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

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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.

Reported-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Fixes: 92d57a73e410 ("input: Add support for Qualcomm PMIC8XXX power key")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Stephen Boyd 2016-04-17 05:21:42 -07:00 committed by Dmitry Torokhov
parent ca3704c23a
commit eda5ecc0a6
1 changed files with 4 additions and 3 deletions
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7
drivers/input/misc/pmic8xxx-pwrkey.c
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@ -353,7 +353,8 @@ static int pmic8xxx_pwrkey_probe(struct platform_device *pdev)
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 platform_device *pdev)
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) {