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

Signed-off-by Guido Günther <[email protected]>

---
 .../phy/freescale/phy-fsl-imx8-mipi-dphy.c | 22 ++++++++++++++++++-

 1 file changed, 21 insertions(+), 1 deletion(-)

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

index a95572b397ca..34e2d801e520 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 +0 -0

@@ -93,6 +94,7 @@ struct mixel_dphy_cfg {
  };

 struct mixel_dphy_priv {

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

+	struct device *dev;

  struct mixel_dphy_cfg cfg;
  struct regmap *regmap;
  struct clk *phy_ref_clk;

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

@@ -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);

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:

Quoted 4 lines

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.

Quoted 44 lines

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]>

---
 .../phy/freescale/phy-fsl-imx8-mipi-dphy.c | 22 ++++++++++++++++++-

 1 file changed, 21 insertions(+), 1 deletion(-)

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

index a95572b397ca..34e2d801e520 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 +0 -0

@@ -93,6 +94,7 @@ struct mixel_dphy_cfg {
  };

 struct mixel_dphy_priv {

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

+	struct device *dev;

  struct mixel_dphy_cfg cfg;
  struct regmap *regmap;
  struct clk *phy_ref_clk;

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

@@ -382,6 +384,7 @@ static int mixel_dphy_power_on(struct phy *phy)

Quoted 5 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -0

  	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?

Nitpick: I would add a blank line before the call.

Regards,
Lucas

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 <[email protected]>

---
 .../phy/freescale/phy-fsl-imx8-mipi-dphy.c    | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +6 -0

index a95572b397ca..34e2d801e520 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 */

@@ -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);
 
 	phy_write(phy, PWR_ON, DPHY_PD_PLL);
 	ret = regmap_read_poll_timeout(priv->regmap, DPHY_LOCK, locked,

@@ -395,6 +398,7 @@ static int mixel_dphy_power_on(struct phy *phy)
 
 	return 0;
 clock_disable:
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 	return ret;
 }

@@ -406,6 +410,7 @@ static int mixel_dphy_power_off(struct phy *phy)
 	phy_write(phy, PWR_OFF, DPHY_PD_PLL);
 	phy_write(phy, PWR_OFF, DPHY_PD_DPHY);
 
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 
 	return 0;

@@ -467,6 +472,7 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	dev_dbg(dev, "phy_ref clock rate: %lu\n",
 		clk_get_rate(priv->phy_ref_clk));
 
+	priv->dev = dev;
 	dev_set_drvdata(dev, priv);
 
 	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +12 -0

+
+	return 0;
+}
+
+static int mixel_dphy_remove(struct platform_device *pdev)
+{
+	struct mixel_dphy_priv *priv = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(priv->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,

Hi Guido,

Quoted 80 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:

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]>

---
 .../phy/freescale/phy-fsl-imx8-mipi-dphy.c    | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +6 -0

index a95572b397ca..34e2d801e520 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 */

@@ -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);
 
 	phy_write(phy, PWR_ON, DPHY_PD_PLL);
 	ret = regmap_read_poll_timeout(priv->regmap, DPHY_LOCK, locked,

@@ -395,6 +398,7 @@ static int mixel_dphy_power_on(struct phy *phy)
 
 	return 0;
 clock_disable:
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 	return ret;
 }

@@ -406,6 +410,7 @@ static int mixel_dphy_power_off(struct phy *phy)
 	phy_write(phy, PWR_OFF, DPHY_PD_PLL);
 	phy_write(phy, PWR_OFF, DPHY_PD_DPHY);
 
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 
 	return 0;

@@ -467,6 +472,7 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	dev_dbg(dev, "phy_ref clock rate: %lu\n",
 		clk_get_rate(priv->phy_ref_clk));
 
+	priv->dev = dev;
 	dev_set_drvdata(dev, priv);
 
 	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 489

Quoted 8 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +3 -1

@@ -477,12 +483,26 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	phy_set_drvdata(phy, priv);
 
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(phy_provider))
+		return PTR_ERR(phy_provider);
 
-	return PTR_ERR_OR_ZERO(phy_provider);
+	pm_runtime_enable(dev);

If this enablement is done prior to devm_phy_create(), then the phy-core will manage runtime PM for this device. This way, this driver doesn't have to manage it by itself.

Regards,
Liu Ying

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 498

Quoted 9 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +9 -0

+
+	return 0;
+}
+
+static int mixel_dphy_remove(struct platform_device *pdev)
+{
+	struct mixel_dphy_priv *priv = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(priv->dev);

Quoted 10 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +3 -0

+
+	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,

Hi Guido,

Quoted 86 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:

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]>

---
 .../phy/freescale/phy-fsl-imx8-mipi-dphy.c    | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +8 -0

index a95572b397ca..34e2d801e520 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 */

@@ -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);
 
 	phy_write(phy, PWR_ON, DPHY_PD_PLL);
 	ret = regmap_read_poll_timeout(priv->regmap, DPHY_LOCK, locked,

@@ -395,6 +398,7 @@ static int mixel_dphy_power_on(struct phy *phy)
 
 	return 0;
 clock_disable:
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 	return ret;
 }

@@ -406,6 +410,7 @@ static int mixel_dphy_power_off(struct phy *phy)
 	phy_write(phy, PWR_OFF, DPHY_PD_PLL);
 	phy_write(phy, PWR_OFF, DPHY_PD_DPHY);
 
+	pm_runtime_put(priv->dev);
 	clk_disable_unprepare(priv->phy_ref_clk);
 
 	return 0;

@@ -467,6 +472,7 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	dev_dbg(dev, "phy_ref clock rate: %lu\n",
 		clk_get_rate(priv->phy_ref_clk));
 
+	priv->dev = dev;
 	dev_set_drvdata(dev, priv);
 
 	phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);

@@ -477,12 +483,26 @@ static int mixel_dphy_probe(struct platform_device *pdev)
 	phy_set_drvdata(phy, priv);
 
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(phy_provider))
+		return PTR_ERR(phy_provider);
 

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 489

Quoted 2 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -1

-	return PTR_ERR_OR_ZERO(phy_provider);
+	pm_runtime_enable(dev);

If this enablement is done prior to devm_phy_create(), then the phy-core will manage runtime PM for this device. This way, this driver doesn't have to manage it by itself.

Regards,
Liu Ying

Quoted 13 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +11 -0

+
+	return 0;
+}
+
+static int mixel_dphy_remove(struct platform_device *pdev)
+{
+	struct mixel_dphy_priv *priv = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(priv->dev);
+
+	return 0;
 }
 

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c static int mixel_dphy_probe(struct platform_device *pdev) · line 508

Quoted 6 lines

drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c +1 -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,