From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36758 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933091AbcFLVf4 (ORCPT ); Sun, 12 Jun 2016 17:35:56 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Bjorn Andersson" , "Stephen Boyd" , "Dmitry Torokhov" , "John Stultz" Date: Sun, 12 Jun 2016 22:34:41 +0100 Message-ID: Subject: [PATCH 3.2 18/46] Input: pmic8xxx-pwrkey - fix algorithm for converting trigger delay In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.2.81-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Boyd 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. Reported-by: Bjorn Andersson Fixes: 92d57a73e410 ("input: Add support for Qualcomm PMIC8XXX power key") Signed-off-by: Stephen Boyd Tested-by: John Stultz Acked-by: Bjorn Andersson Signed-off-by: Dmitry Torokhov [bwh: Backported to 3.2: use pdata->kpd_trigger_delay_us not kpd_delay] Signed-off-by: Ben Hutchings --- --- a/drivers/input/misc/pmic8xxx-pwrkey.c +++ b/drivers/input/misc/pmic8xxx-pwrkey.c @@ -98,7 +98,9 @@ static int __devinit pmic8xxx_pwrkey_pro return -EINVAL; } - if (pdata->kpd_trigger_delay_us > 62500) { + /* Valid range of pwr key trigger delay is 1/64 sec to 2 seconds. */ + if (pdata->kpd_trigger_delay_us > USEC_PER_SEC * 2 || + pdata->kpd_trigger_delay_us < USEC_PER_SEC / 64) { dev_err(&pdev->dev, "invalid power key trigger delay\n"); return -EINVAL; } @@ -120,8 +122,8 @@ static int __devinit pmic8xxx_pwrkey_pro pwr->phys = "pmic8xxx_pwrkey/input0"; pwr->dev.parent = &pdev->dev; - delay = (pdata->kpd_trigger_delay_us << 10) / USEC_PER_SEC; - delay = 1 + ilog2(delay); + delay = (pdata->kpd_trigger_delay_us << 6) / USEC_PER_SEC; + delay = ilog2(delay); err = pm8xxx_readb(pdev->dev.parent, PON_CNTL_1, &pon_cntl); if (err < 0) {