projects / mirror_ubuntu-hirsute-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| c3277f8e KB |
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"); |