1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Amlogic Meson GX eFuse Driver
4 *
5 * Copyright (c) 2016 Endless Computers, Inc.
6 * Author: Carlo Caione <carlo@endlessm.com>
7 */
8
9#include <linux/clk.h>
10#include <linux/module.h>
11#include <linux/nvmem-provider.h>
12#include <linux/of.h>
13#include <linux/platform_device.h>
14
15#include <linux/firmware/meson/meson_sm.h>
16
17static int meson_efuse_read(void *context, unsigned int offset,
18			    void *val, size_t bytes)
19{
20	struct meson_sm_firmware *fw = context;
21
22	return meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
23				  bytes, 0, 0, 0);
24}
25
26static int meson_efuse_write(void *context, unsigned int offset,
27			     void *val, size_t bytes)
28{
29	struct meson_sm_firmware *fw = context;
30
31	return meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
32				   bytes, 0, 0, 0);
33}
34
35static const struct of_device_id meson_efuse_match[] = {
36	{ .compatible = "amlogic,meson-gxbb-efuse", },
37	{ /* sentinel */ },
38};
39MODULE_DEVICE_TABLE(of, meson_efuse_match);
40
41static int meson_efuse_probe(struct platform_device *pdev)
42{
43	struct device *dev = &pdev->dev;
44	struct meson_sm_firmware *fw;
45	struct device_node *sm_np;
46	struct nvmem_device *nvmem;
47	struct nvmem_config *econfig;
48	struct clk *clk;
49	unsigned int size;
50	int ret;
51
52	sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
53	if (!sm_np) {
54		dev_err(&pdev->dev, "no secure-monitor node\n");
55		return -ENODEV;
56	}
57
58	fw = meson_sm_get(sm_np);
59	of_node_put(sm_np);
60	if (!fw)
61		return -EPROBE_DEFER;
62
63	clk = devm_clk_get(dev, NULL);
64	if (IS_ERR(clk)) {
65		ret = PTR_ERR(clk);
66		if (ret != -EPROBE_DEFER)
67			dev_err(dev, "failed to get efuse gate");
68		return ret;
69	}
70
71	ret = clk_prepare_enable(clk);
72	if (ret) {
73		dev_err(dev, "failed to enable gate");
74		return ret;
75	}
76
77	ret = devm_add_action_or_reset(dev,
78				       (void(*)(void *))clk_disable_unprepare,
79				       clk);
80	if (ret) {
81		dev_err(dev, "failed to add disable callback");
82		return ret;
83	}
84
85	if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
86		dev_err(dev, "failed to get max user");
87		return -EINVAL;
88	}
89
90	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
91	if (!econfig)
92		return -ENOMEM;
93
94	econfig->dev = dev;
95	econfig->name = dev_name(dev);
96	econfig->stride = 1;
97	econfig->word_size = 1;
98	econfig->reg_read = meson_efuse_read;
99	econfig->reg_write = meson_efuse_write;
100	econfig->size = size;
101	econfig->priv = fw;
102
103	nvmem = devm_nvmem_register(&pdev->dev, econfig);
104
105	return PTR_ERR_OR_ZERO(nvmem);
106}
107
108static struct platform_driver meson_efuse_driver = {
109	.probe = meson_efuse_probe,
110	.driver = {
111		.name = "meson-efuse",
112		.of_match_table = meson_efuse_match,
113	},
114};
115
116module_platform_driver(meson_efuse_driver);
117
118MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
119MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
120MODULE_LICENSE("GPL v2");
121