drivers/i2c/busses/i2c-elektor.c

Source file repositories/reference/linux-study-clean/drivers/i2c/busses/i2c-elektor.c

File Facts

System
Linux kernel
Corpus path
drivers/i2c/busses/i2c-elektor.c
Extension
.c
Size
8073 bytes
Lines
322
Domain
Driver Families
Bucket
drivers/i2c
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

if (pcf_pending == 0) {
			spin_unlock_irqrestore(&lock, flags);
			prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
			if (schedule_timeout(timeout*HZ)) {
				spin_lock_irqsave(&lock, flags);
				if (pcf_pending == 1) {
					pcf_pending = 0;
				}
				spin_unlock_irqrestore(&lock, flags);
			}
			finish_wait(&pcf_wait, &wait);
		} else {
			pcf_pending = 0;
			spin_unlock_irqrestore(&lock, flags);
		}
	} else {
		udelay(100);
	}
}


static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id) {
	spin_lock(&lock);
	pcf_pending = 1;
	spin_unlock(&lock);
	wake_up_interruptible(&pcf_wait);
	return IRQ_HANDLED;
}


static int pcf_isa_init(void)
{
	if (!mmapped) {
		if (!request_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested I/O region (%#x:2) is "
			       "in use\n", pcf_isa_ops.name, base);
			return -ENODEV;
		}
		base_iomem = ioport_map(base, 2);
		if (!base_iomem) {
			printk(KERN_ERR "%s: remap of I/O region %#x failed\n",
			       pcf_isa_ops.name, base);
			release_region(base, 2);
			return -ENODEV;
		}
	} else {
		if (!request_mem_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested memory region (%#x:2) "
			       "is in use\n", pcf_isa_ops.name, base);
			return -ENODEV;
		}
		base_iomem = ioremap(base, 2);
		if (base_iomem == NULL) {
			printk(KERN_ERR "%s: remap of memory region %#x "
			       "failed\n", pcf_isa_ops.name, base);
			release_mem_region(base, 2);
			return -ENODEV;
		}
	}
	pr_debug("%s: registers %#x remapped to %p\n", pcf_isa_ops.name, base,
		 base_iomem);

	if (irq > 0) {
		if (request_irq(irq, pcf_isa_handler, 0, pcf_isa_ops.name,
				NULL) < 0) {
			printk(KERN_ERR "%s: Request irq%d failed\n",
			       pcf_isa_ops.name, irq);
			irq = 0;
		} else
			enable_irq(irq);
	}
	return 0;
}

/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */
static struct i2c_algo_pcf_data pcf_isa_data = {
	.setpcf	    = pcf_isa_setbyte,
	.getpcf	    = pcf_isa_getbyte,
	.getown	    = pcf_isa_getown,
	.getclock   = pcf_isa_getclock,
	.waitforpin = pcf_isa_waitforpin,
};

static struct i2c_adapter pcf_isa_ops = {
	.owner		= THIS_MODULE,
	.class		= I2C_CLASS_HWMON,
	.algo_data	= &pcf_isa_data,

Annotation

Implementation Notes