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pwm: qpnp: use the correct parameter to check the change of PWM period 

"pwm->period" is an external parameter that will be updated out
of the pwm-qpnp driver unexpectedly. It's improper to use this
parameter to check whether the expected period is different from
the one being used. "chip->pwm_config.pwm_period" is a pwm-qpnp
internal parameter, which always represents the current period,
so use it to fix the problem.

Change-Id: I455b828c8c9270ef0f32ab3533daa1bc2c7d183d
Signed-off-by: Xu Kai <kaixu@codeaurora.org>
This commit is contained in:
Xu Kai 2014-04-21 11:45:37 +08:00
parent 04f8a4e5ef
commit 3044bc94e9
1 changed files with 4 additions and 2 deletions
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6
drivers/pwm/pwm-qpnp.c
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@ -1,4 +1,4 @@
/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
/* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@ -1227,6 +1227,7 @@ static int qpnp_pwm_config(struct pwm_chip *pwm_chip,
int rc;
unsigned long flags;
struct qpnp_pwm_chip *chip = qpnp_pwm_from_pwm_chip(pwm_chip);
int prev_period_us = chip->pwm_config.pwm_period;
if ((unsigned)period_ns < PM_PWM_PERIOD_MIN * NSEC_PER_USEC) {
pr_err("Invalid pwm handle or parameters\n");
@ -1235,7 +1236,8 @@ static int qpnp_pwm_config(struct pwm_chip *pwm_chip,
spin_lock_irqsave(&chip->lpg_lock, flags);
if (pwm->period != period_ns) {
if (prev_period_us > INT_MAX / NSEC_PER_USEC ||
prev_period_us * NSEC_PER_USEC != period_ns) {
qpnp_lpg_calc_period(LVL_NSEC, period_ns, chip);
qpnp_lpg_save_period(chip);
pwm->period = period_ns;