phy: fsl-imx8-mipi-dphy: Hook into runtime pm

PATCH Superseded Guido Günther 2 participants 4 messages Feb 22, 2021 – Feb 23, 2021

Subsystems (2)

Arm i.MX and Layerscape Generic PHY framework

lore

Share & tools

lore

Guido Günther

author

2021-02-22 18:39 UTC #0 lore raw

v4 cover phy: fsl-imx8-mipi-dphy: Hook into runtime pm

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/[email protected]/
Check for pm_runtime_get_sync failure

Changes from v3:
- As per review comment by Liu Ying
https://lore.kernel.org/linux-arm-kernel/[email protected]/
https://lore.kernel.org/linux-arm-kernel/[email protected]/
- 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(+)

Signature · 7 lines

2.30.0


_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Guido Günther

author

2021-02-22 18:39 UTC #1 lore raw

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

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 <[email protected]>

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

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +10 -0

index a95572b397ca..5de175695834 100644
@@ -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,

Signature · 7 lines

2.30.0


_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Liu Ying

2021-02-23 02:39 UTC #2 lore raw

Hi Guido,

Quoted 6 lines · 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:

s/hen/when/

Quoted 34 lines

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 <[email protected]>
---
 drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0
index a95572b397ca..5de175695834 100644
@@ -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 */

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 474

Quoted 5 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +2 -0

@@ -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

Quoted 19 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +7 -0

 	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,

Liu Ying

2021-02-23 02:57 UTC #3 lore raw

Quoted 54 lines · Liu Ying

Hi Guido,
Quoted 6 lines · 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:
s/hen/when/
Quoted 33 lines
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 <[email protected]>
---
 drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0
index a95572b397ca..5de175695834 100644
@@ -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 */
drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 474
Quoted 5 lines
drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +2 -0
@@ -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.

Quoted 7 lines

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

Quoted 25 lines

get/put runtime PM in mixel_dphy_configure().

Regards,
Liu Ying

Quoted 19 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +7 -0

 	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,