1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Amlogic Meson Reset Controller driver
4 *
5 * Copyright (c) 2018 BayLibre, SAS.
6 * Author: Neil Armstrong <narmstrong@baylibre.com>
7 */
8
9 #include <common.h>
10 #include <dm.h>
11 #include <log.h>
12 #include <malloc.h>
13 #include <reset-uclass.h>
14 #include <regmap.h>
15 #include <linux/bitops.h>
16
17 #define REG_COUNT 8
18 #define BITS_PER_REG 32
19 #define LEVEL_OFFSET 0x7c
20
21 struct meson_reset_priv {
22 struct regmap *regmap;
23 };
24
meson_reset_request(struct reset_ctl * reset_ctl)25 static int meson_reset_request(struct reset_ctl *reset_ctl)
26 {
27 if (reset_ctl->id > (REG_COUNT * BITS_PER_REG))
28 return -EINVAL;
29
30 return 0;
31 }
32
meson_reset_free(struct reset_ctl * reset_ctl)33 static int meson_reset_free(struct reset_ctl *reset_ctl)
34 {
35 return 0;
36 }
37
meson_reset_level(struct reset_ctl * reset_ctl,bool assert)38 static int meson_reset_level(struct reset_ctl *reset_ctl, bool assert)
39 {
40 struct meson_reset_priv *priv = dev_get_priv(reset_ctl->dev);
41 uint bank = reset_ctl->id / BITS_PER_REG;
42 uint offset = reset_ctl->id % BITS_PER_REG;
43 uint reg_offset = LEVEL_OFFSET + (bank << 2);
44 uint val;
45
46 regmap_read(priv->regmap, reg_offset, &val);
47 if (assert)
48 val &= ~BIT(offset);
49 else
50 val |= BIT(offset);
51 regmap_write(priv->regmap, reg_offset, val);
52
53 return 0;
54 }
55
meson_reset_assert(struct reset_ctl * reset_ctl)56 static int meson_reset_assert(struct reset_ctl *reset_ctl)
57 {
58 return meson_reset_level(reset_ctl, true);
59 }
60
meson_reset_deassert(struct reset_ctl * reset_ctl)61 static int meson_reset_deassert(struct reset_ctl *reset_ctl)
62 {
63 return meson_reset_level(reset_ctl, false);
64 }
65
66 struct reset_ops meson_reset_ops = {
67 .request = meson_reset_request,
68 .rfree = meson_reset_free,
69 .rst_assert = meson_reset_assert,
70 .rst_deassert = meson_reset_deassert,
71 };
72
73 static const struct udevice_id meson_reset_ids[] = {
74 { .compatible = "amlogic,meson-gxbb-reset" },
75 { .compatible = "amlogic,meson-axg-reset" },
76 { }
77 };
78
meson_reset_probe(struct udevice * dev)79 static int meson_reset_probe(struct udevice *dev)
80 {
81 struct meson_reset_priv *priv = dev_get_priv(dev);
82
83 return regmap_init_mem(dev_ofnode(dev), &priv->regmap);
84 }
85
86 U_BOOT_DRIVER(meson_reset) = {
87 .name = "meson_reset",
88 .id = UCLASS_RESET,
89 .of_match = meson_reset_ids,
90 .probe = meson_reset_probe,
91 .ops = &meson_reset_ops,
92 .priv_auto = sizeof(struct meson_reset_priv),
93 };
94