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
14 struct 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 struct meson_audio_arb_match_data {
23 const unsigned int *reset_bits;
24 unsigned int reset_num;
25 };
26
27 #define ARB_GENERAL_BIT 31
28
29 static const unsigned int axg_audio_arb_reset_bits[] = {
30 [AXG_ARB_TODDR_A] = 0,
31 [AXG_ARB_TODDR_B] = 1,
32 [AXG_ARB_TODDR_C] = 2,
33 [AXG_ARB_FRDDR_A] = 4,
34 [AXG_ARB_FRDDR_B] = 5,
35 [AXG_ARB_FRDDR_C] = 6,
36 };
37
38 static const struct meson_audio_arb_match_data axg_audio_arb_match = {
39 .reset_bits = axg_audio_arb_reset_bits,
40 .reset_num = ARRAY_SIZE(axg_audio_arb_reset_bits),
41 };
42
43 static const unsigned int sm1_audio_arb_reset_bits[] = {
44 [AXG_ARB_TODDR_A] = 0,
45 [AXG_ARB_TODDR_B] = 1,
46 [AXG_ARB_TODDR_C] = 2,
47 [AXG_ARB_FRDDR_A] = 4,
48 [AXG_ARB_FRDDR_B] = 5,
49 [AXG_ARB_FRDDR_C] = 6,
50 [AXG_ARB_TODDR_D] = 3,
51 [AXG_ARB_FRDDR_D] = 7,
52 };
53
54 static const struct meson_audio_arb_match_data sm1_audio_arb_match = {
55 .reset_bits = sm1_audio_arb_reset_bits,
56 .reset_num = ARRAY_SIZE(sm1_audio_arb_reset_bits),
57 };
58
meson_audio_arb_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)59 static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
60 unsigned long id, bool assert)
61 {
62 u32 val;
63 struct meson_audio_arb_data *arb =
64 container_of(rcdev, struct meson_audio_arb_data, rstc);
65
66 spin_lock(&arb->lock);
67 val = readl(arb->regs);
68
69 if (assert)
70 val &= ~BIT(arb->reset_bits[id]);
71 else
72 val |= BIT(arb->reset_bits[id]);
73
74 writel(val, arb->regs);
75 spin_unlock(&arb->lock);
76
77 return 0;
78 }
79
meson_audio_arb_status(struct reset_controller_dev * rcdev,unsigned long id)80 static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
81 unsigned long id)
82 {
83 u32 val;
84 struct meson_audio_arb_data *arb =
85 container_of(rcdev, struct meson_audio_arb_data, rstc);
86
87 val = readl(arb->regs);
88
89 return !(val & BIT(arb->reset_bits[id]));
90 }
91
meson_audio_arb_assert(struct reset_controller_dev * rcdev,unsigned long id)92 static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
93 unsigned long id)
94 {
95 return meson_audio_arb_update(rcdev, id, true);
96 }
97
meson_audio_arb_deassert(struct reset_controller_dev * rcdev,unsigned long id)98 static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
99 unsigned long id)
100 {
101 return meson_audio_arb_update(rcdev, id, false);
102 }
103
104 static const struct reset_control_ops meson_audio_arb_rstc_ops = {
105 .assert = meson_audio_arb_assert,
106 .deassert = meson_audio_arb_deassert,
107 .status = meson_audio_arb_status,
108 };
109
110 static const struct of_device_id meson_audio_arb_of_match[] = {
111 {
112 .compatible = "amlogic,meson-axg-audio-arb",
113 .data = &axg_audio_arb_match,
114 }, {
115 .compatible = "amlogic,meson-sm1-audio-arb",
116 .data = &sm1_audio_arb_match,
117 },
118 {}
119 };
120 MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
121
meson_audio_arb_remove(struct platform_device * pdev)122 static int meson_audio_arb_remove(struct platform_device *pdev)
123 {
124 struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
125
126 /* Disable all access */
127 spin_lock(&arb->lock);
128 writel(0, arb->regs);
129 spin_unlock(&arb->lock);
130
131 clk_disable_unprepare(arb->clk);
132
133 return 0;
134 }
135
meson_audio_arb_probe(struct platform_device * pdev)136 static int meson_audio_arb_probe(struct platform_device *pdev)
137 {
138 struct device *dev = &pdev->dev;
139 const struct meson_audio_arb_match_data *data;
140 struct meson_audio_arb_data *arb;
141 struct resource *res;
142 int ret;
143
144 data = of_device_get_match_data(dev);
145 if (!data)
146 return -EINVAL;
147
148 arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
149 if (!arb)
150 return -ENOMEM;
151 platform_set_drvdata(pdev, arb);
152
153 arb->clk = devm_clk_get(dev, NULL);
154 if (IS_ERR(arb->clk)) {
155 if (PTR_ERR(arb->clk) != -EPROBE_DEFER)
156 dev_err(dev, "failed to get clock\n");
157 return PTR_ERR(arb->clk);
158 }
159
160 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
161 arb->regs = devm_ioremap_resource(dev, res);
162 if (IS_ERR(arb->regs))
163 return PTR_ERR(arb->regs);
164
165 spin_lock_init(&arb->lock);
166 arb->reset_bits = data->reset_bits;
167 arb->rstc.nr_resets = data->reset_num;
168 arb->rstc.ops = &meson_audio_arb_rstc_ops;
169 arb->rstc.of_node = dev->of_node;
170 arb->rstc.owner = THIS_MODULE;
171
172 /*
173 * Enable general :
174 * In the initial state, all memory interfaces are disabled
175 * and the general bit is on
176 */
177 ret = clk_prepare_enable(arb->clk);
178 if (ret) {
179 dev_err(dev, "failed to enable arb clock\n");
180 return ret;
181 }
182 writel(BIT(ARB_GENERAL_BIT), arb->regs);
183
184 /* Register reset controller */
185 ret = devm_reset_controller_register(dev, &arb->rstc);
186 if (ret) {
187 dev_err(dev, "failed to register arb reset controller\n");
188 meson_audio_arb_remove(pdev);
189 }
190
191 return ret;
192 }
193
194 static struct platform_driver meson_audio_arb_pdrv = {
195 .probe = meson_audio_arb_probe,
196 .remove = meson_audio_arb_remove,
197 .driver = {
198 .name = "meson-audio-arb-reset",
199 .of_match_table = meson_audio_arb_of_match,
200 },
201 };
202 module_platform_driver(meson_audio_arb_pdrv);
203
204 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
205 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
206 MODULE_LICENSE("GPL v2");
207