memory: tegra: Support DVFS on Tegra186 and later

Add a Tegra186 (and later) EMC driver that reads the EMC DVFS tables
from BPMP and uses the EMC clock to change the external memory clock.

This currently only provides a debugfs interface to show the available
frequencies and set lower and upper limits of the allowed range. This
can be used for testing the various frequencies. The goal is to
eventually integrate this with the interconnect framework so that the
EMC frequency can be scaled based on demand from memory clients.

Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/memory/tegra/tegra186.c b/drivers/memory/tegra/tegra186.c
index 77a313f1bf0e..fe23c4f71f13 100644
--- a/drivers/memory/tegra/tegra186.c
+++ b/drivers/memory/tegra/tegra186.c
@@ -590,10 +590,23 @@ static int tegra186_mc_probe(struct platform_device *pdev)
 
 	mc->dev = &pdev->dev;
 
+	err = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
+	if (err < 0)
+		return err;
+
 	platform_set_drvdata(pdev, mc);
 	tegra186_mc_program_sid(mc);
 
-	return err;
+	return 0;
+}
+
+static int tegra186_mc_remove(struct platform_device *pdev)
+{
+	struct tegra186_mc *mc = platform_get_drvdata(pdev);
+
+	of_platform_depopulate(mc->dev);
+
+	return 0;
 }
 
 static const struct of_device_id tegra186_mc_of_match[] = {
@@ -627,8 +640,8 @@ static struct platform_driver tegra186_mc_driver = {
 		.pm = &tegra186_mc_pm_ops,
 		.suppress_bind_attrs = true,
 	},
-	.prevent_deferred_probe = true,
 	.probe = tegra186_mc_probe,
+	.remove = tegra186_mc_remove,
 };
 module_platform_driver(tegra186_mc_driver);