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