Linux 4.18.10
[linux/fpc-iii.git] / drivers / nvmem / mxs-ocotp.c
blob7018e2ef57147179b75deca13a3e0663158fcec1
1 /*
2 * Freescale MXS On-Chip OTP driver
4 * Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com>
6 * Based on the driver from Huang Shijie and Christoph G. Baumann
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.
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.
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/slab.h>
29 #include <linux/stmp_device.h>
31 /* OCOTP registers and bits */
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)
37 #define OCOTP_TIMEOUT 10000
38 #define OCOTP_DATA_OFFSET 0x20
40 struct mxs_ocotp {
41 struct clk *clk;
42 void __iomem *base;
43 struct nvmem_device *nvmem;
46 static int mxs_ocotp_wait(struct mxs_ocotp *otp)
48 int timeout = OCOTP_TIMEOUT;
49 unsigned int status = 0;
51 while (timeout--) {
52 status = readl(otp->base);
54 if (!(status & (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)))
55 break;
57 cpu_relax();
60 if (status & BM_OCOTP_CTRL_BUSY)
61 return -EBUSY;
62 else if (status & BM_OCOTP_CTRL_ERROR)
63 return -EIO;
65 return 0;
68 static int mxs_ocotp_read(void *context, unsigned int offset,
69 void *val, size_t bytes)
71 struct mxs_ocotp *otp = context;
72 u32 *buf = val;
73 int ret;
75 ret = clk_enable(otp->clk);
76 if (ret)
77 return ret;
79 writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR);
81 ret = mxs_ocotp_wait(otp);
82 if (ret)
83 goto disable_clk;
85 /* open OCOTP banks for read */
86 writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET);
88 /* approximately wait 33 hclk cycles */
89 udelay(1);
91 ret = mxs_ocotp_wait(otp);
92 if (ret)
93 goto close_banks;
95 while (bytes) {
96 if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) {
97 /* fill up non-data register */
98 *buf++ = 0;
99 } else {
100 *buf++ = readl(otp->base + offset);
103 bytes -= 4;
104 offset += 4;
107 close_banks:
108 /* close banks for power saving */
109 writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR);
111 disable_clk:
112 clk_disable(otp->clk);
114 return ret;
117 static struct nvmem_config ocotp_config = {
118 .name = "mxs-ocotp",
119 .stride = 16,
120 .word_size = 4,
121 .reg_read = mxs_ocotp_read,
124 struct mxs_data {
125 int size;
128 static const struct mxs_data imx23_data = {
129 .size = 0x220,
132 static const struct mxs_data imx28_data = {
133 .size = 0x2a0,
136 static const struct of_device_id mxs_ocotp_match[] = {
137 { .compatible = "fsl,imx23-ocotp", .data = &imx23_data },
138 { .compatible = "fsl,imx28-ocotp", .data = &imx28_data },
139 { /* sentinel */},
141 MODULE_DEVICE_TABLE(of, mxs_ocotp_match);
143 static int mxs_ocotp_probe(struct platform_device *pdev)
145 struct device *dev = &pdev->dev;
146 const struct mxs_data *data;
147 struct mxs_ocotp *otp;
148 struct resource *res;
149 const struct of_device_id *match;
150 int ret;
152 match = of_match_device(dev->driver->of_match_table, dev);
153 if (!match || !match->data)
154 return -EINVAL;
156 otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL);
157 if (!otp)
158 return -ENOMEM;
160 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
161 otp->base = devm_ioremap_resource(dev, res);
162 if (IS_ERR(otp->base))
163 return PTR_ERR(otp->base);
165 otp->clk = devm_clk_get(&pdev->dev, NULL);
166 if (IS_ERR(otp->clk))
167 return PTR_ERR(otp->clk);
169 ret = clk_prepare(otp->clk);
170 if (ret < 0) {
171 dev_err(dev, "failed to prepare clk: %d\n", ret);
172 return ret;
175 data = match->data;
177 ocotp_config.size = data->size;
178 ocotp_config.priv = otp;
179 ocotp_config.dev = dev;
180 otp->nvmem = nvmem_register(&ocotp_config);
181 if (IS_ERR(otp->nvmem)) {
182 ret = PTR_ERR(otp->nvmem);
183 goto err_clk;
186 platform_set_drvdata(pdev, otp);
188 return 0;
190 err_clk:
191 clk_unprepare(otp->clk);
193 return ret;
196 static int mxs_ocotp_remove(struct platform_device *pdev)
198 struct mxs_ocotp *otp = platform_get_drvdata(pdev);
200 clk_unprepare(otp->clk);
202 return nvmem_unregister(otp->nvmem);
205 static struct platform_driver mxs_ocotp_driver = {
206 .probe = mxs_ocotp_probe,
207 .remove = mxs_ocotp_remove,
208 .driver = {
209 .name = "mxs-ocotp",
210 .of_match_table = mxs_ocotp_match,
214 module_platform_driver(mxs_ocotp_driver);
215 MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
216 MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
217 MODULE_LICENSE("GPL v2");