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1// SPDX-License-Identifier: GPL-2.02/*3 * Broadcom STB generic reset controller for SW_INIT style reset controller4 *5 * Author: Florian Fainelli <f.fainelli@gmail.com>6 * Copyright (C) 2018 Broadcom7 */8#include <linux/delay.h>9#include <linux/device.h>10#include <linux/io.h>11#include <linux/module.h>12#include <linux/of.h>13#include <linux/platform_device.h>14#include <linux/reset-controller.h>15#include <linux/types.h>16 17struct brcmstb_reset {18 void __iomem *base;19 struct reset_controller_dev rcdev;20};21 22#define SW_INIT_SET 0x0023#define SW_INIT_CLEAR 0x0424#define SW_INIT_STATUS 0x0825 26#define SW_INIT_BIT(id) BIT((id) & 0x1f)27#define SW_INIT_BANK(id) ((id) >> 5)28 29/* A full bank contains extra registers that we are not utilizing but still30 * qualify as a single bank.31 */32#define SW_INIT_BANK_SIZE 0x1833 34static inline35struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)36{37 return container_of(rcdev, struct brcmstb_reset, rcdev);38}39 40static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,41 unsigned long id)42{43 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;44 struct brcmstb_reset *priv = to_brcmstb(rcdev);45 46 writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);47 48 return 0;49}50 51static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,52 unsigned long id)53{54 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;55 struct brcmstb_reset *priv = to_brcmstb(rcdev);56 57 writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);58 /* Maximum reset delay after de-asserting a line and seeing block59 * operation is typically 14us for the worst case, build some slack60 * here.61 */62 usleep_range(100, 200);63 64 return 0;65}66 67static int brcmstb_reset_status(struct reset_controller_dev *rcdev,68 unsigned long id)69{70 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;71 struct brcmstb_reset *priv = to_brcmstb(rcdev);72 73 return readl_relaxed(priv->base + off + SW_INIT_STATUS) &74 SW_INIT_BIT(id);75}76 77static const struct reset_control_ops brcmstb_reset_ops = {78 .assert = brcmstb_reset_assert,79 .deassert = brcmstb_reset_deassert,80 .status = brcmstb_reset_status,81};82 83static int brcmstb_reset_probe(struct platform_device *pdev)84{85 struct device *kdev = &pdev->dev;86 struct brcmstb_reset *priv;87 struct resource *res;88 89 priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);90 if (!priv)91 return -ENOMEM;92 93 priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);94 if (IS_ERR(priv->base))95 return PTR_ERR(priv->base);96 97 dev_set_drvdata(kdev, priv);98 99 priv->rcdev.owner = THIS_MODULE;100 priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),101 SW_INIT_BANK_SIZE) * 32;102 priv->rcdev.ops = &brcmstb_reset_ops;103 priv->rcdev.of_node = kdev->of_node;104 /* Use defaults: 1 cell and simple xlate function */105 106 return devm_reset_controller_register(kdev, &priv->rcdev);107}108 109static const struct of_device_id brcmstb_reset_of_match[] = {110 { .compatible = "brcm,brcmstb-reset" },111 { /* sentinel */ }112};113MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match);114 115static struct platform_driver brcmstb_reset_driver = {116 .probe = brcmstb_reset_probe,117 .driver = {118 .name = "brcmstb-reset",119 .of_match_table = brcmstb_reset_of_match,120 },121};122module_platform_driver(brcmstb_reset_driver);123 124MODULE_AUTHOR("Broadcom");125MODULE_DESCRIPTION("Broadcom STB reset controller");126MODULE_LICENSE("GPL");127