reset-meson.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Amlogic Meson Reset Controller driver
*
* Copyright (c) 2018 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
*/
#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <reset-uclass.h>
#include <regmap.h>
#define REG_COUNT 8
#define BITS_PER_REG 32
#define LEVEL_OFFSET 0x7c
struct meson_reset_priv {
struct regmap *regmap;
};
static int meson_reset_request(struct reset_ctl *reset_ctl)
{
if (reset_ctl->id > (REG_COUNT * BITS_PER_REG))
return -EINVAL;
return 0;
}
static int meson_reset_free(struct reset_ctl *reset_ctl)
{
return 0;
}
static int meson_reset_level(struct reset_ctl *reset_ctl, bool assert)
{
struct meson_reset_priv *priv = dev_get_priv(reset_ctl->dev);
uint bank = reset_ctl->id / BITS_PER_REG;
uint offset = reset_ctl->id % BITS_PER_REG;
uint reg_offset = LEVEL_OFFSET + (bank << 2);
uint val;
regmap_read(priv->regmap, reg_offset, &val);
if (assert)
val &= ~BIT(offset);
else
val |= BIT(offset);
regmap_write(priv->regmap, reg_offset, val);
return 0;
}
static int meson_reset_assert(struct reset_ctl *reset_ctl)
{
return meson_reset_level(reset_ctl, true);
}
static int meson_reset_deassert(struct reset_ctl *reset_ctl)
{
return meson_reset_level(reset_ctl, false);
}
struct reset_ops meson_reset_ops = {
.request = meson_reset_request,
.rfree = meson_reset_free,
.rst_assert = meson_reset_assert,
.rst_deassert = meson_reset_deassert,
};
static const struct udevice_id meson_reset_ids[] = {
{ .compatible = "amlogic,meson-gxbb-reset" },
{ .compatible = "amlogic,meson-axg-reset" },
{ }
};
static int meson_reset_probe(struct udevice *dev)
{
struct meson_reset_priv *priv = dev_get_priv(dev);
return regmap_init_mem(dev_ofnode(dev), &priv->regmap);
}
U_BOOT_DRIVER(meson_reset) = {
.name = "meson_reset",
.id = UCLASS_RESET,
.of_match = meson_reset_ids,
.probe = meson_reset_probe,
.ops = &meson_reset_ops,
.priv_auto_alloc_size = sizeof(struct meson_reset_priv),
};