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1 | /* |
2 | * Freescale MXS On-Chip OTP driver | |
3 | * | |
4 | * Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com> | |
5 | * | |
6 | * Based on the driver from Huang Shijie and Christoph G. Baumann | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | */ | |
19 | #include <linux/clk.h> | |
20 | #include <linux/delay.h> | |
21 | #include <linux/device.h> | |
22 | #include <linux/err.h> | |
23 | #include <linux/io.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/nvmem-provider.h> | |
26 | #include <linux/of_device.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/regmap.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/stmp_device.h> | |
31 | ||
32 | /* OCOTP registers and bits */ | |
33 | ||
34 | #define BM_OCOTP_CTRL_RD_BANK_OPEN BIT(12) | |
35 | #define BM_OCOTP_CTRL_ERROR BIT(9) | |
36 | #define BM_OCOTP_CTRL_BUSY BIT(8) | |
37 | ||
38 | #define OCOTP_TIMEOUT 10000 | |
39 | #define OCOTP_DATA_OFFSET 0x20 | |
40 | ||
41 | struct mxs_ocotp { | |
42 | struct clk *clk; | |
43 | void __iomem *base; | |
44 | struct nvmem_device *nvmem; | |
45 | }; | |
46 | ||
47 | static int mxs_ocotp_wait(struct mxs_ocotp *otp) | |
48 | { | |
49 | int timeout = OCOTP_TIMEOUT; | |
50 | unsigned int status = 0; | |
51 | ||
52 | while (timeout--) { | |
53 | status = readl(otp->base); | |
54 | ||
55 | if (!(status & (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR))) | |
56 | break; | |
57 | ||
58 | cpu_relax(); | |
59 | } | |
60 | ||
61 | if (status & BM_OCOTP_CTRL_BUSY) | |
62 | return -EBUSY; | |
63 | else if (status & BM_OCOTP_CTRL_ERROR) | |
64 | return -EIO; | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int mxs_ocotp_read(void *context, const void *reg, size_t reg_size, | |
70 | void *val, size_t val_size) | |
71 | { | |
72 | struct mxs_ocotp *otp = context; | |
73 | unsigned int offset = *(u32 *)reg; | |
74 | u32 *buf = val; | |
75 | int ret; | |
76 | ||
77 | ret = clk_enable(otp->clk); | |
78 | if (ret) | |
79 | return ret; | |
80 | ||
81 | writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR); | |
82 | ||
83 | ret = mxs_ocotp_wait(otp); | |
84 | if (ret) | |
85 | goto disable_clk; | |
86 | ||
87 | /* open OCOTP banks for read */ | |
88 | writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET); | |
89 | ||
90 | /* approximately wait 33 hclk cycles */ | |
91 | udelay(1); | |
92 | ||
93 | ret = mxs_ocotp_wait(otp); | |
94 | if (ret) | |
95 | goto close_banks; | |
96 | ||
d1306eb6 | 97 | while (val_size >= reg_size) { |
c01e9a11 SW |
98 | if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) { |
99 | /* fill up non-data register */ | |
100 | *buf = 0; | |
101 | } else { | |
102 | *buf = readl(otp->base + offset); | |
103 | } | |
104 | ||
105 | buf++; | |
d1306eb6 | 106 | val_size -= reg_size; |
c01e9a11 SW |
107 | offset += reg_size; |
108 | } | |
109 | ||
110 | close_banks: | |
111 | /* close banks for power saving */ | |
112 | writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR); | |
113 | ||
114 | disable_clk: | |
115 | clk_disable(otp->clk); | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
120 | static int mxs_ocotp_write(void *context, const void *data, size_t count) | |
121 | { | |
122 | /* We don't want to support writing */ | |
123 | return 0; | |
124 | } | |
125 | ||
126 | static bool mxs_ocotp_writeable_reg(struct device *dev, unsigned int reg) | |
127 | { | |
128 | return false; | |
129 | } | |
130 | ||
131 | static struct nvmem_config ocotp_config = { | |
132 | .name = "mxs-ocotp", | |
133 | .owner = THIS_MODULE, | |
134 | }; | |
135 | ||
136 | static const struct regmap_range imx23_ranges[] = { | |
137 | regmap_reg_range(OCOTP_DATA_OFFSET, 0x210), | |
138 | }; | |
139 | ||
140 | static const struct regmap_access_table imx23_access = { | |
141 | .yes_ranges = imx23_ranges, | |
142 | .n_yes_ranges = ARRAY_SIZE(imx23_ranges), | |
143 | }; | |
144 | ||
145 | static const struct regmap_range imx28_ranges[] = { | |
146 | regmap_reg_range(OCOTP_DATA_OFFSET, 0x290), | |
147 | }; | |
148 | ||
149 | static const struct regmap_access_table imx28_access = { | |
150 | .yes_ranges = imx28_ranges, | |
151 | .n_yes_ranges = ARRAY_SIZE(imx28_ranges), | |
152 | }; | |
153 | ||
154 | static struct regmap_bus mxs_ocotp_bus = { | |
155 | .read = mxs_ocotp_read, | |
156 | .write = mxs_ocotp_write, /* make regmap_init() happy */ | |
157 | .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, | |
158 | .val_format_endian_default = REGMAP_ENDIAN_NATIVE, | |
159 | }; | |
160 | ||
161 | static struct regmap_config mxs_ocotp_config = { | |
162 | .reg_bits = 32, | |
163 | .val_bits = 32, | |
164 | .reg_stride = 16, | |
165 | .writeable_reg = mxs_ocotp_writeable_reg, | |
166 | }; | |
167 | ||
168 | static const struct of_device_id mxs_ocotp_match[] = { | |
169 | { .compatible = "fsl,imx23-ocotp", .data = &imx23_access }, | |
170 | { .compatible = "fsl,imx28-ocotp", .data = &imx28_access }, | |
171 | { /* sentinel */}, | |
172 | }; | |
173 | MODULE_DEVICE_TABLE(of, mxs_ocotp_match); | |
174 | ||
175 | static int mxs_ocotp_probe(struct platform_device *pdev) | |
176 | { | |
177 | struct device *dev = &pdev->dev; | |
178 | struct mxs_ocotp *otp; | |
179 | struct resource *res; | |
180 | const struct of_device_id *match; | |
181 | struct regmap *regmap; | |
182 | const struct regmap_access_table *access; | |
183 | int ret; | |
184 | ||
185 | match = of_match_device(dev->driver->of_match_table, dev); | |
186 | if (!match || !match->data) | |
187 | return -EINVAL; | |
188 | ||
189 | otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL); | |
190 | if (!otp) | |
191 | return -ENOMEM; | |
192 | ||
193 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
194 | otp->base = devm_ioremap_resource(dev, res); | |
195 | if (IS_ERR(otp->base)) | |
196 | return PTR_ERR(otp->base); | |
197 | ||
198 | otp->clk = devm_clk_get(&pdev->dev, NULL); | |
199 | if (IS_ERR(otp->clk)) | |
200 | return PTR_ERR(otp->clk); | |
201 | ||
202 | ret = clk_prepare(otp->clk); | |
203 | if (ret < 0) { | |
204 | dev_err(dev, "failed to prepare clk: %d\n", ret); | |
205 | return ret; | |
206 | } | |
207 | ||
208 | access = match->data; | |
209 | mxs_ocotp_config.rd_table = access; | |
210 | mxs_ocotp_config.max_register = access->yes_ranges[0].range_max; | |
211 | ||
212 | regmap = devm_regmap_init(dev, &mxs_ocotp_bus, otp, &mxs_ocotp_config); | |
213 | if (IS_ERR(regmap)) { | |
214 | dev_err(dev, "regmap init failed\n"); | |
215 | ret = PTR_ERR(regmap); | |
216 | goto err_clk; | |
217 | } | |
218 | ||
219 | ocotp_config.dev = dev; | |
220 | otp->nvmem = nvmem_register(&ocotp_config); | |
221 | if (IS_ERR(otp->nvmem)) { | |
222 | ret = PTR_ERR(otp->nvmem); | |
223 | goto err_clk; | |
224 | } | |
225 | ||
226 | platform_set_drvdata(pdev, otp); | |
227 | ||
228 | return 0; | |
229 | ||
230 | err_clk: | |
231 | clk_unprepare(otp->clk); | |
232 | ||
233 | return ret; | |
234 | } | |
235 | ||
236 | static int mxs_ocotp_remove(struct platform_device *pdev) | |
237 | { | |
238 | struct mxs_ocotp *otp = platform_get_drvdata(pdev); | |
239 | ||
240 | clk_unprepare(otp->clk); | |
241 | ||
242 | return nvmem_unregister(otp->nvmem); | |
243 | } | |
244 | ||
245 | static struct platform_driver mxs_ocotp_driver = { | |
246 | .probe = mxs_ocotp_probe, | |
247 | .remove = mxs_ocotp_remove, | |
248 | .driver = { | |
249 | .name = "mxs-ocotp", | |
250 | .of_match_table = mxs_ocotp_match, | |
251 | }, | |
252 | }; | |
253 | ||
254 | module_platform_driver(mxs_ocotp_driver); | |
255 | MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); | |
256 | MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28"); | |
257 | MODULE_LICENSE("GPL v2"); |