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// SPDX-License-Identifier: GPL-2.0
/*
* ARM System Control and Management Interface (ARM SCMI) reset driver
*
* Copyright (C) 2019-2021 ARM Ltd.
*/
#include <linux/module.h>
#include <linux/of.h>
#include <linux/device.h>
#include <linux/reset-controller.h>
#include <linux/scmi_protocol.h>
static const struct scmi_reset_proto_ops *reset_ops;
/**
* struct scmi_reset_data - reset controller information structure
* @rcdev: reset controller entity
* @ph: ARM SCMI protocol handle used for communication with system controller
*/
struct scmi_reset_data {
struct reset_controller_dev rcdev;
const struct scmi_protocol_handle *ph;
};
#define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev)
#define to_scmi_handle(p) (to_scmi_reset_data(p)->ph)
/**
* scmi_reset_assert() - assert device reset
* @rcdev: reset controller entity
* @id: ID of the reset to be asserted
*
* This function implements the reset driver op to assert a device's reset
* using the ARM SCMI protocol.
*
* Return: 0 for successful request, else a corresponding error value
*/
static int
scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
{
const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
return reset_ops->assert(ph, id);
}
/**
* scmi_reset_deassert() - deassert device reset
* @rcdev: reset controller entity
* @id: ID of the reset to be deasserted
*
* This function implements the reset driver op to deassert a device's reset
* using the ARM SCMI protocol.
*
* Return: 0 for successful request, else a corresponding error value
*/
static int
scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
{
const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
return reset_ops->deassert(ph, id);
}
/**
* scmi_reset_reset() - reset the device
* @rcdev: reset controller entity
* @id: ID of the reset signal to be reset(assert + deassert)
*
* This function implements the reset driver op to trigger a device's
* reset signal using the ARM SCMI protocol.
*
* Return: 0 for successful request, else a corresponding error value
*/
static int
scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
{
const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
return reset_ops->reset(ph, id);
}
static const struct reset_control_ops scmi_reset_ops = {
.assert = scmi_reset_assert,
.deassert = scmi_reset_deassert,
.reset = scmi_reset_reset,
};
static int scmi_reset_probe(struct scmi_device *sdev)
{
struct scmi_reset_data *data;
struct device *dev = &sdev->dev;
struct device_node *np = dev->of_node;
const struct scmi_handle *handle = sdev->handle;
struct scmi_protocol_handle *ph;
if (!handle)
return -ENODEV;
reset_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_RESET, &ph);
if (IS_ERR(reset_ops))
return PTR_ERR(reset_ops);
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->rcdev.ops = &scmi_reset_ops;
data->rcdev.owner = THIS_MODULE;
data->rcdev.of_node = np;
data->rcdev.nr_resets = reset_ops->num_domains_get(ph);
data->ph = ph;
return devm_reset_controller_register(dev, &data->rcdev);
}
static const struct scmi_device_id scmi_id_table[] = {
{ SCMI_PROTOCOL_RESET, "reset" },
{ },
};
MODULE_DEVICE_TABLE(scmi, scmi_id_table);
static struct scmi_driver scmi_reset_driver = {
.name = "scmi-reset",
.probe = scmi_reset_probe,
.id_table = scmi_id_table,
};
module_scmi_driver(scmi_reset_driver);
MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCMI reset controller driver");
MODULE_LICENSE("GPL v2");
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