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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 <[email protected]>");
- MODULE_DESCRIPTION("ARM SCMI reset controller driver");
- MODULE_LICENSE("GPL v2");
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