[PATCH v8 18/34] bus: tegra-gmi: Add runtime PM and OPP support

[Dmitry Osipenko <digetx@xxxxxxxxx>]

The GMI bus on Tegra belongs to the core power domain and we're going to
enable GENPD support for the core domain. Now GMI must be resumed using
runtime PM API in order to initialize the GMI power state. Add runtime PM
and OPP support to the GMI driver.

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/bus/tegra-gmi.c | 92 ++++++++++++++++++++++++++++++-----------
 1 file changed, 68 insertions(+), 24 deletions(-)

diff --git a/drivers/bus/tegra-gmi.c b/drivers/bus/tegra-gmi.c
index a6570789f7af..51cac6822f20 100644
--- a/drivers/bus/tegra-gmi.c
+++ b/drivers/bus/tegra-gmi.c
@@ -13,8 +13,12 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/pm_opp.h>
+#include <linux/pm_runtime.h>
 #include <linux/reset.h>
 
+#include <soc/tegra/common.h>
+
 #define TEGRA_GMI_CONFIG		0x00
 #define TEGRA_GMI_CONFIG_GO		BIT(31)
 #define TEGRA_GMI_BUS_WIDTH_32BIT	BIT(30)
@@ -54,36 +58,20 @@ static int tegra_gmi_enable(struct tegra_gmi *gmi)
 {
 	int err;
 
-	err = clk_prepare_enable(gmi->clk);
-	if (err < 0) {
-		dev_err(gmi->dev, "failed to enable clock: %d\n", err);
+	pm_runtime_enable(gmi->dev);
+	err = pm_runtime_resume_and_get(gmi->dev);
+	if (err) {
+		pm_runtime_disable(gmi->dev);
 		return err;
 	}
 
-	reset_control_assert(gmi->rst);
-	usleep_range(2000, 4000);
-	reset_control_deassert(gmi->rst);
-
-	writel(gmi->snor_timing0, gmi->base + TEGRA_GMI_TIMING0);
-	writel(gmi->snor_timing1, gmi->base + TEGRA_GMI_TIMING1);
-
-	gmi->snor_config |= TEGRA_GMI_CONFIG_GO;
-	writel(gmi->snor_config, gmi->base + TEGRA_GMI_CONFIG);
-
 	return 0;
 }
 
 static void tegra_gmi_disable(struct tegra_gmi *gmi)
 {
-	u32 config;
-
-	/* stop GMI operation */
-	config = readl(gmi->base + TEGRA_GMI_CONFIG);
-	config &= ~TEGRA_GMI_CONFIG_GO;
-	writel(config, gmi->base + TEGRA_GMI_CONFIG);
-
-	reset_control_assert(gmi->rst);
-	clk_disable_unprepare(gmi->clk);
+	pm_runtime_put(gmi->dev);
+	pm_runtime_disable(gmi->dev);
 }
 
 static int tegra_gmi_parse_dt(struct tegra_gmi *gmi)
@@ -213,6 +201,7 @@ static int tegra_gmi_probe(struct platform_device *pdev)
 	if (!gmi)
 		return -ENOMEM;
 
+	platform_set_drvdata(pdev, gmi);
 	gmi->dev = dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -232,6 +221,10 @@ static int tegra_gmi_probe(struct platform_device *pdev)
 		return PTR_ERR(gmi->rst);
 	}
 
+	err = devm_tegra_core_dev_init_opp_table_simple(&pdev->dev);
+	if (err)
+		return err;
+
 	err = tegra_gmi_parse_dt(gmi);
 	if (err)
 		return err;
@@ -247,8 +240,6 @@ static int tegra_gmi_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	platform_set_drvdata(pdev, gmi);
-
 	return 0;
 }
 
@@ -262,6 +253,58 @@ static int tegra_gmi_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int __maybe_unused tegra_gmi_runtime_resume(struct device *dev)
+{
+	struct tegra_gmi *gmi = dev_get_drvdata(dev);
+	int err;
+
+	err = dev_pm_opp_sync(gmi->dev);
+	if (err) {
+		dev_err(gmi->dev, "failed to sync OPP: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(gmi->clk);
+	if (err < 0) {
+		dev_err(gmi->dev, "failed to enable clock: %d\n", err);
+		return err;
+	}
+
+	reset_control_assert(gmi->rst);
+	usleep_range(2000, 4000);
+	reset_control_deassert(gmi->rst);
+
+	writel(gmi->snor_timing0, gmi->base + TEGRA_GMI_TIMING0);
+	writel(gmi->snor_timing1, gmi->base + TEGRA_GMI_TIMING1);
+
+	gmi->snor_config |= TEGRA_GMI_CONFIG_GO;
+	writel(gmi->snor_config, gmi->base + TEGRA_GMI_CONFIG);
+
+	return 0;
+}
+
+static int __maybe_unused tegra_gmi_runtime_suspend(struct device *dev)
+{
+	struct tegra_gmi *gmi = dev_get_drvdata(dev);
+	u32 config;
+
+	/* stop GMI operation */
+	config = readl(gmi->base + TEGRA_GMI_CONFIG);
+	config &= ~TEGRA_GMI_CONFIG_GO;
+	writel(config, gmi->base + TEGRA_GMI_CONFIG);
+
+	reset_control_assert(gmi->rst);
+
+	clk_disable_unprepare(gmi->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_gmi_pm = {
+	SET_RUNTIME_PM_OPS(tegra_gmi_runtime_suspend, tegra_gmi_runtime_resume,
+			   NULL)
+};
+
 static const struct of_device_id tegra_gmi_id_table[] = {
 	{ .compatible = "nvidia,tegra20-gmi", },
 	{ .compatible = "nvidia,tegra30-gmi", },
@@ -275,6 +318,7 @@ static struct platform_driver tegra_gmi_driver = {
 	.driver = {
 		.name		= "tegra-gmi",
 		.of_match_table	= tegra_gmi_id_table,
+		.pm = &tegra_gmi_pm,
 	},
 };
 module_platform_driver(tegra_gmi_driver);
-- 
2.32.0