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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Cirrus EP93xx SoC reset driver4 *5 * Copyright (C) 2021 Nikita Shubin <nikita.shubin@maquefel.me>6 */7 8#include <linux/bits.h>9#include <linux/container_of.h>10#include <linux/delay.h>11#include <linux/errno.h>12#include <linux/mfd/syscon.h>13#include <linux/module.h>14#include <linux/mod_devicetable.h>15#include <linux/notifier.h>16#include <linux/reboot.h>17#include <linux/slab.h>18 19#include <linux/soc/cirrus/ep93xx.h>20 21#define EP93XX_SYSCON_DEVCFG 0x8022#define EP93XX_SYSCON_DEVCFG_SWRST BIT(31)23 24struct ep93xx_restart {25 struct ep93xx_regmap_adev *aux_dev;26 struct notifier_block restart_handler;27};28 29static int ep93xx_restart_handle(struct notifier_block *this,30 unsigned long mode, void *cmd)31{32 struct ep93xx_restart *priv =33 container_of(this, struct ep93xx_restart, restart_handler);34 struct ep93xx_regmap_adev *aux = priv->aux_dev;35 36 /* Issue the reboot */37 aux->update_bits(aux->map, aux->lock, EP93XX_SYSCON_DEVCFG,38 EP93XX_SYSCON_DEVCFG_SWRST, EP93XX_SYSCON_DEVCFG_SWRST);39 aux->update_bits(aux->map, aux->lock, EP93XX_SYSCON_DEVCFG,40 EP93XX_SYSCON_DEVCFG_SWRST, 0);41 42 return NOTIFY_DONE;43}44 45static int ep93xx_reboot_probe(struct auxiliary_device *adev,46 const struct auxiliary_device_id *id)47{48 struct ep93xx_regmap_adev *rdev = to_ep93xx_regmap_adev(adev);49 struct device *dev = &adev->dev;50 struct ep93xx_restart *priv;51 int err;52 53 if (!rdev->update_bits)54 return -ENODEV;55 56 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);57 if (!priv)58 return -ENOMEM;59 60 priv->aux_dev = rdev;61 62 priv->restart_handler.notifier_call = ep93xx_restart_handle;63 priv->restart_handler.priority = 128;64 65 err = register_restart_handler(&priv->restart_handler);66 if (err)67 return dev_err_probe(dev, err, "can't register restart notifier\n");68 69 return 0;70}71 72static const struct auxiliary_device_id ep93xx_reboot_ids[] = {73 {74 .name = "soc_ep93xx.reset-ep93xx",75 },76 { /* sentinel */ }77};78MODULE_DEVICE_TABLE(auxiliary, ep93xx_reboot_ids);79 80static struct auxiliary_driver ep93xx_reboot_driver = {81 .probe = ep93xx_reboot_probe,82 .id_table = ep93xx_reboot_ids,83};84module_auxiliary_driver(ep93xx_reboot_driver);85