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// SPDX-License-Identifier: GPL-2.0-only
/*
* sfr.c - driver for special function registers
*
* Copyright (C) 2019 Bootlin.
*
*/
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/random.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#define SFR_SN0 0x4c
#define SFR_SN_SIZE 8
struct atmel_sfr_priv {
struct regmap *regmap;
};
static int atmel_sfr_read(void *context, unsigned int offset,
void *buf, size_t bytes)
{
struct atmel_sfr_priv *priv = context;
return regmap_bulk_read(priv->regmap, SFR_SN0 + offset,
buf, bytes / 4);
}
static struct nvmem_config atmel_sfr_nvmem_config = {
.name = "atmel-sfr",
.read_only = true,
.word_size = 4,
.stride = 4,
.size = SFR_SN_SIZE,
.reg_read = atmel_sfr_read,
};
static int atmel_sfr_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct nvmem_device *nvmem;
struct atmel_sfr_priv *priv;
u8 sn[SFR_SN_SIZE];
int ret;
priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->regmap = syscon_node_to_regmap(np);
if (IS_ERR(priv->regmap)) {
dev_err(dev, "cannot get parent's regmap\n");
return PTR_ERR(priv->regmap);
}
atmel_sfr_nvmem_config.dev = dev;
atmel_sfr_nvmem_config.priv = priv;
nvmem = devm_nvmem_register(dev, &atmel_sfr_nvmem_config);
if (IS_ERR(nvmem)) {
dev_err(dev, "error registering nvmem config\n");
return PTR_ERR(nvmem);
}
ret = atmel_sfr_read(priv, 0, sn, SFR_SN_SIZE);
if (ret == 0)
add_device_randomness(sn, SFR_SN_SIZE);
return ret;
}
static const struct of_device_id atmel_sfr_dt_ids[] = {
{
.compatible = "atmel,sama5d2-sfr",
}, {
.compatible = "atmel,sama5d4-sfr",
}, {
/* sentinel */
},
};
MODULE_DEVICE_TABLE(of, atmel_sfr_dt_ids);
static struct platform_driver atmel_sfr_driver = {
.probe = atmel_sfr_probe,
.driver = {
.name = "atmel-sfr",
.of_match_table = atmel_sfr_dt_ids,
},
};
module_platform_driver(atmel_sfr_driver);
MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
MODULE_DESCRIPTION("Atmel SFR SN driver for SAMA5D2/4 SoC family");
MODULE_LICENSE("GPL v2");
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