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");