Add a reset driver framework/uclass
A reset controller is a hardware module that controls reset signals that
affect other hardware modules or chips.
This patch defines a standard API that connects reset clients (i.e. the
drivers for devices affected by reset signals) to drivers for reset
controllers/providers. Initially, DT is the only supported method for
connecting the two.
The DT binding specification (reset.txt) was taken from Linux kernel
v4.5's Documentation/devicetree/bindings/reset/reset.txt.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index f2a137a..f6003a0 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -56,6 +56,8 @@
source "drivers/remoteproc/Kconfig"
+source "drivers/reset/Kconfig"
+
source "drivers/rtc/Kconfig"
source "drivers/serial/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index db5317c..1723958 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -68,6 +68,7 @@
obj-y += mailbox/
obj-y += memory/
obj-y += pwm/
+obj-y += reset/
obj-y += input/
# SOC specific infrastructure drivers.
obj-y += soc/
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
new file mode 100644
index 0000000..5c449a9
--- /dev/null
+++ b/drivers/reset/Kconfig
@@ -0,0 +1,15 @@
+menu "Reset Controller Support"
+
+config DM_RESET
+ bool "Enable reset controllers using Driver Model"
+ depends on DM && OF_CONTROL
+ help
+ Enable support for the reset controller driver class. Many hardware
+ modules are equipped with a reset signal, typically driven by some
+ reset controller hardware module within the chip. In U-Boot, reset
+ controller drivers allow control over these reset signals. In some
+ cases this API is applicable to chips outside the CPU as well,
+ although driving such reset isgnals using GPIOs may be more
+ appropriate in this case.
+
+endmenu
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
new file mode 100644
index 0000000..508608e
--- /dev/null
+++ b/drivers/reset/Makefile
@@ -0,0 +1,5 @@
+# Copyright (c) 2016, NVIDIA CORPORATION.
+#
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_DM_RESET) += reset-uclass.o
diff --git a/drivers/reset/reset-uclass.c b/drivers/reset/reset-uclass.c
new file mode 100644
index 0000000..edaecfb
--- /dev/null
+++ b/drivers/reset/reset-uclass.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <reset.h>
+#include <reset-uclass.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static inline struct reset_ops *reset_dev_ops(struct udevice *dev)
+{
+ return (struct reset_ops *)dev->driver->ops;
+}
+
+static int reset_of_xlate_default(struct reset_ctl *reset_ctl,
+ struct fdtdec_phandle_args *args)
+{
+ debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
+
+ if (args->args_count != 1) {
+ debug("Invaild args_count: %d\n", args->args_count);
+ return -EINVAL;
+ }
+
+ reset_ctl->id = args->args[0];
+
+ return 0;
+}
+
+int reset_get_by_index(struct udevice *dev, int index,
+ struct reset_ctl *reset_ctl)
+{
+ struct fdtdec_phandle_args args;
+ int ret;
+ struct udevice *dev_reset;
+ struct reset_ops *ops;
+
+ debug("%s(dev=%p, index=%d, reset_ctl=%p)\n", __func__, dev, index,
+ reset_ctl);
+
+ ret = fdtdec_parse_phandle_with_args(gd->fdt_blob, dev->of_offset,
+ "resets", "#reset-cells", 0,
+ index, &args);
+ if (ret) {
+ debug("%s: fdtdec_parse_phandle_with_args failed: %d\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = uclass_get_device_by_of_offset(UCLASS_RESET, args.node,
+ &dev_reset);
+ if (ret) {
+ debug("%s: uclass_get_device_by_of_offset failed: %d\n",
+ __func__, ret);
+ return ret;
+ }
+ ops = reset_dev_ops(dev_reset);
+
+ reset_ctl->dev = dev_reset;
+ if (ops->of_xlate)
+ ret = ops->of_xlate(reset_ctl, &args);
+ else
+ ret = reset_of_xlate_default(reset_ctl, &args);
+ if (ret) {
+ debug("of_xlate() failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ops->request(reset_ctl);
+ if (ret) {
+ debug("ops->request() failed: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+int reset_get_by_name(struct udevice *dev, const char *name,
+ struct reset_ctl *reset_ctl)
+{
+ int index;
+
+ debug("%s(dev=%p, name=%s, reset_ctl=%p)\n", __func__, dev, name,
+ reset_ctl);
+
+ index = fdt_find_string(gd->fdt_blob, dev->of_offset, "reset-names",
+ name);
+ if (index < 0) {
+ debug("fdt_find_string() failed: %d\n", index);
+ return index;
+ }
+
+ return reset_get_by_index(dev, index, reset_ctl);
+}
+
+int reset_free(struct reset_ctl *reset_ctl)
+{
+ struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
+
+ return ops->free(reset_ctl);
+}
+
+int reset_assert(struct reset_ctl *reset_ctl)
+{
+ struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
+
+ return ops->rst_assert(reset_ctl);
+}
+
+int reset_deassert(struct reset_ctl *reset_ctl)
+{
+ struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
+
+ return ops->rst_deassert(reset_ctl);
+}
+
+UCLASS_DRIVER(reset) = {
+ .id = UCLASS_RESET,
+ .name = "reset",
+};