1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
3 * Amlogic Meson Reset Controller driver
5 * Copyright (c) 2016 BayLibre, SAS.
9 #include <linux/init.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset-controller.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 #include <linux/of_device.h>
19 #define BITS_PER_REG 32
20 #define LEVEL_OFFSET 0x7c
23 void __iomem *reg_base;
24 struct reset_controller_dev rcdev;
28 static int meson_reset_reset(struct reset_controller_dev *rcdev,
31 struct meson_reset *data =
32 container_of(rcdev, struct meson_reset, rcdev);
33 unsigned int bank = id / BITS_PER_REG;
34 unsigned int offset = id % BITS_PER_REG;
35 void __iomem *reg_addr = data->reg_base + (bank << 2);
37 writel(BIT(offset), reg_addr);
42 static int meson_reset_level(struct reset_controller_dev *rcdev,
43 unsigned long id, bool assert)
45 struct meson_reset *data =
46 container_of(rcdev, struct meson_reset, rcdev);
47 unsigned int bank = id / BITS_PER_REG;
48 unsigned int offset = id % BITS_PER_REG;
49 void __iomem *reg_addr = data->reg_base + LEVEL_OFFSET + (bank << 2);
53 spin_lock_irqsave(&data->lock, flags);
55 reg = readl(reg_addr);
57 writel(reg & ~BIT(offset), reg_addr);
59 writel(reg | BIT(offset), reg_addr);
61 spin_unlock_irqrestore(&data->lock, flags);
66 static int meson_reset_assert(struct reset_controller_dev *rcdev,
69 return meson_reset_level(rcdev, id, true);
72 static int meson_reset_deassert(struct reset_controller_dev *rcdev,
75 return meson_reset_level(rcdev, id, false);
78 static const struct reset_control_ops meson_reset_ops = {
79 .reset = meson_reset_reset,
80 .assert = meson_reset_assert,
81 .deassert = meson_reset_deassert,
84 static const struct of_device_id meson_reset_dt_ids[] = {
85 { .compatible = "amlogic,meson8b-reset" },
86 { .compatible = "amlogic,meson-gxbb-reset" },
87 { .compatible = "amlogic,meson-axg-reset" },
91 static int meson_reset_probe(struct platform_device *pdev)
93 struct meson_reset *data;
96 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
100 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
101 data->reg_base = devm_ioremap_resource(&pdev->dev, res);
102 if (IS_ERR(data->reg_base))
103 return PTR_ERR(data->reg_base);
105 platform_set_drvdata(pdev, data);
107 spin_lock_init(&data->lock);
109 data->rcdev.owner = THIS_MODULE;
110 data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
111 data->rcdev.ops = &meson_reset_ops;
112 data->rcdev.of_node = pdev->dev.of_node;
114 return devm_reset_controller_register(&pdev->dev, &data->rcdev);
117 static struct platform_driver meson_reset_driver = {
118 .probe = meson_reset_probe,
120 .name = "meson_reset",
121 .of_match_table = meson_reset_dt_ids,
124 builtin_platform_driver(meson_reset_driver);