From: Thierry Reding <thierry.reding@gmail.com>
To: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: robh+dt@kernel.org, u.kleine-koenig@pengutronix.de,
alexandre.torgue@st.com, mark.rutland@arm.com,
mcoquelin.stm32@gmail.com, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
benjamin.gaignard@st.com,
linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH v2 3/3] pwm: stm32: add power management support
Date: Wed, 16 Oct 2019 09:06:35 +0200 [thread overview]
Message-ID: <20191016070635.GC1296874@ulmo> (raw)
In-Reply-To: <1570193633-6600-4-git-send-email-fabrice.gasnier@st.com>
[-- Attachment #1: Type: text/plain, Size: 3230 bytes --]
On Fri, Oct 04, 2019 at 02:53:53PM +0200, Fabrice Gasnier wrote:
> Add suspend/resume PM sleep ops. When going to low power, enforce the PWM
> channel isn't active. Let the PWM consumers disable it during their own
> suspend sequence, see [1]. So, perform a check here, and handle the
> pinctrl states. Also restore the break inputs upon resume, as registers
> content may be lost when going to low power mode.
>
> [1] https://lkml.org/lkml/2019/2/5/770
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> ---
> Changes in v2:
> Follow Uwe suggestions/remarks:
> - Add a precursor patch to ease reviewing
> - Use registers read instead of pwm_get_state
> - Add a comment to mention registers content may be lost in low power mode
> ---
> drivers/pwm/pwm-stm32.c | 38 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
Applied, thanks. I made two minor changes, though, see below.
>
> diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
> index cf8658c..546b661 100644
> --- a/drivers/pwm/pwm-stm32.c
> +++ b/drivers/pwm/pwm-stm32.c
> @@ -12,6 +12,7 @@
> #include <linux/mfd/stm32-timers.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/pinctrl/consumer.h>
> #include <linux/platform_device.h>
> #include <linux/pwm.h>
>
> @@ -655,6 +656,42 @@ static int stm32_pwm_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static int __maybe_unused stm32_pwm_suspend(struct device *dev)
> +{
> + struct stm32_pwm *priv = dev_get_drvdata(dev);
> + unsigned int ch;
I renamed this to just "i", which is more idiomatic for loop variables.
The function is small enough not to need to differentiate between loop
variables.
> + u32 ccer, mask;
> +
> + /* Look for active channels */
> + ccer = active_channels(priv);
> +
> + for (ch = 0; ch < priv->chip.npwm; ch++) {
> + mask = TIM_CCER_CC1E << (ch * 4);
> + if (ccer & mask) {
> + dev_err(dev, "The consumer didn't stop us (%s)\n",
> + priv->chip.pwms[ch].label);
Changed this to:
"PWM %u still in use by consumer %s\n", i, priv->chip.pwms[i].label
I think that might help clarify which PWM is still enabled in case the
consumers don't set a label.
Thierry
> + return -EBUSY;
> + }
> + }
> +
> + return pinctrl_pm_select_sleep_state(dev);
> +}
> +
> +static int __maybe_unused stm32_pwm_resume(struct device *dev)
> +{
> + struct stm32_pwm *priv = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = pinctrl_pm_select_default_state(dev);
> + if (ret)
> + return ret;
> +
> + /* restore breakinput registers that may have been lost in low power */
> + return stm32_pwm_apply_breakinputs(priv);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume);
> +
> static const struct of_device_id stm32_pwm_of_match[] = {
> { .compatible = "st,stm32-pwm", },
> { /* end node */ },
> @@ -667,6 +704,7 @@ static struct platform_driver stm32_pwm_driver = {
> .driver = {
> .name = "stm32-pwm",
> .of_match_table = stm32_pwm_of_match,
> + .pm = &stm32_pwm_pm_ops,
> },
> };
> module_platform_driver(stm32_pwm_driver);
> --
> 2.7.4
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2019-10-16 7:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-04 12:53 [PATCH v2 0/3] Add PM support to STM32 Timer PWM Fabrice Gasnier
2019-10-04 12:53 ` [PATCH v2 1/3] dt-bindings: pwm-stm32: document pinctrl sleep state Fabrice Gasnier
2019-10-11 15:10 ` Rob Herring
2019-10-16 6:59 ` Thierry Reding
2019-10-04 12:53 ` [PATCH v2 2/3] pwm: stm32: split breakinput apply routine to ease PM support Fabrice Gasnier
2019-10-16 7:03 ` Thierry Reding
2019-10-04 12:53 ` [PATCH v2 3/3] pwm: stm32: add power management support Fabrice Gasnier
2019-10-16 7:06 ` Thierry Reding [this message]
2019-10-16 10:08 ` Fabrice Gasnier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191016070635.GC1296874@ulmo \
--to=thierry.reding@gmail.com \
--cc=alexandre.torgue@st.com \
--cc=benjamin.gaignard@st.com \
--cc=devicetree@vger.kernel.org \
--cc=fabrice.gasnier@st.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pwm@vger.kernel.org \
--cc=linux-stm32@st-md-mailman.stormreply.com \
--cc=mark.rutland@arm.com \
--cc=mcoquelin.stm32@gmail.com \
--cc=robh+dt@kernel.org \
--cc=u.kleine-koenig@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).