drivers/clk/tegra/clk-audio-sync.c

Source file repositories/reference/linux-study-clean/drivers/clk/tegra/clk-audio-sync.c

File Facts

System
Linux kernel
Corpus path
drivers/clk/tegra/clk-audio-sync.c
Extension
.c
Size
1691 bytes
Lines
76
Domain
Driver Families
Bucket
drivers/clk
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/err.h>

#include "clk.h"

static unsigned long clk_sync_source_recalc_rate(struct clk_hw *hw,
						 unsigned long parent_rate)
{
	struct tegra_clk_sync_source *sync = to_clk_sync_source(hw);

	return sync->rate;
}

static int clk_sync_source_determine_rate(struct clk_hw *hw,
					  struct clk_rate_request *req)
{
	struct tegra_clk_sync_source *sync = to_clk_sync_source(hw);

	if (req->rate > sync->max_rate)
		return -EINVAL;
	else
		return 0;
}

static int clk_sync_source_set_rate(struct clk_hw *hw, unsigned long rate,
				    unsigned long parent_rate)
{
	struct tegra_clk_sync_source *sync = to_clk_sync_source(hw);

	sync->rate = rate;
	return 0;
}

const struct clk_ops tegra_clk_sync_source_ops = {
	.determine_rate = clk_sync_source_determine_rate,
	.set_rate = clk_sync_source_set_rate,
	.recalc_rate = clk_sync_source_recalc_rate,
};

struct clk *tegra_clk_register_sync_source(const char *name,
					   unsigned long max_rate)
{
	struct tegra_clk_sync_source *sync;
	struct clk_init_data init;
	struct clk *clk;

	sync = kzalloc_obj(*sync);
	if (!sync) {
		pr_err("%s: could not allocate sync source clk\n", __func__);
		return ERR_PTR(-ENOMEM);
	}

	sync->max_rate = max_rate;

	init.ops = &tegra_clk_sync_source_ops;
	init.name = name;
	init.flags = 0;
	init.parent_names = NULL;
	init.num_parents = 0;

	/* Data in .init is copied by clk_register(), so stack variable OK */
	sync->hw.init = &init;

	clk = clk_register(NULL, &sync->hw);
	if (IS_ERR(clk))
		kfree(sync);

	return clk;
}

Annotation

Implementation Notes