From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Richardson Subject: [PATCH v9 2/2] pwm: core: Set enable state properly on failed call to enable Date: Mon, 15 Jun 2015 14:21:02 -0700 Message-ID: <1434403262-24198-3-git-send-email-jonathar@broadcom.com> References: <1434403262-24198-1-git-send-email-jonathar@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-gw3-out.broadcom.com ([216.31.210.64]:41577 "EHLO mail-gw3-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087AbbFOVRf (ORCPT ); Mon, 15 Jun 2015 17:17:35 -0400 In-Reply-To: <1434403262-24198-1-git-send-email-jonathar@broadcom.com> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Tim Kryger , Dmitry Torokhov , Anatol Pomazau , Arun Ramamurthy , Thierry Reding Cc: Scott Branden , Jonathan Richardson , bcm-kernel-feedback-list , linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org The pwm_enable function didn't clear the enabled bit if a call to a clients enable function returned an error. The result was that the state of the pwm core was wrong. Clearing the bit when enable returns an error ensures the state is properly set. Tested-by: Jonathan Richardson Reviewed-by: Dmitry Torokhov Signed-off-by: Jonathan Richardson --- drivers/pwm/core.c | 19 ++++++++++++++++--- include/linux/pwm.h | 2 ++ 2 files changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 76b0386..c255267 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -263,6 +263,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, pwm->pwm = chip->base + i; pwm->hwpwm = i; pwm->polarity = polarity; + mutex_init(&pwm->lock); radix_tree_insert(&pwm_tree, pwm->pwm, pwm); } @@ -474,10 +475,22 @@ EXPORT_SYMBOL_GPL(pwm_set_polarity); */ int pwm_enable(struct pwm_device *pwm) { - if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags)) - return pwm->chip->ops->enable(pwm->chip, pwm); + int err = 0; - return pwm ? 0 : -EINVAL; + if (!pwm) + return -EINVAL; + + mutex_lock(&pwm->lock); + + if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) { + err = pwm->chip->ops->enable(pwm->chip, pwm); + if (err) + clear_bit(PWMF_ENABLED, &pwm->flags); + } + + mutex_unlock(&pwm->lock); + + return err; } EXPORT_SYMBOL_GPL(pwm_enable); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 9daf0ef..50f28e6 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -3,6 +3,7 @@ #include #include +#include struct pwm_device; struct seq_file; @@ -86,6 +87,7 @@ struct pwm_device { unsigned int pwm; struct pwm_chip *chip; void *chip_data; + struct mutex lock; unsigned int period; /* in nanoseconds */ unsigned int duty_cycle; /* in nanoseconds */ -- 1.7.9.5