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	int ret;
 51
 52	sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
 53	if (!sm_np) {
 54		dev_err(&pdev->dev, "no secure-monitor node\n");
 55		return -ENODEV;
 56	}
 57
 58	fw = meson_sm_get(sm_np);
 59	of_node_put(sm_np);
 60	if (!fw)
 61		return -EPROBE_DEFER;
 62
 63	clk = devm_clk_get(dev, NULL);
 64	if (IS_ERR(clk)) {
 65		ret = PTR_ERR(clk);
 66		if (ret != -EPROBE_DEFER)
 67			dev_err(dev, "failed to get efuse gate");
 68		return ret;
 69	}
 70
 71	ret = clk_prepare_enable(clk);
 72	if (ret) {
 73		dev_err(dev, "failed to enable gate");
 74		return ret;
 75	}
 76
 77	ret = devm_add_action_or_reset(dev,
 78				       (void(*)(void *))clk_disable_unprepare,
 79				       clk);
 80	if (ret) {
 81		dev_err(dev, "failed to add disable callback");
 82		return ret;
 83	}
 84
 85	if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
 86		dev_err(dev, "failed to get max user");
 87		return -EINVAL;
 88	}
 89
 90	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
 91	if (!econfig)
 92		return -ENOMEM;
 93
 94	econfig->dev = dev;
 95	econfig->name = dev_name(dev);
 96	econfig->stride = 1;
 97	econfig->word_size = 1;
 98	econfig->reg_read = meson_efuse_read;
 99	econfig->reg_write = meson_efuse_write;
100	econfig->size = size;
101	econfig->priv = fw;
102
103	nvmem = devm_nvmem_register(&pdev->dev, econfig);
104
105	return PTR_ERR_OR_ZERO(nvmem);
106}
107
108static struct platform_driver meson_efuse_driver = {
109	.probe = meson_efuse_probe,
110	.driver = {
111		.name = "meson-efuse",
112		.of_match_table = meson_efuse_match,
113	},
114};
115
116module_platform_driver(meson_efuse_driver);
117
118MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
119MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
120MODULE_LICENSE("GPL v2");