1/*
2 * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
3 * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2
7 * as published by the Free Software Foundation.
8 */
9
10#include <linux/mfd/syscon.h>
11#include <linux/module.h>
12#include <linux/nvmem-provider.h>
13#include <linux/of_device.h>
14#include <linux/regmap.h>
15
16#define IMX6Q_SNVS_HPLR 0x00
17#define IMX6Q_SNVS_LPLR 0x34
18#define IMX6Q_SNVS_LPGPR 0x68
19
20#define IMX7D_SNVS_HPLR 0x00
21#define IMX7D_SNVS_LPLR 0x34
22#define IMX7D_SNVS_LPGPR 0x90
23
24#define IMX_GPR_SL BIT(5)
25#define IMX_GPR_HL BIT(5)
26
27struct snvs_lpgpr_cfg {
28 int offset;
29 int offset_hplr;
30 int offset_lplr;
31 int size;
32};
33
34struct snvs_lpgpr_priv {
35 struct device_d *dev;
36 struct regmap *regmap;
37 struct nvmem_config cfg;
38 const struct snvs_lpgpr_cfg *dcfg;
39};
40
41static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
42 .offset = IMX6Q_SNVS_LPGPR,
43 .offset_hplr = IMX6Q_SNVS_HPLR,
44 .offset_lplr = IMX6Q_SNVS_LPLR,
45 .size = 4,
46};
47
48static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
49 .offset = IMX7D_SNVS_LPGPR,
50 .offset_hplr = IMX7D_SNVS_HPLR,
51 .offset_lplr = IMX7D_SNVS_LPLR,
52 .size = 16,
53};
54
55static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
56 size_t bytes)
57{
58 struct snvs_lpgpr_priv *priv = context;
59 const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
60 unsigned int lock_reg;
61 int ret;
62
63 ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
64 if (ret < 0)
65 return ret;
66
67 if (lock_reg & IMX_GPR_SL)
68 return -EPERM;
69
70 ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
71 if (ret < 0)
72 return ret;
73
74 if (lock_reg & IMX_GPR_HL)
75 return -EPERM;
76
77 return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
78 bytes / 4);
79}
80
81static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
82 size_t bytes)
83{
84 struct snvs_lpgpr_priv *priv = context;
85 const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
86
87 return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
88 val, bytes / 4);
89}
90
91static int snvs_lpgpr_probe(struct platform_device *pdev)
92{
93 struct device *dev = &pdev->dev;
94 struct device_node *node = dev->of_node;
95 struct device_node *syscon_node;
96 struct snvs_lpgpr_priv *priv;
97 struct nvmem_config *cfg;
98 struct nvmem_device *nvmem;
99 const struct snvs_lpgpr_cfg *dcfg;
100
101 if (!node)
102 return -ENOENT;
103
104 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
105 if (!priv)
106 return -ENOMEM;
107
108 dcfg = of_device_get_match_data(dev);
109 if (!dcfg)
110 return -EINVAL;
111
112 syscon_node = of_get_parent(node);
113 if (!syscon_node)
114 return -ENODEV;
115
116 priv->regmap = syscon_node_to_regmap(syscon_node);
117 of_node_put(syscon_node);
118 if (IS_ERR(priv->regmap))
119 return PTR_ERR(priv->regmap);
120
121 priv->dcfg = dcfg;
122
123 cfg = &priv->cfg;
124 cfg->priv = priv;
125 cfg->name = dev_name(dev);
126 cfg->dev = dev;
127 cfg->stride = 4;
128 cfg->word_size = 4;
129 cfg->size = dcfg->size,
130 cfg->owner = THIS_MODULE;
131 cfg->reg_read = snvs_lpgpr_read;
132 cfg->reg_write = snvs_lpgpr_write;
133
134 nvmem = devm_nvmem_register(dev, cfg);
135
136 return PTR_ERR_OR_ZERO(nvmem);
137}
138
139static const struct of_device_id snvs_lpgpr_dt_ids[] = {
140 { .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
141 { .compatible = "fsl,imx6ul-snvs-lpgpr",
142 .data = &snvs_lpgpr_cfg_imx6q },
143 { .compatible = "fsl,imx7d-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx7d },
144 { },
145};
146MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
147
148static struct platform_driver snvs_lpgpr_driver = {
149 .probe = snvs_lpgpr_probe,
150 .driver = {
151 .name = "snvs_lpgpr",
152 .of_match_table = snvs_lpgpr_dt_ids,
153 },
154};
155module_platform_driver(snvs_lpgpr_driver);
156
157MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
158MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 and i.MX7 Secure Non-Volatile Storage");
159MODULE_LICENSE("GPL v2");
160