drivers/nvmem/airoha-smc-efuses.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  Author: Christian Marangi <ansuelsmth@gmail.com>
 */

#include <linux/arm-smccc.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/regmap.h>

#define AIROHA_SMC_EFUSE_FID		0x82000001
#define AIROHA_SMC_EFUSE_SUB_ID_READ	0x44414552

#define AIROHA_EFUSE_CELLS		64

struct airoha_efuse_bank_priv {
	u32 bank_index;
};

static int airoha_efuse_read(void *context, unsigned int offset,
			     void *val, size_t bytes)
{
	struct regmap *regmap = context;

	return regmap_bulk_read(regmap, offset,
				val, bytes / sizeof(u32));
}

static int airoha_efuse_reg_read(void *context, unsigned int offset,
				 unsigned int *val)
{
	struct airoha_efuse_bank_priv *priv = context;
	struct arm_smccc_res res;

	arm_smccc_1_1_invoke(AIROHA_SMC_EFUSE_FID,
			     AIROHA_SMC_EFUSE_SUB_ID_READ,
			     priv->bank_index, offset, 0, 0, 0, 0, &res);

	/* check if SMC reported an error */
	if (res.a0)
		return -EIO;

	*val = res.a1;
	return 0;
}

static int airoha_efuse_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	int ret;

	for_each_child_of_node_scoped(dev->of_node, child) {
		struct nvmem_config nvmem_config = {
			.size = AIROHA_EFUSE_CELLS * sizeof(u32),
			.stride = sizeof(u32),
			.word_size = sizeof(u32),
			.reg_read = airoha_efuse_read,
		};
		struct regmap_config regmap_config = {
			.reg_read = airoha_efuse_reg_read,
			.reg_bits = 32,
			.val_bits = 32,
			.reg_stride = 4,
		};
		struct airoha_efuse_bank_priv *priv;
		struct nvmem_device *nvmem;
		struct regmap *regmap;
		const char *name;
		u32 bank;

		ret = of_property_read_u32(child, "reg", &bank);
		if (ret)
			return ret;

		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
		if (!priv)
			return -ENOMEM;

		name = devm_kasprintf(dev, GFP_KERNEL, "airoha-efuse-%u",
				      bank);
		if (!name)
			return -ENOMEM;

		priv->bank_index = bank;

		regmap_config.name = name;
		regmap = devm_regmap_init(dev, NULL, priv,
					  &regmap_config);
		if (IS_ERR(regmap))
			return PTR_ERR(regmap);

		nvmem_config.name = name;
		nvmem_config.priv = regmap;
		nvmem_config.dev = dev;
		nvmem_config.id = bank;
		nvmem_config.of_node = child;
		nvmem = devm_nvmem_register(dev, &nvmem_config);
		if (IS_ERR(nvmem))
			return PTR_ERR(nvmem);
	}

	return 0;
}

static const struct of_device_id airoha_efuse_of_match[] = {
	{ .compatible = "airoha,an7581-efuses", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, airoha_efuse_of_match);

static struct platform_driver airoha_efuse_driver = {
	.probe = airoha_efuse_probe,
	.driver = {
		.name = "airoha-efuse",
		.of_match_table = airoha_efuse_of_match,
	},
};
module_platform_driver(airoha_efuse_driver);

MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
MODULE_DESCRIPTION("Driver for Airoha SMC eFUSEs");
MODULE_LICENSE("GPL");