system/ulib/ddktl/include/ddktl/protocol/clk.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <ddk/protocol/clk.h>
#include <ddktl/device-internal.h>
#include <zircon/assert.h>

#include "clk-internal.h"

// DDK clock protocol support.
//
// :: Proxies ::
//
// ddk::ClkProtocolProxy is a simple wrappers around clk_protocol_t. It does
// not own the pointers passed to it.
//
// :: Mixins ::
//
// ddk::ClkProtocol is a mixin class that simplifies writing DDK drivers that
// implement the clock protocol.
//
// :: Examples ::
//
// // A driver that implements a ZX_PROTOCOL_CLK device.
// class ClkDevice;
// using ClkDeviceType = ddk::Device<ClkDevice, /* ddk mixins */>;
//
// class ClkDevice : public ClkDeviceType,
//                   public ddk::ClkProtocol<ClkDevice> {
//   public:
//     ClkDevice(zx_device_t* parent)
//       : ClkDeviceType("my-clk-device", parent) {}
//
//        zx_status_t ClkEnable(uint32_t index);
//        zx_status_t ClkDisable(uint32_t index);
//     ...
// };

namespace ddk {

template <typename D>
class ClkProtocol {
public:
    ClkProtocol() {
        internal::CheckClkProtocolSubclass<D>();
        clk_proto_ops_.enable = ClkEnable;
        clk_proto_ops_.disable = ClkDisable;
    }

protected:
    clk_protocol_ops_t clk_proto_ops_ = {};

private:
    static zx_status_t ClkEnable(void* ctx, uint32_t index) {
        return static_cast<D*>(ctx)->ClkEnable(index);
    }
    static zx_status_t ClkDisable(void* ctx, uint32_t index) {
        return static_cast<D*>(ctx)->ClkDisable(index);
    }
};

class ClkProtocolProxy {
public:
    ClkProtocolProxy(clk_protocol_t* proto)
        : ops_(proto->ops), ctx_(proto->ctx) {}

    void GetProto(clk_protocol_t* proto) {
        proto->ctx = ctx_;
        proto->ops = ops_;
    }

    zx_status_t Enable(uint32_t index) {
        return ops_->enable(ctx_, index);
    }
    zx_status_t Disable(uint32_t index) {
        return ops_->disable(ctx_, index);
    }

private:
    clk_protocol_ops_t* ops_;
    void* ctx_;
};

} // namespace ddk