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 
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 
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 
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 
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 
123 static int 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 	clk_disable_unprepare(arb->clk);
133 
134 	return 0;
135 }
136 
137 static int meson_audio_arb_probe(struct platform_device *pdev)
138 {
139 	struct device *dev = &pdev->dev;
140 	const struct meson_audio_arb_match_data *data;
141 	struct meson_audio_arb_data *arb;
142 	struct resource *res;
143 	int ret;
144 
145 	data = of_device_get_match_data(dev);
146 	if (!data)
147 		return -EINVAL;
148 
149 	arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
150 	if (!arb)
151 		return -ENOMEM;
152 	platform_set_drvdata(pdev, arb);
153 
154 	arb->clk = devm_clk_get(dev, NULL);
155 	if (IS_ERR(arb->clk))
156 		return dev_err_probe(dev, PTR_ERR(arb->clk), "failed to get clock\n");
157 
158 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
159 	arb->regs = devm_ioremap_resource(dev, res);
160 	if (IS_ERR(arb->regs))
161 		return PTR_ERR(arb->regs);
162 
163 	spin_lock_init(&arb->lock);
164 	arb->reset_bits = data->reset_bits;
165 	arb->rstc.nr_resets = data->reset_num;
166 	arb->rstc.ops = &meson_audio_arb_rstc_ops;
167 	arb->rstc.of_node = dev->of_node;
168 	arb->rstc.owner = THIS_MODULE;
169 
170 	/*
171 	 * Enable general :
172 	 * In the initial state, all memory interfaces are disabled
173 	 * and the general bit is on
174 	 */
175 	ret = clk_prepare_enable(arb->clk);
176 	if (ret) {
177 		dev_err(dev, "failed to enable arb clock\n");
178 		return ret;
179 	}
180 	writel(BIT(ARB_GENERAL_BIT), arb->regs);
181 
182 	/* Register reset controller */
183 	ret = devm_reset_controller_register(dev, &arb->rstc);
184 	if (ret) {
185 		dev_err(dev, "failed to register arb reset controller\n");
186 		meson_audio_arb_remove(pdev);
187 	}
188 
189 	return ret;
190 }
191 
192 static struct platform_driver meson_audio_arb_pdrv = {
193 	.probe = meson_audio_arb_probe,
194 	.remove = meson_audio_arb_remove,
195 	.driver = {
196 		.name = "meson-audio-arb-reset",
197 		.of_match_table = meson_audio_arb_of_match,
198 	},
199 };
200 module_platform_driver(meson_audio_arb_pdrv);
201 
202 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
203 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
204 MODULE_LICENSE("GPL v2");
205