From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Duszynski Subject: Re: [PATCH 2/4] pwm: stm32-lp: Add power management support Date: Tue, 5 Feb 2019 19:30:09 +0100 Message-ID: <20190205183005.GA13960@arch> References: <1549370429-19116-1-git-send-email-fabrice.gasnier@st.com> <1549370429-19116-3-git-send-email-fabrice.gasnier@st.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1549370429-19116-3-git-send-email-fabrice.gasnier@st.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Fabrice Gasnier Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, alexandre.torgue@st.com, linux-pwm@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, vilhelm.gray@gmail.com, robh+dt@kernel.org, thierry.reding@gmail.com, linux-arm-kernel@lists.infradead.org, mcoquelin.stm32@gmail.com, linux-stm32@st-md-mailman.stormreply.com, jic23@kernel.org List-Id: devicetree@vger.kernel.org On Tue, Feb 05, 2019 at 01:40:27PM +0100, Fabrice Gasnier wrote: > Add suspend/resume PM sleep ops. When going to low power, disable > active PWM channel. Active PWM channel is resumed, by calling > pwm_apply_state(). This is inspired by Thierry's comment in [1]. > Don't touch inactive channels, as it may be used by other LPTimer MFD > child driver. > [1]https://lkml.org/lkml/2017/12/5/175 > > Signed-off-by: Fabrice Gasnier > --- > drivers/pwm/pwm-stm32-lp.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c > index 0059b24c..0c40d48 100644 > --- a/drivers/pwm/pwm-stm32-lp.c > +++ b/drivers/pwm/pwm-stm32-lp.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -20,6 +21,8 @@ struct stm32_pwm_lp { > struct pwm_chip chip; > struct clk *clk; > struct regmap *regmap; > + struct pwm_state suspend; > + bool suspended; > }; > > static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip) > @@ -223,6 +226,40 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev) > return pwmchip_remove(&priv->chip); > } > > +#ifdef CONFIG_PM_SLEEP You might consider dropping ifdefs and marking pm functions with __maybe_unused instead. In case CONFIG_PM_SLEEP=n then these two guys will be removed and pm ops structure will be empty. > +static int stm32_pwm_lp_suspend(struct device *dev) > +{ > + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); > + I guess you first need to get platform_device from dev and eventually stm32_pwm_lp. Wondering how this works now. > + pwm_get_state(&priv->chip.pwms[0], &priv->suspend); > + priv->suspended = priv->suspend.enabled; > + > + /* safe to call pwm_disable() for already disabled pwm */ > + pwm_disable(&priv->chip.pwms[0]); > + > + return pinctrl_pm_select_sleep_state(dev); > +} > + > +static int stm32_pwm_lp_resume(struct device *dev) > +{ > + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); > + int ret; > + > + ret = pinctrl_pm_select_default_state(dev); > + if (ret) > + return ret; > + > + /* Only restore suspended pwm, not to disrupt other MFD child */ > + if (!priv->suspended) > + return 0; Would it make sense to use suspend.enabled directly? > + > + return pwm_apply_state(&priv->chip.pwms[0], &priv->suspend); > +} > +#endif > + > +static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend, > + stm32_pwm_lp_resume); > + > static const struct of_device_id stm32_pwm_lp_of_match[] = { > { .compatible = "st,stm32-pwm-lp", }, > {}, > @@ -235,6 +272,7 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev) > .driver = { > .name = "stm32-pwm-lp", > .of_match_table = of_match_ptr(stm32_pwm_lp_of_match), > + .pm = &stm32_pwm_lp_pm_ops, > }, > }; > module_platform_driver(stm32_pwm_lp_driver); > -- > 1.9.1 >