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1// SPDX-License-Identifier: GPL-2.02/*3 * ARM System Control and Management Interface (ARM SCMI) reset driver4 *5 * Copyright (C) 2019-2021 ARM Ltd.6 */7 8#include <linux/module.h>9#include <linux/of.h>10#include <linux/device.h>11#include <linux/reset-controller.h>12#include <linux/scmi_protocol.h>13 14static const struct scmi_reset_proto_ops *reset_ops;15 16/**17 * struct scmi_reset_data - reset controller information structure18 * @rcdev: reset controller entity19 * @ph: ARM SCMI protocol handle used for communication with system controller20 */21struct scmi_reset_data {22 struct reset_controller_dev rcdev;23 const struct scmi_protocol_handle *ph;24};25 26#define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev)27#define to_scmi_handle(p) (to_scmi_reset_data(p)->ph)28 29/**30 * scmi_reset_assert() - assert device reset31 * @rcdev: reset controller entity32 * @id: ID of the reset to be asserted33 *34 * This function implements the reset driver op to assert a device's reset35 * using the ARM SCMI protocol.36 *37 * Return: 0 for successful request, else a corresponding error value38 */39static int40scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)41{42 const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);43 44 return reset_ops->assert(ph, id);45}46 47/**48 * scmi_reset_deassert() - deassert device reset49 * @rcdev: reset controller entity50 * @id: ID of the reset to be deasserted51 *52 * This function implements the reset driver op to deassert a device's reset53 * using the ARM SCMI protocol.54 *55 * Return: 0 for successful request, else a corresponding error value56 */57static int58scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)59{60 const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);61 62 return reset_ops->deassert(ph, id);63}64 65/**66 * scmi_reset_reset() - reset the device67 * @rcdev: reset controller entity68 * @id: ID of the reset signal to be reset(assert + deassert)69 *70 * This function implements the reset driver op to trigger a device's71 * reset signal using the ARM SCMI protocol.72 *73 * Return: 0 for successful request, else a corresponding error value74 */75static int76scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)77{78 const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);79 80 return reset_ops->reset(ph, id);81}82 83static const struct reset_control_ops scmi_reset_ops = {84 .assert = scmi_reset_assert,85 .deassert = scmi_reset_deassert,86 .reset = scmi_reset_reset,87};88 89static int scmi_reset_probe(struct scmi_device *sdev)90{91 struct scmi_reset_data *data;92 struct device *dev = &sdev->dev;93 struct device_node *np = dev->of_node;94 const struct scmi_handle *handle = sdev->handle;95 struct scmi_protocol_handle *ph;96 97 if (!handle)98 return -ENODEV;99 100 reset_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_RESET, &ph);101 if (IS_ERR(reset_ops))102 return PTR_ERR(reset_ops);103 104 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);105 if (!data)106 return -ENOMEM;107 108 data->rcdev.ops = &scmi_reset_ops;109 data->rcdev.owner = THIS_MODULE;110 data->rcdev.of_node = np;111 data->rcdev.nr_resets = reset_ops->num_domains_get(ph);112 data->ph = ph;113 114 return devm_reset_controller_register(dev, &data->rcdev);115}116 117static const struct scmi_device_id scmi_id_table[] = {118 { SCMI_PROTOCOL_RESET, "reset" },119 { },120};121MODULE_DEVICE_TABLE(scmi, scmi_id_table);122 123static struct scmi_driver scmi_reset_driver = {124 .name = "scmi-reset",125 .probe = scmi_reset_probe,126 .id_table = scmi_id_table,127};128module_scmi_driver(scmi_reset_driver);129 130MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");131MODULE_DESCRIPTION("ARM SCMI reset controller driver");132MODULE_LICENSE("GPL v2");133