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.h>
9 #include <linux/platform_device.h>
10 #include <linux/reset-controller.h>
11 #include <linux/spinlock.h>
12
13 #include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
14
15 struct meson_audio_arb_data {
16 struct reset_controller_dev rstc;
17 void __iomem *regs;
18 struct clk *clk;
19 const unsigned int *reset_bits;
20 spinlock_t lock;
21 };
22
23 struct meson_audio_arb_match_data {
24 const unsigned int *reset_bits;
25 unsigned int reset_num;
26 };
27
28 #define ARB_GENERAL_BIT 31
29
30 static const unsigned int axg_audio_arb_reset_bits[] = {
31 [AXG_ARB_TODDR_A] = 0,
32 [AXG_ARB_TODDR_B] = 1,
33 [AXG_ARB_TODDR_C] = 2,
34 [AXG_ARB_FRDDR_A] = 4,
35 [AXG_ARB_FRDDR_B] = 5,
36 [AXG_ARB_FRDDR_C] = 6,
37 };
38
39 static const struct meson_audio_arb_match_data axg_audio_arb_match = {
40 .reset_bits = axg_audio_arb_reset_bits,
41 .reset_num = ARRAY_SIZE(axg_audio_arb_reset_bits),
42 };
43
44 static const unsigned int sm1_audio_arb_reset_bits[] = {
45 [AXG_ARB_TODDR_A] = 0,
46 [AXG_ARB_TODDR_B] = 1,
47 [AXG_ARB_TODDR_C] = 2,
48 [AXG_ARB_FRDDR_A] = 4,
49 [AXG_ARB_FRDDR_B] = 5,
50 [AXG_ARB_FRDDR_C] = 6,
51 [AXG_ARB_TODDR_D] = 3,
52 [AXG_ARB_FRDDR_D] = 7,
53 };
54
55 static const struct meson_audio_arb_match_data sm1_audio_arb_match = {
56 .reset_bits = sm1_audio_arb_reset_bits,
57 .reset_num = ARRAY_SIZE(sm1_audio_arb_reset_bits),
58 };
59
meson_audio_arb_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)60 static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
61 unsigned long id, bool assert)
62 {
63 u32 val;
64 struct meson_audio_arb_data *arb =
65 container_of(rcdev, struct meson_audio_arb_data, rstc);
66
67 spin_lock(&arb->lock);
68 val = readl(arb->regs);
69
70 if (assert)
71 val &= ~BIT(arb->reset_bits[id]);
72 else
73 val |= BIT(arb->reset_bits[id]);
74
75 writel(val, arb->regs);
76 spin_unlock(&arb->lock);
77
78 return 0;
79 }
80
meson_audio_arb_status(struct reset_controller_dev * rcdev,unsigned long id)81 static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
82 unsigned long id)
83 {
84 u32 val;
85 struct meson_audio_arb_data *arb =
86 container_of(rcdev, struct meson_audio_arb_data, rstc);
87
88 val = readl(arb->regs);
89
90 return !(val & BIT(arb->reset_bits[id]));
91 }
92
meson_audio_arb_assert(struct reset_controller_dev * rcdev,unsigned long id)93 static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
94 unsigned long id)
95 {
96 return meson_audio_arb_update(rcdev, id, true);
97 }
98
meson_audio_arb_deassert(struct reset_controller_dev * rcdev,unsigned long id)99 static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
100 unsigned long id)
101 {
102 return meson_audio_arb_update(rcdev, id, false);
103 }
104
105 static const struct reset_control_ops meson_audio_arb_rstc_ops = {
106 .assert = meson_audio_arb_assert,
107 .deassert = meson_audio_arb_deassert,
108 .status = meson_audio_arb_status,
109 };
110
111 static const struct of_device_id meson_audio_arb_of_match[] = {
112 {
113 .compatible = "amlogic,meson-axg-audio-arb",
114 .data = &axg_audio_arb_match,
115 }, {
116 .compatible = "amlogic,meson-sm1-audio-arb",
117 .data = &sm1_audio_arb_match,
118 },
119 {}
120 };
121 MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
122
meson_audio_arb_remove(struct platform_device * pdev)123 static void meson_audio_arb_remove(struct platform_device *pdev)
124 {
125 struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
126
127 /* Disable all access */
128 spin_lock(&arb->lock);
129 writel(0, arb->regs);
130 spin_unlock(&arb->lock);
131 }
132
meson_audio_arb_probe(struct platform_device * pdev)133 static int meson_audio_arb_probe(struct platform_device *pdev)
134 {
135 struct device *dev = &pdev->dev;
136 const struct meson_audio_arb_match_data *data;
137 struct meson_audio_arb_data *arb;
138 int ret;
139
140 data = of_device_get_match_data(dev);
141 if (!data)
142 return -EINVAL;
143
144 arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
145 if (!arb)
146 return -ENOMEM;
147 platform_set_drvdata(pdev, arb);
148
149 arb->clk = devm_clk_get_enabled(dev, NULL);
150 if (IS_ERR(arb->clk))
151 return dev_err_probe(dev, PTR_ERR(arb->clk), "failed to get clock\n");
152
153 arb->regs = devm_platform_ioremap_resource(pdev, 0);
154 if (IS_ERR(arb->regs))
155 return PTR_ERR(arb->regs);
156
157 spin_lock_init(&arb->lock);
158 arb->reset_bits = data->reset_bits;
159 arb->rstc.nr_resets = data->reset_num;
160 arb->rstc.ops = &meson_audio_arb_rstc_ops;
161 arb->rstc.of_node = dev->of_node;
162 arb->rstc.owner = THIS_MODULE;
163
164 /*
165 * Enable general :
166 * In the initial state, all memory interfaces are disabled
167 * and the general bit is on
168 */
169 writel(BIT(ARB_GENERAL_BIT), arb->regs);
170
171 /* Register reset controller */
172 ret = devm_reset_controller_register(dev, &arb->rstc);
173 if (ret) {
174 dev_err(dev, "failed to register arb reset controller\n");
175 meson_audio_arb_remove(pdev);
176 }
177
178 return ret;
179 }
180
181 static struct platform_driver meson_audio_arb_pdrv = {
182 .probe = meson_audio_arb_probe,
183 .remove_new = meson_audio_arb_remove,
184 .driver = {
185 .name = "meson-audio-arb-reset",
186 .of_match_table = meson_audio_arb_of_match,
187 },
188 };
189 module_platform_driver(meson_audio_arb_pdrv);
190
191 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
192 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
193 MODULE_LICENSE("GPL v2");
194