| Olivier Deprez | 157378f | 2022-04-04 15:47:50 +0200 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * sfr.c - driver for special function registers |
| 4 | * |
| 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/of_device.h> |
| 14 | #include <linux/platform_device.h> |
| 15 | #include <linux/regmap.h> |
| 16 | |
| 17 | #define SFR_SN0 0x4c |
| 18 | #define SFR_SN_SIZE 8 |
| 19 | |
| 20 | struct atmel_sfr_priv { |
| 21 | struct regmap *regmap; |
| 22 | }; |
| 23 | |
| 24 | static int atmel_sfr_read(void *context, unsigned int offset, |
| 25 | void *buf, size_t bytes) |
| 26 | { |
| 27 | struct atmel_sfr_priv *priv = context; |
| 28 | |
| 29 | return regmap_bulk_read(priv->regmap, SFR_SN0 + offset, |
| 30 | buf, bytes / 4); |
| 31 | } |
| 32 | |
| 33 | static struct nvmem_config atmel_sfr_nvmem_config = { |
| 34 | .name = "atmel-sfr", |
| 35 | .read_only = true, |
| 36 | .word_size = 4, |
| 37 | .stride = 4, |
| 38 | .size = SFR_SN_SIZE, |
| 39 | .reg_read = atmel_sfr_read, |
| 40 | }; |
| 41 | |
| 42 | static int atmel_sfr_probe(struct platform_device *pdev) |
| 43 | { |
| 44 | struct device *dev = &pdev->dev; |
| 45 | struct device_node *np = dev->of_node; |
| 46 | struct nvmem_device *nvmem; |
| 47 | struct atmel_sfr_priv *priv; |
| 48 | u8 sn[SFR_SN_SIZE]; |
| 49 | int ret; |
| 50 | |
| 51 | priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL); |
| 52 | if (!priv) |
| 53 | return -ENOMEM; |
| 54 | |
| 55 | priv->regmap = syscon_node_to_regmap(np); |
| 56 | if (IS_ERR(priv->regmap)) { |
| 57 | dev_err(dev, "cannot get parent's regmap\n"); |
| 58 | return PTR_ERR(priv->regmap); |
| 59 | } |
| 60 | |
| 61 | atmel_sfr_nvmem_config.dev = dev; |
| 62 | atmel_sfr_nvmem_config.priv = priv; |
| 63 | |
| 64 | nvmem = devm_nvmem_register(dev, &atmel_sfr_nvmem_config); |
| 65 | if (IS_ERR(nvmem)) { |
| 66 | dev_err(dev, "error registering nvmem config\n"); |
| 67 | return PTR_ERR(nvmem); |
| 68 | } |
| 69 | |
| 70 | ret = atmel_sfr_read(priv, 0, sn, SFR_SN_SIZE); |
| 71 | if (ret == 0) |
| 72 | add_device_randomness(sn, SFR_SN_SIZE); |
| 73 | |
| 74 | return ret; |
| 75 | } |
| 76 | |
| 77 | static const struct of_device_id atmel_sfr_dt_ids[] = { |
| 78 | { |
| 79 | .compatible = "atmel,sama5d2-sfr", |
| 80 | }, { |
| 81 | .compatible = "atmel,sama5d4-sfr", |
| 82 | }, { |
| 83 | /* sentinel */ |
| 84 | }, |
| 85 | }; |
| 86 | MODULE_DEVICE_TABLE(of, atmel_sfr_dt_ids); |
| 87 | |
| 88 | static struct platform_driver atmel_sfr_driver = { |
| 89 | .probe = atmel_sfr_probe, |
| 90 | .driver = { |
| 91 | .name = "atmel-sfr", |
| 92 | .of_match_table = atmel_sfr_dt_ids, |
| 93 | }, |
| 94 | }; |
| 95 | module_platform_driver(atmel_sfr_driver); |
| 96 | |
| 97 | MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>"); |
| 98 | MODULE_DESCRIPTION("Atmel SFR SN driver for SAMA5D2/4 SoC family"); |
| 99 | MODULE_LICENSE("GPL v2"); |