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1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause2/*3 * Amlogic Meson Reset Controller driver4 *5 * Copyright (c) 2016 BayLibre, SAS.6 * Author: Neil Armstrong <narmstrong@baylibre.com>7 */8#include <linux/err.h>9#include <linux/init.h>10#include <linux/io.h>11#include <linux/of.h>12#include <linux/module.h>13#include <linux/platform_device.h>14#include <linux/reset-controller.h>15#include <linux/slab.h>16#include <linux/types.h>17 18#define BITS_PER_REG 3219 20struct meson_reset_param {21 int reg_count;22 int level_offset;23};24 25struct meson_reset {26 void __iomem *reg_base;27 const struct meson_reset_param *param;28 struct reset_controller_dev rcdev;29 spinlock_t lock;30};31 32static int meson_reset_reset(struct reset_controller_dev *rcdev,33 unsigned long id)34{35 struct meson_reset *data =36 container_of(rcdev, struct meson_reset, rcdev);37 unsigned int bank = id / BITS_PER_REG;38 unsigned int offset = id % BITS_PER_REG;39 void __iomem *reg_addr = data->reg_base + (bank << 2);40 41 writel(BIT(offset), reg_addr);42 43 return 0;44}45 46static int meson_reset_level(struct reset_controller_dev *rcdev,47 unsigned long id, bool assert)48{49 struct meson_reset *data =50 container_of(rcdev, struct meson_reset, rcdev);51 unsigned int bank = id / BITS_PER_REG;52 unsigned int offset = id % BITS_PER_REG;53 void __iomem *reg_addr;54 unsigned long flags;55 u32 reg;56 57 reg_addr = data->reg_base + data->param->level_offset + (bank << 2);58 59 spin_lock_irqsave(&data->lock, flags);60 61 reg = readl(reg_addr);62 if (assert)63 writel(reg & ~BIT(offset), reg_addr);64 else65 writel(reg | BIT(offset), reg_addr);66 67 spin_unlock_irqrestore(&data->lock, flags);68 69 return 0;70}71 72static int meson_reset_assert(struct reset_controller_dev *rcdev,73 unsigned long id)74{75 return meson_reset_level(rcdev, id, true);76}77 78static int meson_reset_deassert(struct reset_controller_dev *rcdev,79 unsigned long id)80{81 return meson_reset_level(rcdev, id, false);82}83 84static const struct reset_control_ops meson_reset_ops = {85 .reset = meson_reset_reset,86 .assert = meson_reset_assert,87 .deassert = meson_reset_deassert,88};89 90static const struct meson_reset_param meson8b_param = {91 .reg_count = 8,92 .level_offset = 0x7c,93};94 95static const struct meson_reset_param meson_a1_param = {96 .reg_count = 3,97 .level_offset = 0x40,98};99 100static const struct meson_reset_param meson_s4_param = {101 .reg_count = 6,102 .level_offset = 0x40,103};104 105static const struct meson_reset_param t7_param = {106 .reg_count = 7,107 .level_offset = 0x40,108};109 110static const struct of_device_id meson_reset_dt_ids[] = {111 { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param},112 { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},113 { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param},114 { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param},115 { .compatible = "amlogic,meson-s4-reset", .data = &meson_s4_param},116 { .compatible = "amlogic,c3-reset", .data = &meson_s4_param},117 { .compatible = "amlogic,t7-reset", .data = &t7_param},118 { /* sentinel */ },119};120MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);121 122static int meson_reset_probe(struct platform_device *pdev)123{124 struct meson_reset *data;125 126 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);127 if (!data)128 return -ENOMEM;129 130 data->reg_base = devm_platform_ioremap_resource(pdev, 0);131 if (IS_ERR(data->reg_base))132 return PTR_ERR(data->reg_base);133 134 data->param = of_device_get_match_data(&pdev->dev);135 if (!data->param)136 return -ENODEV;137 138 spin_lock_init(&data->lock);139 140 data->rcdev.owner = THIS_MODULE;141 data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;142 data->rcdev.ops = &meson_reset_ops;143 data->rcdev.of_node = pdev->dev.of_node;144 145 return devm_reset_controller_register(&pdev->dev, &data->rcdev);146}147 148static struct platform_driver meson_reset_driver = {149 .probe = meson_reset_probe,150 .driver = {151 .name = "meson_reset",152 .of_match_table = meson_reset_dt_ids,153 },154};155module_platform_driver(meson_reset_driver);156 157MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");158MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");159MODULE_LICENSE("Dual BSD/GPL");160