linux-kernel - [PATCH v2 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 16 Dec 2020 12:27:28 +0100
From:   Guido Günther <agx@...xcpu.org>
To:     Kishon Vijay Abraham I <kishon@...com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Robert Chiras <robert.chiras@....com>,
        Sam Ravnborg <sam@...nborg.org>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2 1/1] 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@...oc@0:bus@...00000/30a00300.dphy  unsupported
    /devices/platform/soc@...oc@0:bus@...00000/30a00000.mipi_dsi  suspended

after:

mipi                            off-0
    /devices/platform/soc@...oc@0:bus@...00000/30a00300.dphy  suspended
    /devices/platform/soc@...oc@0:bus@...00000/30a00000.mipi_dsi  suspended

Signed-off-by: Guido Günther <agx@...xcpu.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);
 
 	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);
 
-	return PTR_ERR_OR_ZERO(phy_provider);
+	pm_runtime_enable(dev);
+
+	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,
-- 
2.29.2