-adc-ti_am335x_adc-protect-fifo1-from-concurrent-access.patch queue-4.4/iio-adc-ti_am335x_adc-increase-timeout-value-waiting-for-adc-sample.patch