misc: implement Tegra CAR core driver

The Tegra CAR (Clock And Reset) module provides control of most clocks
and reset signals within the Tegra SoC. This change implements a driver
for this module. However, since the module implements multiple kinds of
services (clocks, resets, perhaps more), all this driver does is bind
various sub-devices, which in turn provide the real services. This driver
is essentially an "MFD" (Multi-Function Device) in Linux kernel speak.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

drivers/misc/Kconfig

@@ -129,6 +129,13 @@ config PCA9551_I2C_ADDR
 	help
 	  The I2C address of the PCA9551 LED controller.
 
+config TEGRA_CAR
+	bool "Enable support for the Tegra CAR driver"
+	depends on TEGRA_NO_BPMP
+	help
+	  The Tegra CAR (Clock and Reset Controller) is a HW module that
+	  controls almost all clocks and resets in a Tegra SoC.
+
 config TEGRA186_BPMP
 	bool "Enable support for the Tegra186 BPMP driver"
 	depends on TEGRA186

drivers/misc/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_SANDBOX) += spltest_sandbox.o
 endif
 endif
 obj-$(CONFIG_SANDBOX) += syscon_sandbox.o
+obj-$(CONFIG_TEGRA_CAR) += tegra_car.o
 obj-$(CONFIG_TEGRA186_BPMP) += tegra186_bpmp.o
 obj-$(CONFIG_TWL4030_LED) += twl4030_led.o
 obj-$(CONFIG_FSL_IFC) += fsl_ifc.o

drivers/misc/tegra_car.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+/**
+ * The CAR exposes multiple different services. We create a sub-device for
+ * each separate type of service, since each device must be of the appropriate
+ * UCLASS.
+ */
+static int tegra_car_bpmp_bind(struct udevice *dev)
+{
+	int ret;
+	struct udevice *child;
+
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	ret = device_bind_driver_to_node(dev, "tegra_car_clk", "tegra_car_clk",
+					 dev->of_offset, &child);
+	if (ret)
+		return ret;
+
+	ret = device_bind_driver_to_node(dev, "tegra_car_reset",
+					 "tegra_car_reset", dev->of_offset,
+					 &child);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int tegra_car_bpmp_probe(struct udevice *dev)
+{
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	return 0;
+}
+
+static int tegra_car_bpmp_remove(struct udevice *dev)
+{
+	debug("%s(dev=%p)\n", __func__, dev);
+
+	return 0;
+}
+
+static const struct udevice_id tegra_car_bpmp_ids[] = {
+	{ .compatible = "nvidia,tegra20-car" },
+	{ .compatible = "nvidia,tegra30-car" },
+	{ .compatible = "nvidia,tegra114-car" },
+	{ .compatible = "nvidia,tegra124-car" },
+	{ .compatible = "nvidia,tegra210-car" },
+	{ }
+};
+
+U_BOOT_DRIVER(tegra_car_bpmp) = {
+	.name		= "tegra_car",
+	.id		= UCLASS_MISC,
+	.of_match	= tegra_car_bpmp_ids,
+	.bind		= tegra_car_bpmp_bind,
+	.probe		= tegra_car_bpmp_probe,
+	.remove		= tegra_car_bpmp_remove,
+};