drivers/power/reset/syscon-reboot.c

Source file repositories/reference/linux-study-clean/drivers/power/reset/syscon-reboot.c

File Facts

System
Linux kernel
Corpus path
drivers/power/reset/syscon-reboot.c
Extension
.c
Size
3987 bytes
Lines
161
Domain
Driver Families
Bucket
drivers/power
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 reboot_mode_bits {
	u32 offset;
	u32 mask;
	u32 value;
	bool valid;
};

struct reboot_data {
	struct reboot_mode_bits mode_bits[REBOOT_SOFT + 1];
	struct reboot_mode_bits catchall;
};

struct syscon_reboot_context {
	struct regmap *map;

	const struct reboot_data *rd; /* from of match data, if any */
	struct reboot_mode_bits catchall; /* from DT */

	struct notifier_block restart_handler;
};

static int syscon_restart_handle(struct notifier_block *this,
					unsigned long mode, void *cmd)
{
	struct syscon_reboot_context *ctx =
			container_of(this, struct syscon_reboot_context,
					restart_handler);
	const struct reboot_mode_bits *mode_bits;

	if (ctx->rd) {
		if (mode < ARRAY_SIZE(ctx->rd->mode_bits) &&
		    ctx->rd->mode_bits[mode].valid)
			mode_bits = &ctx->rd->mode_bits[mode];
		else
			mode_bits = &ctx->rd->catchall;
	} else {
		mode_bits = &ctx->catchall;
	}

	/* Issue the reboot */
	regmap_update_bits(ctx->map, mode_bits->offset, mode_bits->mask,
			   mode_bits->value);

	mdelay(1000);

	pr_emerg("Unable to restart system\n");
	return NOTIFY_DONE;
}

static int syscon_reboot_probe(struct platform_device *pdev)
{
	struct syscon_reboot_context *ctx;
	struct device *dev = &pdev->dev;
	int priority;
	int err;

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

	ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
	if (IS_ERR(ctx->map)) {
		ctx->map = syscon_node_to_regmap(dev->parent->of_node);
		if (IS_ERR(ctx->map))
			return PTR_ERR(ctx->map);
	}

	if (of_property_read_s32(pdev->dev.of_node, "priority", &priority))
		priority = 192;

	ctx->rd = of_device_get_match_data(dev);
	if (!ctx->rd) {
		int mask_err, value_err;

		if (of_property_read_u32(pdev->dev.of_node, "offset",
					 &ctx->catchall.offset) &&
		    of_property_read_u32(pdev->dev.of_node, "reg",
					 &ctx->catchall.offset))
			return -EINVAL;

		value_err = of_property_read_u32(pdev->dev.of_node, "value",
						 &ctx->catchall.value);
		mask_err = of_property_read_u32(pdev->dev.of_node, "mask",
						&ctx->catchall.mask);
		if (value_err && mask_err) {
			dev_err(dev, "unable to read 'value' and 'mask'");
			return -EINVAL;
		}

		if (value_err) {

Annotation

Implementation Notes