1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
3 * Copyright (c) 2016 BayLibre, SAS.
4 * Author: Neil Armstrong <narmstrong@baylibre.com>
5 * Copyright (C) 2014 Amlogic, Inc.
8 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/hw_random.h>
12 #include <linux/slab.h>
13 #include <linux/types.h>
15 #include <linux/clk.h>
19 struct meson_rng_data {
21 struct platform_device *pdev;
26 static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
28 struct meson_rng_data *data =
29 container_of(rng, struct meson_rng_data, rng);
31 *(u32 *)buf = readl_relaxed(data->base + RNG_DATA);
36 static void meson_rng_clk_disable(void *data)
38 clk_disable_unprepare(data);
41 static int meson_rng_probe(struct platform_device *pdev)
43 struct device *dev = &pdev->dev;
44 struct meson_rng_data *data;
48 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
54 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
55 data->base = devm_ioremap_resource(dev, res);
56 if (IS_ERR(data->base))
57 return PTR_ERR(data->base);
59 data->core_clk = devm_clk_get(dev, "core");
60 if (IS_ERR(data->core_clk))
61 data->core_clk = NULL;
64 ret = clk_prepare_enable(data->core_clk);
67 ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
73 data->rng.name = pdev->name;
74 data->rng.read = meson_rng_read;
76 platform_set_drvdata(pdev, data);
78 return devm_hwrng_register(dev, &data->rng);
81 static const struct of_device_id meson_rng_of_match[] = {
82 { .compatible = "amlogic,meson-rng", },
85 MODULE_DEVICE_TABLE(of, meson_rng_of_match);
87 static struct platform_driver meson_rng_driver = {
88 .probe = meson_rng_probe,
91 .of_match_table = meson_rng_of_match,
95 module_platform_driver(meson_rng_driver);
97 MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
98 MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
99 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
100 MODULE_LICENSE("Dual BSD/GPL");