1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Amlogic Meson GX eFuse Driver
  4 *
  5 * Copyright (c) 2016 Endless Computers, Inc.
  6 * Author: Carlo Caione <carlo@endlessm.com>
  7 */
  8
  9#include <linux/clk.h>
 10#include <linux/module.h>
 11#include <linux/nvmem-provider.h>
 12#include <linux/of.h>
 13#include <linux/platform_device.h>
 14
 15#include <linux/firmware/meson/meson_sm.h>
 16
 17static int meson_efuse_read(void *context, unsigned int offset,
 18			    void *val, size_t bytes)
 19{
 20	struct meson_sm_firmware *fw = context;
 21
 22	return meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
 23				  bytes, 0, 0, 0);
 24}
 25
 26static int meson_efuse_write(void *context, unsigned int offset,
 27			     void *val, size_t bytes)
 28{
 29	struct meson_sm_firmware *fw = context;
 30
 31	return meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
 32				   bytes, 0, 0, 0);
 33}
 34
 35static const struct of_device_id meson_efuse_match[] = {
 36	{ .compatible = "amlogic,meson-gxbb-efuse", },
 37	{ /* sentinel */ },
 38};
 39MODULE_DEVICE_TABLE(of, meson_efuse_match);
 40
 41static int meson_efuse_probe(struct platform_device *pdev)
 42{
 43	struct device *dev = &pdev->dev;
 44	struct meson_sm_firmware *fw;
 45	struct device_node *sm_np;
 46	struct nvmem_device *nvmem;
 47	struct nvmem_config *econfig;
 48	struct clk *clk;
 49	unsigned int size;
 50
 51	sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
 52	if (!sm_np) {
 53		dev_err(&pdev->dev, "no secure-monitor node\n");
 54		return -ENODEV;
 55	}
 56
 57	fw = meson_sm_get(sm_np);
 58	of_node_put(sm_np);
 59	if (!fw)
 60		return -EPROBE_DEFER;
 61
 62	clk = devm_clk_get_enabled(dev, NULL);
 63	if (IS_ERR(clk))
 64		return dev_err_probe(dev, PTR_ERR(clk), "failed to get efuse gate");
 65
 66	if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
 67		dev_err(dev, "failed to get max user");
 68		return -EINVAL;
 69	}
 70
 71	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
 72	if (!econfig)
 73		return -ENOMEM;
 74
 75	econfig->dev = dev;
 76	econfig->name = dev_name(dev);
 77	econfig->add_legacy_fixed_of_cells = true;
 78	econfig->stride = 1;
 79	econfig->word_size = 1;
 80	econfig->reg_read = meson_efuse_read;
 81	econfig->reg_write = meson_efuse_write;
 82	econfig->size = size;
 83	econfig->priv = fw;
 84
 85	nvmem = devm_nvmem_register(&pdev->dev, econfig);
 86
 87	return PTR_ERR_OR_ZERO(nvmem);
 88}
 89
 90static struct platform_driver meson_efuse_driver = {
 91	.probe = meson_efuse_probe,
 92	.driver = {
 93		.name = "meson-efuse",
 94		.of_match_table = meson_efuse_match,
 95	},
 96};
 97
 98module_platform_driver(meson_efuse_driver);
 99
100MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
101MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
102MODULE_LICENSE("GPL v2");