1/*
2 * i.MX6 OCOTP fusebox driver
3 *
4 * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
5 *
6 * Based on the barebox ocotp driver,
7 * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
8 *	Orex Computed Radiography
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation.
13 *
14 * http://www.opensource.org/licenses/gpl-license.html
15 * http://www.gnu.org/copyleft/gpl.html
16 */
17
18#include <linux/device.h>
19#include <linux/io.h>
20#include <linux/module.h>
21#include <linux/nvmem-provider.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/platform_device.h>
25#include <linux/regmap.h>
26#include <linux/slab.h>
27
28struct ocotp_priv {
29	struct device *dev;
30	void __iomem *base;
31	unsigned int nregs;
32};
33
34static int imx_ocotp_read(void *context, const void *reg, size_t reg_size,
35			  void *val, size_t val_size)
36{
37	struct ocotp_priv *priv = context;
38	unsigned int offset = *(u32 *)reg;
39	unsigned int count;
40	int i;
41	u32 index;
42
43	index = offset >> 2;
44	count = val_size >> 2;
45
46	if (count > (priv->nregs - index))
47		count = priv->nregs - index;
48
49	for (i = index; i < (index + count); i++) {
50		*(u32 *)val = readl(priv->base + 0x400 + i * 0x10);
51		val += 4;
52	}
53
54	return (i - index) * 4;
55}
56
57static int imx_ocotp_write(void *context, const void *data, size_t count)
58{
59	/* Not implemented */
60	return 0;
61}
62
63static struct regmap_bus imx_ocotp_bus = {
64	.read = imx_ocotp_read,
65	.write = imx_ocotp_write,
66	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
67	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
68};
69
70static bool imx_ocotp_writeable_reg(struct device *dev, unsigned int reg)
71{
72	return false;
73}
74
75static struct regmap_config imx_ocotp_regmap_config = {
76	.reg_bits = 32,
77	.val_bits = 32,
78	.reg_stride = 4,
79	.writeable_reg = imx_ocotp_writeable_reg,
80	.name = "imx-ocotp",
81};
82
83static struct nvmem_config imx_ocotp_nvmem_config = {
84	.name = "imx-ocotp",
85	.read_only = true,
86	.owner = THIS_MODULE,
87};
88
89static const struct of_device_id imx_ocotp_dt_ids[] = {
90	{ .compatible = "fsl,imx6q-ocotp",  (void *)128 },
91	{ .compatible = "fsl,imx6sl-ocotp", (void *)32 },
92	{ .compatible = "fsl,imx6sx-ocotp", (void *)128 },
93	{ },
94};
95MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
96
97static int imx_ocotp_probe(struct platform_device *pdev)
98{
99	const struct of_device_id *of_id;
100	struct device *dev = &pdev->dev;
101	struct resource *res;
102	struct regmap *regmap;
103	struct ocotp_priv *priv;
104	struct nvmem_device *nvmem;
105
106	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
107	if (!priv)
108		return -ENOMEM;
109
110	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
111	priv->base = devm_ioremap_resource(dev, res);
112	if (IS_ERR(priv->base))
113		return PTR_ERR(priv->base);
114
115	of_id = of_match_device(imx_ocotp_dt_ids, dev);
116	priv->nregs = (unsigned int)of_id->data;
117	imx_ocotp_regmap_config.max_register = 4 * priv->nregs - 4;
118
119	regmap = devm_regmap_init(dev, &imx_ocotp_bus, priv,
120				  &imx_ocotp_regmap_config);
121	if (IS_ERR(regmap)) {
122		dev_err(dev, "regmap init failed\n");
123		return PTR_ERR(regmap);
124	}
125	imx_ocotp_nvmem_config.dev = dev;
126	nvmem = nvmem_register(&imx_ocotp_nvmem_config);
127	if (IS_ERR(nvmem))
128		return PTR_ERR(nvmem);
129
130	platform_set_drvdata(pdev, nvmem);
131
132	return 0;
133}
134
135static int imx_ocotp_remove(struct platform_device *pdev)
136{
137	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
138
139	return nvmem_unregister(nvmem);
140}
141
142static struct platform_driver imx_ocotp_driver = {
143	.probe	= imx_ocotp_probe,
144	.remove	= imx_ocotp_remove,
145	.driver = {
146		.name	= "imx_ocotp",
147		.of_match_table = imx_ocotp_dt_ids,
148	},
149};
150module_platform_driver(imx_ocotp_driver);
151
152MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
153MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
154MODULE_LICENSE("GPL v2");
155