drivers/bus/simple-pm-bus.c

Source file repositories/reference/linux-study-clean/drivers/bus/simple-pm-bus.c

File Facts

System
Linux kernel
Corpus path
drivers/bus/simple-pm-bus.c
Extension
.c
Size
4545 bytes
Lines
169
Domain
Driver Families
Bucket
drivers/bus
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

struct simple_pm_bus {
	struct clk_bulk_data *clks;
	int num_clks;
};

static int simple_pm_bus_probe(struct platform_device *pdev)
{
	const struct device *dev = &pdev->dev;
	const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
	struct device_node *np = dev->of_node;
	const struct of_device_id *match;
	struct simple_pm_bus *bus;

	/*
	 * Allow user to use driver_override to bind this driver to a
	 * transparent bus device which has a different compatible string
	 * that's not listed in simple_pm_bus_of_match. We don't want to do any
	 * of the simple-pm-bus tasks for these devices, so return early.
	 */
	if (device_has_driver_override(&pdev->dev))
		return 0;

	match = of_match_device(dev->driver->of_match_table, dev);
	/*
	 * These are transparent bus devices (not simple-pm-bus matches) that
	 * have their child nodes populated automatically.  So, don't need to
	 * do anything more. We only match with the device if this driver is
	 * the most specific match because we don't want to incorrectly bind to
	 * a device that has a more specific driver.
	 */
	if (match && match->data) {
		if (of_property_match_string(np, "compatible", match->compatible) == 0)
			return 0;
		else
			return -ENODEV;
	}

	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
	if (!bus)
		return -ENOMEM;

	bus->num_clks = devm_clk_bulk_get_all(&pdev->dev, &bus->clks);
	if (bus->num_clks < 0)
		return dev_err_probe(&pdev->dev, bus->num_clks, "failed to get clocks\n");

	dev_set_drvdata(&pdev->dev, bus);

	dev_dbg(&pdev->dev, "%s\n", __func__);

	pm_runtime_enable(&pdev->dev);

	if (np)
		of_platform_populate(np, NULL, lookup, &pdev->dev);

	return 0;
}

static void simple_pm_bus_remove(struct platform_device *pdev)
{
	const void *data = of_device_get_match_data(&pdev->dev);

	if (device_has_driver_override(&pdev->dev) || data)
		return;

	dev_dbg(&pdev->dev, "%s\n", __func__);

	pm_runtime_disable(&pdev->dev);
}

static int simple_pm_bus_runtime_suspend(struct device *dev)
{
	struct simple_pm_bus *bus = dev_get_drvdata(dev);

	clk_bulk_disable_unprepare(bus->num_clks, bus->clks);

	return 0;
}

static int simple_pm_bus_runtime_resume(struct device *dev)
{
	struct simple_pm_bus *bus = dev_get_drvdata(dev);
	int ret;

	ret = clk_bulk_prepare_enable(bus->num_clks, bus->clks);
	if (ret) {
		dev_err(dev, "failed to enable clocks: %d\n", ret);
		return ret;
	}

	return 0;

Annotation

Implementation Notes