1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
4 * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
5 */
6
7#include <linux/mfd/syscon.h>
8#include <linux/module.h>
9#include <linux/nvmem-provider.h>
10#include <linux/of_device.h>
11#include <linux/regmap.h>
12
13#define IMX6Q_SNVS_HPLR		0x00
14#define IMX6Q_SNVS_LPLR		0x34
15#define IMX6Q_SNVS_LPGPR	0x68
16
17#define IMX7D_SNVS_HPLR		0x00
18#define IMX7D_SNVS_LPLR		0x34
19#define IMX7D_SNVS_LPGPR	0x90
20
21#define IMX_GPR_SL		BIT(5)
22#define IMX_GPR_HL		BIT(5)
23
24struct snvs_lpgpr_cfg {
25	int offset;
26	int offset_hplr;
27	int offset_lplr;
28	int size;
29};
30
31struct snvs_lpgpr_priv {
32	struct device_d			*dev;
33	struct regmap			*regmap;
34	struct nvmem_config		cfg;
35	const struct snvs_lpgpr_cfg	*dcfg;
36};
37
38static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
39	.offset		= IMX6Q_SNVS_LPGPR,
40	.offset_hplr	= IMX6Q_SNVS_HPLR,
41	.offset_lplr	= IMX6Q_SNVS_LPLR,
42	.size		= 4,
43};
44
45static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
46	.offset		= IMX7D_SNVS_LPGPR,
47	.offset_hplr	= IMX7D_SNVS_HPLR,
48	.offset_lplr	= IMX7D_SNVS_LPLR,
49	.size		= 16,
50};
51
52static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
53			    size_t bytes)
54{
55	struct snvs_lpgpr_priv *priv = context;
56	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
57	unsigned int lock_reg;
58	int ret;
59
60	ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
61	if (ret < 0)
62		return ret;
63
64	if (lock_reg & IMX_GPR_SL)
65		return -EPERM;
66
67	ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
68	if (ret < 0)
69		return ret;
70
71	if (lock_reg & IMX_GPR_HL)
72		return -EPERM;
73
74	return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
75				bytes / 4);
76}
77
78static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
79			   size_t bytes)
80{
81	struct snvs_lpgpr_priv *priv = context;
82	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
83
84	return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
85			       val, bytes / 4);
86}
87
88static int snvs_lpgpr_probe(struct platform_device *pdev)
89{
90	struct device *dev = &pdev->dev;
91	struct device_node *node = dev->of_node;
92	struct device_node *syscon_node;
93	struct snvs_lpgpr_priv *priv;
94	struct nvmem_config *cfg;
95	struct nvmem_device *nvmem;
96	const struct snvs_lpgpr_cfg *dcfg;
97
98	if (!node)
99		return -ENOENT;
100
101	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
102	if (!priv)
103		return -ENOMEM;
104
105	dcfg = of_device_get_match_data(dev);
106	if (!dcfg)
107		return -EINVAL;
108
109	syscon_node = of_get_parent(node);
110	if (!syscon_node)
111		return -ENODEV;
112
113	priv->regmap = syscon_node_to_regmap(syscon_node);
114	of_node_put(syscon_node);
115	if (IS_ERR(priv->regmap))
116		return PTR_ERR(priv->regmap);
117
118	priv->dcfg = dcfg;
119
120	cfg = &priv->cfg;
121	cfg->priv = priv;
122	cfg->name = dev_name(dev);
123	cfg->dev = dev;
124	cfg->stride = 4;
125	cfg->word_size = 4;
126	cfg->size = dcfg->size,
127	cfg->owner = THIS_MODULE;
128	cfg->reg_read  = snvs_lpgpr_read;
129	cfg->reg_write = snvs_lpgpr_write;
130
131	nvmem = devm_nvmem_register(dev, cfg);
132
133	return PTR_ERR_OR_ZERO(nvmem);
134}
135
136static const struct of_device_id snvs_lpgpr_dt_ids[] = {
137	{ .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
138	{ .compatible = "fsl,imx6ul-snvs-lpgpr",
139	  .data = &snvs_lpgpr_cfg_imx6q },
140	{ .compatible = "fsl,imx7d-snvs-lpgpr",	.data = &snvs_lpgpr_cfg_imx7d },
141	{ },
142};
143MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
144
145static struct platform_driver snvs_lpgpr_driver = {
146	.probe	= snvs_lpgpr_probe,
147	.driver = {
148		.name	= "snvs_lpgpr",
149		.of_match_table = snvs_lpgpr_dt_ids,
150	},
151};
152module_platform_driver(snvs_lpgpr_driver);
153
154MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
155MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 and i.MX7 Secure Non-Volatile Storage");
156MODULE_LICENSE("GPL v2");
157