soc/tegra: fuse: Add runtime PM support

The Tegra FUSE belongs to the core power domain and we're going to enable
GENPD support for the core domain. Now FUSE device must be resumed using
runtime PM API in order to initialize the FUSE power state. Add runtime PM
support to the FUSE driver.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/soc/tegra/fuse/fuse-tegra.c

@@ -13,6 +13,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
 
@@ -210,6 +211,8 @@ static int tegra_fuse_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, fuse);
 	fuse->dev = &pdev->dev;
 
+	pm_runtime_enable(&pdev->dev);
+
 	if (fuse->soc->probe) {
 		err = fuse->soc->probe(fuse);
 		if (err < 0)
@@ -248,13 +251,40 @@ static int tegra_fuse_probe(struct platform_device *pdev)
 restore:
 	fuse->clk = NULL;
 	fuse->base = base;
+	pm_runtime_disable(&pdev->dev);
 	return err;
 }
 
+static int __maybe_unused tegra_fuse_runtime_resume(struct device *dev)
+{
+	int err;
+
+	err = clk_prepare_enable(fuse->clk);
+	if (err < 0) {
+		dev_err(dev, "failed to enable FUSE clock: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused tegra_fuse_runtime_suspend(struct device *dev)
+{
+	clk_disable_unprepare(fuse->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_fuse_pm = {
+	SET_RUNTIME_PM_OPS(tegra_fuse_runtime_suspend, tegra_fuse_runtime_resume,
+			   NULL)
+};
+
 static struct platform_driver tegra_fuse_driver = {
 	.driver = {
 		.name = "tegra-fuse",
 		.of_match_table = tegra_fuse_match,
+		.pm = &tegra_fuse_pm,
 		.suppress_bind_attrs = true,
 	},
 	.probe = tegra_fuse_probe,

drivers/soc/tegra/fuse/fuse-tegra20.c

@@ -16,6 +16,7 @@
 #include <linux/kobject.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/random.h>
 
 #include <soc/tegra/fuse.h>
@@ -46,6 +47,10 @@ static u32 tegra20_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
 	u32 value = 0;
 	int err;
 
+	err = pm_runtime_resume_and_get(fuse->dev);
+	if (err)
+		return err;
+
 	mutex_lock(&fuse->apbdma.lock);
 
 	fuse->apbdma.config.src_addr = fuse->phys + FUSE_BEGIN + offset;
@@ -66,8 +71,6 @@ static u32 tegra20_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
 
 	reinit_completion(&fuse->apbdma.wait);
 
-	clk_prepare_enable(fuse->clk);
-
 	dmaengine_submit(dma_desc);
 	dma_async_issue_pending(fuse->apbdma.chan);
 	time_left = wait_for_completion_timeout(&fuse->apbdma.wait,
@@ -78,10 +81,9 @@ static u32 tegra20_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
 	else
 		value = *fuse->apbdma.virt;
 
-	clk_disable_unprepare(fuse->clk);
-
 out:
 	mutex_unlock(&fuse->apbdma.lock);
+	pm_runtime_put(fuse->dev);
 	return value;
 }
 

drivers/soc/tegra/fuse/fuse-tegra30.c

@@ -12,6 +12,7 @@
 #include <linux/of_device.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/random.h>
 
 #include <soc/tegra/fuse.h>
@@ -52,15 +53,13 @@ static u32 tegra30_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
 	u32 value;
 	int err;
 
-	err = clk_prepare_enable(fuse->clk);
-	if (err < 0) {
-		dev_err(fuse->dev, "failed to enable FUSE clock: %d\n", err);
+	err = pm_runtime_resume_and_get(fuse->dev);
+	if (err)
 		return 0;
-	}
 
 	value = readl_relaxed(fuse->base + FUSE_BEGIN + offset);
 
-	clk_disable_unprepare(fuse->clk);
+	pm_runtime_put(fuse->dev);
 
 	return value;
 }