Patch "Input: pmic8xxx-pwrkey - fix algorithm for converting trigger delay" 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

Input: pmic8xxx-pwrkey - fix algorithm for converting trigger delay

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:
input-pmic8xxx-pwrkey-fix-algorithm-for-converting-trigger-delay.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: Stephen Boyd <[email protected]>
Date: Sun, 17 Apr 2016 05:21:42 -0700
Subject: Input: pmic8xxx-pwrkey - fix algorithm for converting trigger delay

From: Stephen Boyd <[email protected]>

commit eda5ecc0a6b865561997e177c393f0b0136fe3b7 upstream.

The trigger delay algorithm that converts from microseconds to the register value looks incorrect. According to most of the PMIC documentation, the equation is

	delay (Seconds) = (1 / 1024) * 2 ^ (x + 4)

except for one case where the documentation looks to have a formatting issue and the equation looks like

	delay (Seconds) = (1 / 1024) * 2 x + 4

Most likely this driver was written with the improper documentation to begin with. According to the downstream sources the valid delays are from 2 seconds to 1/64 second, and the latter equation just doesn't make sense for that. Let's fix the algorithm and the range check to match the documentation and the downstream sources.

---
 drivers/input/misc/pmic8xxx-pwrkey.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -353,7 +353,8 @@ static int pmic8xxx_pwrkey_probe(struct
 	if (of_property_read_u32(pdev->dev.of_node, "debounce", &kpd_delay))
 		kpd_delay = 15625;
 
-	if (kpd_delay > 62500 || kpd_delay == 0) {
+	/* Valid range of pwr key trigger delay is 1/64 sec to 2 seconds. */
+	if (kpd_delay > USEC_PER_SEC * 2 || kpd_delay < USEC_PER_SEC / 64) {
 		dev_err(&pdev->dev, "invalid power key trigger delay\n");
 		return -EINVAL;
 	}

@@ -385,8 +386,8 @@ static int pmic8xxx_pwrkey_probe(struct
 	pwr->name = "pmic8xxx_pwrkey";
 	pwr->phys = "pmic8xxx_pwrkey/input0";
 
-	delay = (kpd_delay << 10) / USEC_PER_SEC;
-	delay = 1 + ilog2(delay);
+	delay = (kpd_delay << 6) / USEC_PER_SEC;
+	delay = ilog2(delay);
 
 	err = regmap_read(regmap, PON_CNTL_1, &pon_cntl);
 	if (err < 0) {

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

queue-4.4/input-pmic8xxx-pwrkey-fix-algorithm-for-converting-trigger-delay.patch