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Stefan Wahrenc01e9a12015-09-30 13:56:27 +01001/*
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>
Stefan Wahrenc01e9a12015-09-30 13:56:27 +010028#include <linux/slab.h>
29#include <linux/stmp_device.h>
30
31/* OCOTP registers and bits */
32
33#define BM_OCOTP_CTRL_RD_BANK_OPEN BIT(12)
34#define BM_OCOTP_CTRL_ERROR BIT(9)
35#define BM_OCOTP_CTRL_BUSY BIT(8)
36
37#define OCOTP_TIMEOUT 10000
38#define OCOTP_DATA_OFFSET 0x20
39
40struct mxs_ocotp {
41 struct clk *clk;
42 void __iomem *base;
43 struct nvmem_device *nvmem;
44};
45
46static int mxs_ocotp_wait(struct mxs_ocotp *otp)
47{
48 int timeout = OCOTP_TIMEOUT;
49 unsigned int status = 0;
50
51 while (timeout--) {
52 status = readl(otp->base);
53
54 if (!(status & (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)))
55 break;
56
57 cpu_relax();
58 }
59
60 if (status & BM_OCOTP_CTRL_BUSY)
61 return -EBUSY;
62 else if (status & BM_OCOTP_CTRL_ERROR)
63 return -EIO;
64
65 return 0;
66}
67
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +010068static int mxs_ocotp_read(void *context, unsigned int offset,
69 void *val, size_t bytes)
Stefan Wahrenc01e9a12015-09-30 13:56:27 +010070{
71 struct mxs_ocotp *otp = context;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +010072 u32 *buf = val;
73 int ret;
74
75 ret = clk_enable(otp->clk);
76 if (ret)
77 return ret;
78
79 writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR);
80
81 ret = mxs_ocotp_wait(otp);
82 if (ret)
83 goto disable_clk;
84
85 /* open OCOTP banks for read */
86 writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET);
87
88 /* approximately wait 33 hclk cycles */
89 udelay(1);
90
91 ret = mxs_ocotp_wait(otp);
92 if (ret)
93 goto close_banks;
94
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +010095 while (bytes) {
Stefan Wahrenc01e9a12015-09-30 13:56:27 +010096 if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) {
97 /* fill up non-data register */
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +010098 *buf++ = 0;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +010099 } else {
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100100 *buf++ = readl(otp->base + offset);
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100101 }
102
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100103 bytes -= 4;
104 offset += 4;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100105 }
106
107close_banks:
108 /* close banks for power saving */
109 writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR);
110
111disable_clk:
112 clk_disable(otp->clk);
113
114 return ret;
115}
116
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100117static struct nvmem_config ocotp_config = {
118 .name = "mxs-ocotp",
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100119 .stride = 16,
120 .word_size = 4,
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100121 .owner = THIS_MODULE,
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100122 .reg_read = mxs_ocotp_read,
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100123};
124
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100125struct mxs_data {
126 int size;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100127};
128
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100129static const struct mxs_data imx23_data = {
130 .size = 0x220,
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100131};
132
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100133static const struct mxs_data imx28_data = {
134 .size = 0x2a0,
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100135};
136
137static const struct of_device_id mxs_ocotp_match[] = {
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100138 { .compatible = "fsl,imx23-ocotp", .data = &imx23_data },
139 { .compatible = "fsl,imx28-ocotp", .data = &imx28_data },
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100140 { /* sentinel */},
141};
142MODULE_DEVICE_TABLE(of, mxs_ocotp_match);
143
144static int mxs_ocotp_probe(struct platform_device *pdev)
145{
146 struct device *dev = &pdev->dev;
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100147 const struct mxs_data *data;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100148 struct mxs_ocotp *otp;
149 struct resource *res;
150 const struct of_device_id *match;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100151 int ret;
152
153 match = of_match_device(dev->driver->of_match_table, dev);
154 if (!match || !match->data)
155 return -EINVAL;
156
157 otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL);
158 if (!otp)
159 return -ENOMEM;
160
161 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
162 otp->base = devm_ioremap_resource(dev, res);
163 if (IS_ERR(otp->base))
164 return PTR_ERR(otp->base);
165
166 otp->clk = devm_clk_get(&pdev->dev, NULL);
167 if (IS_ERR(otp->clk))
168 return PTR_ERR(otp->clk);
169
170 ret = clk_prepare(otp->clk);
171 if (ret < 0) {
172 dev_err(dev, "failed to prepare clk: %d\n", ret);
173 return ret;
174 }
175
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100176 data = match->data;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100177
Srinivas Kandagatla7d8867d2016-05-02 19:36:14 +0100178 ocotp_config.size = data->size;
179 ocotp_config.priv = otp;
Stefan Wahrenc01e9a12015-09-30 13:56:27 +0100180 ocotp_config.dev = dev;
181 otp->nvmem = nvmem_register(&ocotp_config);
182 if (IS_ERR(otp->nvmem)) {
183 ret = PTR_ERR(otp->nvmem);
184 goto err_clk;
185 }
186
187 platform_set_drvdata(pdev, otp);
188
189 return 0;
190
191err_clk:
192 clk_unprepare(otp->clk);
193
194 return ret;
195}
196
197static int mxs_ocotp_remove(struct platform_device *pdev)
198{
199 struct mxs_ocotp *otp = platform_get_drvdata(pdev);
200
201 clk_unprepare(otp->clk);
202
203 return nvmem_unregister(otp->nvmem);
204}
205
206static struct platform_driver mxs_ocotp_driver = {
207 .probe = mxs_ocotp_probe,
208 .remove = mxs_ocotp_remove,
209 .driver = {
210 .name = "mxs-ocotp",
211 .of_match_table = mxs_ocotp_match,
212 },
213};
214
215module_platform_driver(mxs_ocotp_driver);
216MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
217MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
218MODULE_LICENSE("GPL v2");