u-boot/drivers/reset/reset-uclass.c
Stephen Warren 89c1e2da78 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>
2016-06-19 17:05:55 -06:00

131 lines
2.8 KiB
C

/*
* 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",
};