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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * sfr.c - driver for special function registers4 *5 * Copyright (C) 2019 Bootlin.6 *7 */8#include <linux/mfd/syscon.h>9#include <linux/module.h>10#include <linux/nvmem-provider.h>11#include <linux/random.h>12#include <linux/of.h>13#include <linux/platform_device.h>14#include <linux/regmap.h>15 16#define SFR_SN0 0x4c17#define SFR_SN_SIZE 818 19struct atmel_sfr_priv {20 struct regmap *regmap;21};22 23static int atmel_sfr_read(void *context, unsigned int offset,24 void *buf, size_t bytes)25{26 struct atmel_sfr_priv *priv = context;27 28 return regmap_bulk_read(priv->regmap, SFR_SN0 + offset,29 buf, bytes / 4);30}31 32static struct nvmem_config atmel_sfr_nvmem_config = {33 .name = "atmel-sfr",34 .read_only = true,35 .word_size = 4,36 .stride = 4,37 .size = SFR_SN_SIZE,38 .reg_read = atmel_sfr_read,39};40 41static int atmel_sfr_probe(struct platform_device *pdev)42{43 struct device *dev = &pdev->dev;44 struct device_node *np = dev->of_node;45 struct nvmem_device *nvmem;46 struct atmel_sfr_priv *priv;47 u8 sn[SFR_SN_SIZE];48 int ret;49 50 priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL);51 if (!priv)52 return -ENOMEM;53 54 priv->regmap = syscon_node_to_regmap(np);55 if (IS_ERR(priv->regmap)) {56 dev_err(dev, "cannot get parent's regmap\n");57 return PTR_ERR(priv->regmap);58 }59 60 atmel_sfr_nvmem_config.dev = dev;61 atmel_sfr_nvmem_config.priv = priv;62 63 nvmem = devm_nvmem_register(dev, &atmel_sfr_nvmem_config);64 if (IS_ERR(nvmem)) {65 dev_err(dev, "error registering nvmem config\n");66 return PTR_ERR(nvmem);67 }68 69 ret = atmel_sfr_read(priv, 0, sn, SFR_SN_SIZE);70 if (ret == 0)71 add_device_randomness(sn, SFR_SN_SIZE);72 73 return ret;74}75 76static const struct of_device_id atmel_sfr_dt_ids[] = {77 {78 .compatible = "atmel,sama5d2-sfr",79 }, {80 .compatible = "atmel,sama5d4-sfr",81 }, {82 /* sentinel */83 },84};85MODULE_DEVICE_TABLE(of, atmel_sfr_dt_ids);86 87static struct platform_driver atmel_sfr_driver = {88 .probe = atmel_sfr_probe,89 .driver = {90 .name = "atmel-sfr",91 .of_match_table = atmel_sfr_dt_ids,92 },93};94module_platform_driver(atmel_sfr_driver);95 96MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");97MODULE_DESCRIPTION("Atmel SFR SN driver for SAMA5D2/4 SoC family");98MODULE_LICENSE("GPL v2");99