From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gofer.mess.org (gofer.mess.org [88.97.38.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9102B4C65; Sat, 13 Jan 2024 16:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mess.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="G/I/b9oK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1705163200; bh=RQlY+jEYkNLZGSgB/4+Cf47fWKFdF0+OLYk1Sb7uF+w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G/I/b9oKpQhGjP/14desRRYG8sMKpLx0JWeRFYydyZP7r/cFiUD/Y11H2OamR/UNm OkEGffzV7F0OAAUeJQqTvGegggOR/usBXKq6LPgePZuFk525StbLlBi6+gc9+RY8gP iy/UNECCrwYRIBhq43eBj8CISLvN1l7AHeUO6fPP3DrD+7EuV4lIl5WSUe6dTc6bPW WVoV9gN74SHfkAVy3Cu9T/A9uvkA0PI/sMNePG1Hn8xsL2x3uOBysXFOhRpMJN5Imu SI1c2JtdZnP37Rq3iGD82NCNpvyKF0360mVtffbiRlqqGG3rPMRzWZov9rX1a8qlSk MTjIfaslZq4uQ== Received: by gofer.mess.org (Postfix, from userid 1000) id 6091C1000C6; Sat, 13 Jan 2024 16:26:40 +0000 (GMT) Date: Sat, 13 Jan 2024 16:26:40 +0000 From: Sean Young To: Ivaylo Dimitrov Cc: daniel.lezcano@linaro.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, tony@atomide.com, linux-pwm@vger.kernel.org Subject: Re: [PATCH] drivers/clocksource/timer-ti-dm: Don't call clk_get_rate() in stop function Message-ID: References: <1696312220-11550-1-git-send-email-ivo.g.dimitrov.75@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1696312220-11550-1-git-send-email-ivo.g.dimitrov.75@gmail.com> Hi Ivaylo, On Tue, Oct 03, 2023 at 08:50:20AM +0300, Ivaylo Dimitrov wrote: > clk_get_rate() might sleep, and that prevents dm-timer based PWM from being > used from atomic context. Now that this is merged, pwm-ir-tx can only use the pwm in atomic context if pwm-omap-timer.c sets the atomic field like the rpi pwm does here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pwm/pwm-bcm2835.c#n175 see pwm-ir-tx here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/media/rc/pwm-ir-tx.c#n170 It would be nice to have this tested and working properly for the n900. Thanks, Sean > > Fix that by getting fclk rate in probe() and using a notifier in case rate > changes. > > Fixes: af04aa856e93 ("ARM: OMAP: Move dmtimer driver out of plat-omap to drivers under clocksource") > Signed-off-by: Ivaylo Dimitrov > --- > drivers/clocksource/timer-ti-dm.c | 36 ++++++++++++++++++++++++++++-------- > 1 file changed, 28 insertions(+), 8 deletions(-) > > diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c > index 09ab29c..5f60f6b 100644 > --- a/drivers/clocksource/timer-ti-dm.c > +++ b/drivers/clocksource/timer-ti-dm.c > @@ -140,6 +140,8 @@ struct dmtimer { > struct platform_device *pdev; > struct list_head node; > struct notifier_block nb; > + struct notifier_block fclk_nb; > + unsigned long fclk_rate; > }; > > static u32 omap_reserved_systimers; > @@ -253,8 +255,7 @@ static inline void __omap_dm_timer_enable_posted(struct dmtimer *timer) > timer->posted = OMAP_TIMER_POSTED; > } > > -static inline void __omap_dm_timer_stop(struct dmtimer *timer, > - unsigned long rate) > +static inline void __omap_dm_timer_stop(struct dmtimer *timer) > { > u32 l; > > @@ -269,7 +270,7 @@ static inline void __omap_dm_timer_stop(struct dmtimer *timer, > * Wait for functional clock period x 3.5 to make sure that > * timer is stopped > */ > - udelay(3500000 / rate + 1); > + udelay(3500000 / timer->fclk_rate + 1); > #endif > } > > @@ -348,6 +349,21 @@ static int omap_timer_context_notifier(struct notifier_block *nb, > return NOTIFY_OK; > } > > +static int omap_timer_fclk_notifier(struct notifier_block *nb, > + unsigned long event, void *data) > +{ > + struct clk_notifier_data *clk_data = data; > + struct dmtimer *timer = container_of(nb, struct dmtimer, fclk_nb); > + > + switch (event) { > + case POST_RATE_CHANGE: > + timer->fclk_rate = clk_data->new_rate; > + return NOTIFY_OK; > + default: > + return NOTIFY_DONE; > + } > +} > + > static int omap_dm_timer_reset(struct dmtimer *timer) > { > u32 l, timeout = 100000; > @@ -754,7 +770,6 @@ static int omap_dm_timer_stop(struct omap_dm_timer *cookie) > { > struct dmtimer *timer; > struct device *dev; > - unsigned long rate = 0; > > timer = to_dmtimer(cookie); > if (unlikely(!timer)) > @@ -762,10 +777,7 @@ static int omap_dm_timer_stop(struct omap_dm_timer *cookie) > > dev = &timer->pdev->dev; > > - if (!timer->omap1) > - rate = clk_get_rate(timer->fclk); > - > - __omap_dm_timer_stop(timer, rate); > + __omap_dm_timer_stop(timer); > > pm_runtime_put_sync(dev); > > @@ -1124,6 +1136,14 @@ static int omap_dm_timer_probe(struct platform_device *pdev) > timer->fclk = devm_clk_get(dev, "fck"); > if (IS_ERR(timer->fclk)) > return PTR_ERR(timer->fclk); > + > + timer->fclk_nb.notifier_call = omap_timer_fclk_notifier; > + ret = devm_clk_notifier_register(dev, timer->fclk, > + &timer->fclk_nb); > + if (ret) > + return ret; > + > + timer->fclk_rate = clk_get_rate(timer->fclk); > } else { > timer->fclk = ERR_PTR(-ENODEV); > } > -- > 1.9.1