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03a69568 Z |
1 | /* |
2 | * Rockchip eFuse Driver | |
3 | * | |
4 | * Copyright (c) 2015 Rockchip Electronics Co. Ltd. | |
5 | * Author: Caesar Wang <wxt@rock-chips.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of version 2 of the GNU General Public License as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | */ | |
16 | ||
17 | #include <linux/platform_device.h> | |
18 | #include <linux/nvmem-provider.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/regmap.h> | |
21 | #include <linux/device.h> | |
22 | #include <linux/io.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/delay.h> | |
25 | #include <linux/of.h> | |
26 | #include <linux/clk.h> | |
27 | ||
28 | #define EFUSE_A_SHIFT 6 | |
29 | #define EFUSE_A_MASK 0x3ff | |
30 | #define EFUSE_PGENB BIT(3) | |
31 | #define EFUSE_LOAD BIT(2) | |
32 | #define EFUSE_STROBE BIT(1) | |
33 | #define EFUSE_CSB BIT(0) | |
34 | ||
35 | #define REG_EFUSE_CTRL 0x0000 | |
36 | #define REG_EFUSE_DOUT 0x0004 | |
37 | ||
38 | struct rockchip_efuse_context { | |
39 | struct device *dev; | |
40 | void __iomem *base; | |
41 | struct clk *efuse_clk; | |
42 | }; | |
43 | ||
44 | static int rockchip_efuse_write(void *context, const void *data, size_t count) | |
45 | { | |
46 | /* Nothing TBD, Read-Only */ | |
47 | return 0; | |
48 | } | |
49 | ||
50 | static int rockchip_efuse_read(void *context, | |
51 | const void *reg, size_t reg_size, | |
52 | void *val, size_t val_size) | |
53 | { | |
54 | unsigned int offset = *(u32 *)reg; | |
55 | struct rockchip_efuse_context *_context = context; | |
56 | void __iomem *base = _context->base; | |
57 | struct clk *clk = _context->efuse_clk; | |
58 | u8 *buf = val; | |
59 | int ret; | |
60 | ||
61 | ret = clk_prepare_enable(clk); | |
62 | if (ret < 0) { | |
63 | dev_err(_context->dev, "failed to prepare/enable efuse clk\n"); | |
64 | return ret; | |
65 | } | |
66 | ||
67 | writel(EFUSE_LOAD | EFUSE_PGENB, base + REG_EFUSE_CTRL); | |
68 | udelay(1); | |
69 | while (val_size) { | |
70 | writel(readl(base + REG_EFUSE_CTRL) & | |
71 | (~(EFUSE_A_MASK << EFUSE_A_SHIFT)), | |
72 | base + REG_EFUSE_CTRL); | |
73 | writel(readl(base + REG_EFUSE_CTRL) | | |
74 | ((offset & EFUSE_A_MASK) << EFUSE_A_SHIFT), | |
75 | base + REG_EFUSE_CTRL); | |
76 | udelay(1); | |
77 | writel(readl(base + REG_EFUSE_CTRL) | | |
78 | EFUSE_STROBE, base + REG_EFUSE_CTRL); | |
79 | udelay(1); | |
80 | *buf++ = readb(base + REG_EFUSE_DOUT); | |
81 | writel(readl(base + REG_EFUSE_CTRL) & | |
82 | (~EFUSE_STROBE), base + REG_EFUSE_CTRL); | |
83 | udelay(1); | |
84 | ||
85 | val_size -= 1; | |
86 | offset += 1; | |
87 | } | |
88 | ||
89 | /* Switch to standby mode */ | |
90 | writel(EFUSE_PGENB | EFUSE_CSB, base + REG_EFUSE_CTRL); | |
91 | ||
92 | clk_disable_unprepare(clk); | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | static struct regmap_bus rockchip_efuse_bus = { | |
98 | .read = rockchip_efuse_read, | |
99 | .write = rockchip_efuse_write, | |
100 | .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, | |
101 | .val_format_endian_default = REGMAP_ENDIAN_NATIVE, | |
102 | }; | |
103 | ||
104 | struct regmap_config rockchip_efuse_regmap_config = { | |
105 | .reg_bits = 32, | |
106 | .reg_stride = 1, | |
107 | .val_bits = 8, | |
108 | }; | |
109 | ||
110 | static struct nvmem_config econfig = { | |
111 | .name = "rockchip-efuse", | |
112 | .owner = THIS_MODULE, | |
113 | .read_only = true, | |
114 | }; | |
115 | ||
116 | static const struct of_device_id rockchip_efuse_match[] = { | |
117 | { .compatible = "rockchip,rockchip-efuse",}, | |
118 | { /* sentinel */}, | |
119 | }; | |
120 | MODULE_DEVICE_TABLE(of, rockchip_efuse_match); | |
121 | ||
122 | int rockchip_efuse_probe(struct platform_device *pdev) | |
123 | { | |
124 | struct device *dev = &pdev->dev; | |
125 | struct resource *res; | |
126 | struct nvmem_device *nvmem; | |
127 | struct regmap *regmap; | |
128 | void __iomem *base; | |
129 | struct clk *clk; | |
130 | struct rockchip_efuse_context *context; | |
131 | ||
132 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
133 | base = devm_ioremap_resource(dev, res); | |
134 | if (IS_ERR(base)) | |
135 | return PTR_ERR(base); | |
136 | ||
137 | context = devm_kzalloc(dev, sizeof(struct rockchip_efuse_context), | |
138 | GFP_KERNEL); | |
139 | if (IS_ERR(context)) | |
140 | return PTR_ERR(context); | |
141 | ||
142 | clk = devm_clk_get(dev, "pclk_efuse"); | |
143 | if (IS_ERR(clk)) | |
144 | return PTR_ERR(clk); | |
145 | ||
146 | context->dev = dev; | |
147 | context->base = base; | |
148 | context->efuse_clk = clk; | |
149 | ||
150 | rockchip_efuse_regmap_config.max_register = resource_size(res) - 1; | |
151 | ||
152 | regmap = devm_regmap_init(dev, &rockchip_efuse_bus, | |
153 | context, &rockchip_efuse_regmap_config); | |
154 | if (IS_ERR(regmap)) { | |
155 | dev_err(dev, "regmap init failed\n"); | |
156 | return PTR_ERR(regmap); | |
157 | } | |
158 | econfig.dev = dev; | |
159 | nvmem = nvmem_register(&econfig); | |
160 | if (IS_ERR(nvmem)) | |
161 | return PTR_ERR(nvmem); | |
162 | ||
163 | platform_set_drvdata(pdev, nvmem); | |
164 | ||
165 | return 0; | |
166 | } | |
167 | ||
168 | int rockchip_efuse_remove(struct platform_device *pdev) | |
169 | { | |
170 | struct nvmem_device *nvmem = platform_get_drvdata(pdev); | |
171 | ||
172 | return nvmem_unregister(nvmem); | |
173 | } | |
174 | ||
175 | static struct platform_driver rockchip_efuse_driver = { | |
176 | .probe = rockchip_efuse_probe, | |
177 | .remove = rockchip_efuse_remove, | |
178 | .driver = { | |
179 | .name = "rockchip-efuse", | |
180 | .of_match_table = rockchip_efuse_match, | |
181 | }, | |
182 | }; | |
183 | ||
184 | module_platform_driver(rockchip_efuse_driver); | |
185 | MODULE_DESCRIPTION("rockchip_efuse driver"); | |
186 | MODULE_LICENSE("GPL v2"); |