drivers/input/serio/ambakmi.c

Source file repositories/reference/linux-study-clean/drivers/input/serio/ambakmi.c

File Facts

System
Linux kernel
Corpus path
drivers/input/serio/ambakmi.c
Extension
.c
Size
4215 bytes
Lines
210
Domain
Driver Families
Bucket
drivers/input
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 amba_kmi_port {
	struct serio		*io;
	struct clk		*clk;
	void __iomem		*base;
	unsigned int		irq;
	unsigned int		divisor;
	unsigned int		open;
};

static irqreturn_t amba_kmi_int(int irq, void *dev_id)
{
	struct amba_kmi_port *kmi = dev_id;
	unsigned int status = readb(KMIIR);
	int handled = IRQ_NONE;

	while (status & KMIIR_RXINTR) {
		serio_interrupt(kmi->io, readb(KMIDATA), 0);
		status = readb(KMIIR);
		handled = IRQ_HANDLED;
	}

	return handled;
}

static int amba_kmi_write(struct serio *io, unsigned char val)
{
	struct amba_kmi_port *kmi = io->port_data;
	unsigned int timeleft = 10000; /* timeout in 100ms */

	while ((readb(KMISTAT) & KMISTAT_TXEMPTY) == 0 && --timeleft)
		udelay(10);

	if (timeleft)
		writeb(val, KMIDATA);

	return timeleft ? 0 : SERIO_TIMEOUT;
}

static int amba_kmi_open(struct serio *io)
{
	struct amba_kmi_port *kmi = io->port_data;
	unsigned int divisor;
	int ret;

	ret = clk_prepare_enable(kmi->clk);
	if (ret)
		goto out;

	divisor = clk_get_rate(kmi->clk) / 8000000 - 1;
	writeb(divisor, KMICLKDIV);
	writeb(KMICR_EN, KMICR);

	ret = request_irq(kmi->irq, amba_kmi_int, IRQF_SHARED, "kmi-pl050",
			  kmi);
	if (ret) {
		printk(KERN_ERR "kmi: failed to claim IRQ%d\n", kmi->irq);
		writeb(0, KMICR);
		goto clk_disable;
	}

	writeb(KMICR_EN | KMICR_RXINTREN, KMICR);

	return 0;

 clk_disable:
	clk_disable_unprepare(kmi->clk);
 out:
	return ret;
}

static void amba_kmi_close(struct serio *io)
{
	struct amba_kmi_port *kmi = io->port_data;

	writeb(0, KMICR);

	free_irq(kmi->irq, kmi);
	clk_disable_unprepare(kmi->clk);
}

static int amba_kmi_probe(struct amba_device *dev,
	const struct amba_id *id)
{
	struct amba_kmi_port *kmi;
	struct serio *io;
	int ret;

	ret = amba_request_regions(dev, NULL);
	if (ret)
		return ret;

Annotation

Implementation Notes