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/*
* Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
* Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*/
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#define IMX6Q_SNVS_HPLR 0x00
#define IMX6Q_GPR_SL BIT(5)
#define IMX6Q_SNVS_LPLR 0x34
#define IMX6Q_GPR_HL BIT(5)
#define IMX6Q_SNVS_LPGPR 0x68
struct snvs_lpgpr_cfg {
int offset;
int offset_hplr;
int offset_lplr;
};
struct snvs_lpgpr_priv {
struct device_d *dev;
struct regmap *regmap;
struct nvmem_config cfg;
const struct snvs_lpgpr_cfg *dcfg;
};
static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
.offset = IMX6Q_SNVS_LPGPR,
.offset_hplr = IMX6Q_SNVS_HPLR,
.offset_lplr = IMX6Q_SNVS_LPLR,
};
static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
size_t bytes)
{
struct snvs_lpgpr_priv *priv = context;
const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
unsigned int lock_reg;
int ret;
ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
if (ret < 0)
return ret;
if (lock_reg & IMX6Q_GPR_SL)
return -EPERM;
ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
if (ret < 0)
return ret;
if (lock_reg & IMX6Q_GPR_HL)
return -EPERM;
return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
bytes / 4);
}
static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
size_t bytes)
{
struct snvs_lpgpr_priv *priv = context;
const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
val, bytes / 4);
}
static int snvs_lpgpr_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *node = dev->of_node;
struct device_node *syscon_node;
struct snvs_lpgpr_priv *priv;
struct nvmem_config *cfg;
struct nvmem_device *nvmem;
const struct snvs_lpgpr_cfg *dcfg;
if (!node)
return -ENOENT;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
dcfg = of_device_get_match_data(dev);
if (!dcfg)
return -EINVAL;
syscon_node = of_get_parent(node);
if (!syscon_node)
return -ENODEV;
priv->regmap = syscon_node_to_regmap(syscon_node);
of_node_put(syscon_node);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);
priv->dcfg = dcfg;
cfg = &priv->cfg;
cfg->priv = priv;
cfg->name = dev_name(dev);
cfg->dev = dev;
cfg->stride = 4,
cfg->word_size = 4,
cfg->size = 4,
cfg->owner = THIS_MODULE,
cfg->reg_read = snvs_lpgpr_read,
cfg->reg_write = snvs_lpgpr_write,
nvmem = nvmem_register(cfg);
if (IS_ERR(nvmem))
return PTR_ERR(nvmem);
platform_set_drvdata(pdev, nvmem);
return 0;
}
static int snvs_lpgpr_remove(struct platform_device *pdev)
{
struct nvmem_device *nvmem = platform_get_drvdata(pdev);
return nvmem_unregister(nvmem);
}
static const struct of_device_id snvs_lpgpr_dt_ids[] = {
{ .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
{ .compatible = "fsl,imx6ul-snvs-lpgpr",
.data = &snvs_lpgpr_cfg_imx6q },
{ },
};
MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
static struct platform_driver snvs_lpgpr_driver = {
.probe = snvs_lpgpr_probe,
.remove = snvs_lpgpr_remove,
.driver = {
.name = "snvs_lpgpr",
.of_match_table = snvs_lpgpr_dt_ids,
},
};
module_platform_driver(snvs_lpgpr_driver);
MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 Secure Non-Volatile Storage");
MODULE_LICENSE("GPL v2");
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