// 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");