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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * BCM6345 Reset Controller Driver4 *5 * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>6 */7 8#include <linux/delay.h>9#include <linux/init.h>10#include <linux/io.h>11#include <linux/mod_devicetable.h>12#include <linux/platform_device.h>13#include <linux/reset-controller.h>14 15#define BCM6345_RESET_NUM 3216#define BCM6345_RESET_SLEEP_MIN_US 1000017#define BCM6345_RESET_SLEEP_MAX_US 2000018 19struct bcm6345_reset {20 struct reset_controller_dev rcdev;21 void __iomem *base;22 spinlock_t lock;23};24 25static inline struct bcm6345_reset *26to_bcm6345_reset(struct reset_controller_dev *rcdev)27{28 return container_of(rcdev, struct bcm6345_reset, rcdev);29}30 31static int bcm6345_reset_update(struct reset_controller_dev *rcdev,32 unsigned long id, bool assert)33{34 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);35 unsigned long flags;36 uint32_t val;37 38 spin_lock_irqsave(&bcm6345_reset->lock, flags);39 val = __raw_readl(bcm6345_reset->base);40 if (assert)41 val &= ~BIT(id);42 else43 val |= BIT(id);44 __raw_writel(val, bcm6345_reset->base);45 spin_unlock_irqrestore(&bcm6345_reset->lock, flags);46 47 return 0;48}49 50static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,51 unsigned long id)52{53 return bcm6345_reset_update(rcdev, id, true);54}55 56static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,57 unsigned long id)58{59 return bcm6345_reset_update(rcdev, id, false);60}61 62static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,63 unsigned long id)64{65 bcm6345_reset_update(rcdev, id, true);66 usleep_range(BCM6345_RESET_SLEEP_MIN_US,67 BCM6345_RESET_SLEEP_MAX_US);68 69 bcm6345_reset_update(rcdev, id, false);70 /*71 * Ensure component is taken out reset state by sleeping also after72 * deasserting the reset. Otherwise, the component may not be ready73 * for operation.74 */75 usleep_range(BCM6345_RESET_SLEEP_MIN_US,76 BCM6345_RESET_SLEEP_MAX_US);77 78 return 0;79}80 81static int bcm6345_reset_status(struct reset_controller_dev *rcdev,82 unsigned long id)83{84 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);85 86 return !(__raw_readl(bcm6345_reset->base) & BIT(id));87}88 89static const struct reset_control_ops bcm6345_reset_ops = {90 .assert = bcm6345_reset_assert,91 .deassert = bcm6345_reset_deassert,92 .reset = bcm6345_reset_reset,93 .status = bcm6345_reset_status,94};95 96static int bcm6345_reset_probe(struct platform_device *pdev)97{98 struct bcm6345_reset *bcm6345_reset;99 100 bcm6345_reset = devm_kzalloc(&pdev->dev,101 sizeof(*bcm6345_reset), GFP_KERNEL);102 if (!bcm6345_reset)103 return -ENOMEM;104 105 bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);106 if (IS_ERR(bcm6345_reset->base))107 return PTR_ERR(bcm6345_reset->base);108 109 spin_lock_init(&bcm6345_reset->lock);110 bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;111 bcm6345_reset->rcdev.owner = THIS_MODULE;112 bcm6345_reset->rcdev.of_node = pdev->dev.of_node;113 bcm6345_reset->rcdev.of_reset_n_cells = 1;114 bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;115 116 return devm_reset_controller_register(&pdev->dev,117 &bcm6345_reset->rcdev);118}119 120static const struct of_device_id bcm6345_reset_of_match[] = {121 { .compatible = "brcm,bcm6345-reset" },122 { /* sentinel */ },123};124 125static struct platform_driver bcm6345_reset_driver = {126 .probe = bcm6345_reset_probe,127 .driver = {128 .name = "bcm6345-reset",129 .of_match_table = bcm6345_reset_of_match,130 .suppress_bind_attrs = true,131 },132};133builtin_platform_driver(bcm6345_reset_driver);134