[PATCH v4 0/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

[PATCH v4 0/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

[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.

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

Changes from v1:
 - Tweak commit message slightly

Changes from v2:
  - As per review comment by Lucas Stach
    https://lore.kernel.org/linux-arm-kernel/ee22b072e0abe07559a3e6a63ccf6ece064a46cb.camel@pengutronix.de/
    Check for pm_runtime_get_sync failure

Changes from v3:
  - As per review comment by Liu Ying
    https://lore.kernel.org/linux-arm-kernel/424af315b677934fe6a91cee5a0a7aee058245a9.camel@nxp.com/
    https://lore.kernel.org/linux-arm-kernel/a98f7531b9d0293d3c89174446f742d4199cb27c.camel@nxp.com/
    - Use phy layers runtime pm
    - simplify mixel_dphy_remove



Guido Günther (1):
  phy: fsl-imx8-mipi-dphy: Hook into runtime pm

 drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

-- 
2.30.0


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[PATCH v4 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

[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.

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>
---
 drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
index a95572b397ca..5de175695834 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 */
@@ -469,6 +470,8 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 
 	dev_set_drvdata(dev, priv);
 
+	pm_runtime_enable(dev);
+
 	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);
 	if (IS_ERR(phy)) {
 		dev_err(dev, "Failed to create phy %ld\n", PTR_ERR(phy));
@@ -481,8 +484,15 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	return PTR_ERR_OR_ZERO(phy_provider);
 }
 
+static int mixel_dphy_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+	return 0;
+}
+
 static struct platform_driver mixel_dphy_driver = {
 	.probe	= mixel_dphy_probe,
+	.remove = mixel_dphy_remove,
 	.driver = {
 		.name = "mixel-mipi-dphy",
 		.of_match_table	= mixel_dphy_of_match,
-- 
2.30.0


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Re: [PATCH v4 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

[Liu Ying]

Hi Guido,

On Mon, 2021-02-22 at 19:38 +0100, Guido Günther wrote:
> 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.
> 
> This allows to shut off the power domain hen blanking the LCD panel:

s/hen/when/

> 
> 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>
> ---
>  drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> index a95572b397ca..5de175695834 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 */
> @@ -469,6 +470,8 @@ static int mixel_dphy_probe(struct platform_device *pdev)
>  
>  	dev_set_drvdata(dev, priv);
>  
> +	pm_runtime_enable(dev);
> +

The runtime PM should be disabled if devm_phy_create()
or devm_of_phy_provider_register() fail.

Also, I'm just realizing that mixel_dphy_configure() accesses some PHY
registers, which likely needs the power domain on. However, the
phy-core doesn't manage the runtime PM for phy_configure(). It looks
that the NWL DSI bridge driver, which uses the PHY, enables the same
power domain prior to the PHY configuration. That's probably why
mixel_dphy_configure() gets power for accessing registers(if really
needed). So, perhaps, either make phy_configure() manage runtime PM or 
get/put runtime PM in mixel_dphy_configure().

Regards,
Liu Ying

>  	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);
>  	if (IS_ERR(phy)) {
>  		dev_err(dev, "Failed to create phy %ld\n", PTR_ERR(phy));
> @@ -481,8 +484,15 @@ static int mixel_dphy_probe(struct platform_device *pdev)
>  	return PTR_ERR_OR_ZERO(phy_provider);
>  }
>  
> +static int mixel_dphy_remove(struct platform_device *pdev)
> +{
> +	pm_runtime_disable(&pdev->dev);
> +	return 0;
> +}
> +
>  static struct platform_driver mixel_dphy_driver = {
>  	.probe	= mixel_dphy_probe,
> +	.remove = mixel_dphy_remove,
>  	.driver = {
>  		.name = "mixel-mipi-dphy",
>  		.of_match_table	= mixel_dphy_of_match,


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Re: [PATCH v4 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

[Liu Ying]

On Tue, 2021-02-23 at 10:36 +0800, Liu Ying wrote:
> Hi Guido,
> 
> On Mon, 2021-02-22 at 19:38 +0100, Guido Günther wrote:
> > 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.
> > 
> > This allows to shut off the power domain hen blanking the LCD panel:
> 
> s/hen/when/
> 
> > 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>
> > ---
> >  drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> > index a95572b397ca..5de175695834 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 */
> > @@ -469,6 +470,8 @@ static int mixel_dphy_probe(struct platform_device *pdev)
> >  
> >  	dev_set_drvdata(dev, priv);
> >  
> > +	pm_runtime_enable(dev);
> > +
> 
> The runtime PM should be disabled if devm_phy_create()
> or devm_of_phy_provider_register() fail.
> 
> Also, I'm just realizing that mixel_dphy_configure() accesses some PHY
> registers, which likely needs the power domain on. However, the
> phy-core doesn't manage the runtime PM for phy_configure(). It looks
> that the NWL DSI bridge driver, which uses the PHY, enables the same
> power domain prior to the PHY configuration. That's probably why
> mixel_dphy_configure() gets power for accessing registers(if really
> needed). So, perhaps, either make phy_configure() manage runtime PM or

Just to be clear, if phy_configure() is touched, be very carefully on
relevant in-tree PHYs.

Liu Ying

>  
> get/put runtime PM in mixel_dphy_configure().
> 
> Regards,
> Liu Ying
> 
> >  	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);
> >  	if (IS_ERR(phy)) {
> >  		dev_err(dev, "Failed to create phy %ld\n", PTR_ERR(phy));
> > @@ -481,8 +484,15 @@ static int mixel_dphy_probe(struct platform_device *pdev)
> >  	return PTR_ERR_OR_ZERO(phy_provider);
> >  }
> >  
> > +static int mixel_dphy_remove(struct platform_device *pdev)
> > +{
> > +	pm_runtime_disable(&pdev->dev);
> > +	return 0;
> > +}
> > +
> >  static struct platform_driver mixel_dphy_driver = {
> >  	.probe	= mixel_dphy_probe,
> > +	.remove = mixel_dphy_remove,
> >  	.driver = {
> >  		.name = "mixel-mipi-dphy",
> >  		.of_match_table	= mixel_dphy_of_match,


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