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Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: (GPL-2.0 OR MIT)
2// Copyright (c) 2018 BayLibre, SAS.
3// Author: Jerome Brunet <jbrunet@baylibre.com>
4
5#include <linux/clk.h>
6#include <linux/io.h>
7#include <linux/module.h>
8#include <linux/of_platform.h>
9#include <linux/reset-controller.h>
10#include <linux/spinlock.h>
11
12#include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
13
14struct meson_audio_arb_data {
15 struct reset_controller_dev rstc;
16 void __iomem *regs;
17 struct clk *clk;
18 const unsigned int *reset_bits;
19 spinlock_t lock;
20};
21
22#define ARB_GENERAL_BIT 31
23
24static const unsigned int axg_audio_arb_reset_bits[] = {
25 [AXG_ARB_TODDR_A] = 0,
26 [AXG_ARB_TODDR_B] = 1,
27 [AXG_ARB_TODDR_C] = 2,
28 [AXG_ARB_FRDDR_A] = 4,
29 [AXG_ARB_FRDDR_B] = 5,
30 [AXG_ARB_FRDDR_C] = 6,
31};
32
33static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
34 unsigned long id, bool assert)
35{
36 u32 val;
37 struct meson_audio_arb_data *arb =
38 container_of(rcdev, struct meson_audio_arb_data, rstc);
39
40 spin_lock(&arb->lock);
41 val = readl(arb->regs);
42
43 if (assert)
44 val &= ~BIT(arb->reset_bits[id]);
45 else
46 val |= BIT(arb->reset_bits[id]);
47
48 writel(val, arb->regs);
49 spin_unlock(&arb->lock);
50
51 return 0;
52}
53
54static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
55 unsigned long id)
56{
57 u32 val;
58 struct meson_audio_arb_data *arb =
59 container_of(rcdev, struct meson_audio_arb_data, rstc);
60
61 val = readl(arb->regs);
62
63 return !(val & BIT(arb->reset_bits[id]));
64}
65
66static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
67 unsigned long id)
68{
69 return meson_audio_arb_update(rcdev, id, true);
70}
71
72static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
73 unsigned long id)
74{
75 return meson_audio_arb_update(rcdev, id, false);
76}
77
78static const struct reset_control_ops meson_audio_arb_rstc_ops = {
79 .assert = meson_audio_arb_assert,
80 .deassert = meson_audio_arb_deassert,
81 .status = meson_audio_arb_status,
82};
83
84static const struct of_device_id meson_audio_arb_of_match[] = {
85 { .compatible = "amlogic,meson-axg-audio-arb", },
86 {}
87};
88MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
89
90static int meson_audio_arb_remove(struct platform_device *pdev)
91{
92 struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
93
94 /* Disable all access */
95 spin_lock(&arb->lock);
96 writel(0, arb->regs);
97 spin_unlock(&arb->lock);
98
99 clk_disable_unprepare(arb->clk);
100
101 return 0;
102}
103
104static int meson_audio_arb_probe(struct platform_device *pdev)
105{
106 struct device *dev = &pdev->dev;
107 struct meson_audio_arb_data *arb;
108 struct resource *res;
109 int ret;
110
111 arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
112 if (!arb)
113 return -ENOMEM;
114 platform_set_drvdata(pdev, arb);
115
116 arb->clk = devm_clk_get(dev, NULL);
117 if (IS_ERR(arb->clk)) {
118 if (PTR_ERR(arb->clk) != -EPROBE_DEFER)
119 dev_err(dev, "failed to get clock\n");
120 return PTR_ERR(arb->clk);
121 }
122
123 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
124 arb->regs = devm_ioremap_resource(dev, res);
125 if (IS_ERR(arb->regs))
126 return PTR_ERR(arb->regs);
127
128 spin_lock_init(&arb->lock);
129 arb->reset_bits = axg_audio_arb_reset_bits;
130 arb->rstc.nr_resets = ARRAY_SIZE(axg_audio_arb_reset_bits);
131 arb->rstc.ops = &meson_audio_arb_rstc_ops;
132 arb->rstc.of_node = dev->of_node;
133 arb->rstc.owner = THIS_MODULE;
134
135 /*
136 * Enable general :
137 * In the initial state, all memory interfaces are disabled
138 * and the general bit is on
139 */
140 ret = clk_prepare_enable(arb->clk);
141 if (ret) {
142 dev_err(dev, "failed to enable arb clock\n");
143 return ret;
144 }
145 writel(BIT(ARB_GENERAL_BIT), arb->regs);
146
147 /* Register reset controller */
148 ret = devm_reset_controller_register(dev, &arb->rstc);
149 if (ret) {
150 dev_err(dev, "failed to register arb reset controller\n");
151 meson_audio_arb_remove(pdev);
152 }
153
154 return ret;
155}
156
157static struct platform_driver meson_audio_arb_pdrv = {
158 .probe = meson_audio_arb_probe,
159 .remove = meson_audio_arb_remove,
160 .driver = {
161 .name = "meson-audio-arb-reset",
162 .of_match_table = meson_audio_arb_of_match,
163 },
164};
165module_platform_driver(meson_audio_arb_pdrv);
166
167MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
168MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
169MODULE_LICENSE("GPL v2");