From: Fabrice Gasnier <fabrice.gasnier@st.com>
To: <thierry.reding@gmail.com>, <robh+dt@kernel.org>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
alexandre.torgue@st.com, tduszyns@gmail.com,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
mcoquelin.stm32@gmail.com, u.kleine-koenig@pengutronix.de,
fabrice.gasnier@st.com, linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 3/3] pwm: core: add consumer device link
Date: Mon, 11 Feb 2019 17:12:02 +0100 [thread overview]
Message-ID: <1549901522-15071-4-git-send-email-fabrice.gasnier@st.com> (raw)
In-Reply-To: <1549901522-15071-1-git-send-email-fabrice.gasnier@st.com>
Add a device link between the PWM consumer and the PWM provider. This
enforces the PWM user to get suspended before the PWM provider. It
allows proper synchronization of suspend/resume sequences: the PWM user
is responsible for properly stopping PWM, before the provider gets
suspended: see [1]. Add the device link in:
- pwm_get()
- devm_pwm_get()
- devm_of_pwm_get()
as it requires a reference to the device for the PWM consumer.
[1] https://lkml.org/lkml/2019/2/5/770
Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/pwm/core.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 1581f6a..2835e27 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -770,8 +770,13 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
int err;
/* look up via DT first */
- if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
- return of_pwm_get(dev->of_node, con_id);
+ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
+ pwm = of_pwm_get(dev->of_node, con_id);
+ if (!IS_ERR(pwm))
+ device_link_add(dev, pwm->chip->dev,
+ DL_FLAG_AUTOREMOVE_CONSUMER);
+ return pwm;
+ }
/*
* We look up the provider in the static table typically provided by
@@ -851,6 +856,8 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
pwm->args.period = chosen->period;
pwm->args.polarity = chosen->polarity;
+ device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
+
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);
@@ -943,6 +950,8 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
+ device_link_add(dev, pwm->chip->dev,
+ DL_FLAG_AUTOREMOVE_CONSUMER);
} else {
devres_free(ptr);
}
--
1.9.1
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next prev parent reply other threads:[~2019-02-11 16:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 16:11 [PATCH v2 0/3] Add PM support to STM32 LP Timer drivers Fabrice Gasnier
2019-02-11 16:12 ` [PATCH v2 1/3] dt-bindings: pwm-stm32-lp: document pinctrl sleep state Fabrice Gasnier
2019-02-11 16:12 ` [PATCH v2 2/3] pwm: stm32-lp: Add power management support Fabrice Gasnier
2019-02-11 16:12 ` Fabrice Gasnier [this message]
2019-02-11 19:06 ` [PATCH v2 3/3] pwm: core: add consumer device link Uwe Kleine-König
2019-02-12 8:31 ` Fabrice Gasnier
2019-02-12 9:03 ` Uwe Kleine-König
2019-02-13 10:51 ` Fabrice Gasnier
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