| // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause |
| /* |
| * Amlogic Meson Reset Controller driver |
| * |
| * Copyright (c) 2016 BayLibre, SAS. |
| * Author: Neil Armstrong <narmstrong@baylibre.com> |
| */ |
| #include <linux/err.h> |
| #include <linux/init.h> |
| #include <linux/io.h> |
| #include <linux/of.h> |
| #include <linux/module.h> |
| #include <linux/platform_device.h> |
| #include <linux/reset-controller.h> |
| #include <linux/slab.h> |
| #include <linux/types.h> |
| |
| #define BITS_PER_REG 32 |
| |
| struct meson_reset_param { |
| int reg_count; |
| int level_offset; |
| }; |
| |
| struct meson_reset { |
| void __iomem *reg_base; |
| const struct meson_reset_param *param; |
| struct reset_controller_dev rcdev; |
| spinlock_t lock; |
| }; |
| |
| static int meson_reset_reset(struct reset_controller_dev *rcdev, |
| unsigned long id) |
| { |
| struct meson_reset *data = |
| container_of(rcdev, struct meson_reset, rcdev); |
| unsigned int bank = id / BITS_PER_REG; |
| unsigned int offset = id % BITS_PER_REG; |
| void __iomem *reg_addr = data->reg_base + (bank << 2); |
| |
| writel(BIT(offset), reg_addr); |
| |
| return 0; |
| } |
| |
| static int meson_reset_level(struct reset_controller_dev *rcdev, |
| unsigned long id, bool assert) |
| { |
| struct meson_reset *data = |
| container_of(rcdev, struct meson_reset, rcdev); |
| unsigned int bank = id / BITS_PER_REG; |
| unsigned int offset = id % BITS_PER_REG; |
| void __iomem *reg_addr; |
| unsigned long flags; |
| u32 reg; |
| |
| reg_addr = data->reg_base + data->param->level_offset + (bank << 2); |
| |
| spin_lock_irqsave(&data->lock, flags); |
| |
| reg = readl(reg_addr); |
| if (assert) |
| writel(reg & ~BIT(offset), reg_addr); |
| else |
| writel(reg | BIT(offset), reg_addr); |
| |
| spin_unlock_irqrestore(&data->lock, flags); |
| |
| return 0; |
| } |
| |
| static int meson_reset_assert(struct reset_controller_dev *rcdev, |
| unsigned long id) |
| { |
| return meson_reset_level(rcdev, id, true); |
| } |
| |
| static int meson_reset_deassert(struct reset_controller_dev *rcdev, |
| unsigned long id) |
| { |
| return meson_reset_level(rcdev, id, false); |
| } |
| |
| static const struct reset_control_ops meson_reset_ops = { |
| .reset = meson_reset_reset, |
| .assert = meson_reset_assert, |
| .deassert = meson_reset_deassert, |
| }; |
| |
| static const struct meson_reset_param meson8b_param = { |
| .reg_count = 8, |
| .level_offset = 0x7c, |
| }; |
| |
| static const struct meson_reset_param meson_a1_param = { |
| .reg_count = 3, |
| .level_offset = 0x40, |
| }; |
| |
| static const struct meson_reset_param meson_s4_param = { |
| .reg_count = 6, |
| .level_offset = 0x40, |
| }; |
| |
| static const struct of_device_id meson_reset_dt_ids[] = { |
| { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param}, |
| { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param}, |
| { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param}, |
| { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param}, |
| { .compatible = "amlogic,meson-s4-reset", .data = &meson_s4_param}, |
| { /* sentinel */ }, |
| }; |
| MODULE_DEVICE_TABLE(of, meson_reset_dt_ids); |
| |
| static int meson_reset_probe(struct platform_device *pdev) |
| { |
| struct meson_reset *data; |
| |
| data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
| if (!data) |
| return -ENOMEM; |
| |
| data->reg_base = devm_platform_ioremap_resource(pdev, 0); |
| if (IS_ERR(data->reg_base)) |
| return PTR_ERR(data->reg_base); |
| |
| data->param = of_device_get_match_data(&pdev->dev); |
| if (!data->param) |
| return -ENODEV; |
| |
| spin_lock_init(&data->lock); |
| |
| data->rcdev.owner = THIS_MODULE; |
| data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG; |
| data->rcdev.ops = &meson_reset_ops; |
| data->rcdev.of_node = pdev->dev.of_node; |
| |
| return devm_reset_controller_register(&pdev->dev, &data->rcdev); |
| } |
| |
| static struct platform_driver meson_reset_driver = { |
| .probe = meson_reset_probe, |
| .driver = { |
| .name = "meson_reset", |
| .of_match_table = meson_reset_dt_ids, |
| }, |
| }; |
| module_platform_driver(meson_reset_driver); |
| |
| MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver"); |
| MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); |
| MODULE_LICENSE("Dual BSD/GPL"); |