dm: Add support for simple-pm-bus
This type of bus is used in Linux to designate buses which have power
domains and/or clocks which need to be enabled before their child devices
can be used. Because power domains are automatically enabled before probing
in U-Boot, we just need to enable any clocks present.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/simple-pm-bus.c b/drivers/core/simple-pm-bus.c
new file mode 100644
index 0000000..51dc9b2
--- /dev/null
+++ b/drivers/core/simple-pm-bus.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+
+/*
+ * Power domains are taken care of by driver_probe, so we just have to enable
+ * clocks
+ */
+static int simple_pm_bus_probe(struct udevice *dev)
+{
+ int ret;
+ struct clk_bulk *bulk = dev_get_priv(dev);
+
+ ret = clk_get_bulk(dev, bulk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable_bulk(bulk);
+ if (ret && ret != -ENOSYS && ret != -ENOTSUPP) {
+ clk_release_bulk(bulk);
+ return ret;
+ }
+ return 0;
+}
+
+static int simple_pm_bus_remove(struct udevice *dev)
+{
+ int ret;
+ struct clk_bulk *bulk = dev_get_priv(dev);
+
+ ret = clk_release_bulk(bulk);
+ if (ret && ret != -ENOSYS && ret != -ENOTSUPP)
+ return ret;
+ else
+ return 0;
+}
+
+static const struct udevice_id simple_pm_bus_ids[] = {
+ { .compatible = "simple-pm-bus" },
+ { }
+};
+
+U_BOOT_DRIVER(simple_pm_bus_drv) = {
+ .name = "simple_pm_bus",
+ .id = UCLASS_SIMPLE_BUS,
+ .of_match = simple_pm_bus_ids,
+ .probe = simple_pm_bus_probe,
+ .remove = simple_pm_bus_remove,
+ .priv_auto_alloc_size = sizeof(struct clk_bulk),
+ .flags = DM_FLAG_PRE_RELOC,
+};