From: "Guido Günther" <agx@sigxcpu.org>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Sam Ravnborg <sam@ravnborg.org>, Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
linux-kernel@vger.kernel.org,
Kishon Vijay Abraham I <kishon@ti.com>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Robert Chiras <robert.chiras@nxp.com>,
Fabio Estevam <festevam@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm
Date: Wed, 16 Dec 2020 19:25:05 +0100 [thread overview]
Message-ID: <20201216182505.GA51879@bogon.m.sigxcpu.org> (raw)
In-Reply-To: <ee22b072e0abe07559a3e6a63ccf6ece064a46cb.camel@pengutronix.de>
Hi Lucas,
On Wed, Dec 16, 2020 at 01:05:36PM +0100, Lucas Stach wrote:
> Hi Guido,
>
> this time hopefully with less broken quoting. My mailer is driving me
> mad right now...
>
> Am Mittwoch, dem 16.12.2020 um 12:27 +0100 schrieb Guido Günther:
> > This allows us to shut down the mipi power domain on the imx8. The
> > alternative would be to drop the dphy from the mipi power domain in the
> > SOCs device tree and only have the DSI host controller visible there but
> > since the PD is mostly about the PHY that would defeat it's purpose.
>
> Adding RPM support is exactly the right course of action.
Thanks for confirming!
>
> > This allows to shut off the power domain hen blanking the LCD panel:
> >
> > pm_genpd_summary before:
> >
> > domain status slaves
> > /device runtime status
> > ----------------------------------------------------------------------
> > mipi on
> > /devices/platform/soc@0/soc@0:bus@30800000/30a00300.dphy unsupported
> > /devices/platform/soc@0/soc@0:bus@30800000/30a00000.mipi_dsi suspended
> >
> > after:
> >
> > mipi off-0
> > /devices/platform/soc@0/soc@0:bus@30800000/30a00300.dphy suspended
> > /devices/platform/soc@0/soc@0:bus@30800000/30a00000.mipi_dsi suspended
> >
> > Signed-off-by: Guido Günther <agx@sigxcpu.org>
> > ---
> > .../phy/freescale/phy-fsl-imx8-mipi-dphy.c | 22 ++++++++++++++++++-
> > 1 file changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> > index a95572b397ca..34e2d801e520 100644
> > --- a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> > +++ b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> > @@ -14,6 +14,7 @@
> > #include <linux/of_platform.h>
> > #include <linux/phy/phy.h>
> > #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/regmap.h>
> >
> > /* DPHY registers */
> > @@ -93,6 +94,7 @@ struct mixel_dphy_cfg {
> > };
> >
> > struct mixel_dphy_priv {
> > + struct device *dev;
> > struct mixel_dphy_cfg cfg;
> > struct regmap *regmap;
> > struct clk *phy_ref_clk;
> > @@ -382,6 +384,7 @@ static int mixel_dphy_power_on(struct phy *phy)
> > ret = clk_prepare_enable(priv->phy_ref_clk);
> > if (ret < 0)
> > return ret;
> > + pm_runtime_get_sync(priv->dev);
> >
>
> This call can fail and will leave you with an elevated rpm refcount.
> Better use the new pm_runtime_resume_and_get to avoid this issue?
pm_runtime_resume_and_get is a nice API addition indeed.
I added the error handling but opted to stay with `pm_runtime_get_sync`
in this case since the error path already has a pm_runtime_put() hence
avoiding another goto target.
>
> Nitpick: I would add a blank line before the call.
Done.
Thanks for having a look!
-- Guido
>
> Regards,
> Lucas
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-16 18:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-16 11:27 [PATCH v2 0/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm Guido Günther
2020-12-16 11:27 ` [PATCH v2 1/1] " Guido Günther
2020-12-16 11:58 ` Lucas Stach
2020-12-16 12:05 ` Lucas Stach
2020-12-16 18:25 ` Guido Günther [this message]
2021-02-20 5:37 ` Liu Ying
2021-02-20 5:50 ` Liu Ying
2021-02-22 18:39 ` Guido Günther
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=20201216182505.GA51879@bogon.m.sigxcpu.org \
--to=agx@sigxcpu.org \
--cc=festevam@gmail.com \
--cc=kernel@pengutronix.de \
--cc=kishon@ti.com \
--cc=l.stach@pengutronix.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-imx@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=robert.chiras@nxp.com \
--cc=s.hauer@pengutronix.de \
--cc=sam@ravnborg.org \
--cc=shawnguo@kernel.org \
/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).