drivers/char/nsc_gpio.c

Source file repositories/reference/linux-study-clean/drivers/char/nsc_gpio.c

File Facts

System
Linux kernel
Corpus path
drivers/char/nsc_gpio.c
Extension
.c
Size
3353 bytes
Lines
127
Domain
Driver Families
Bucket
drivers/char
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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

switch (c) {
		case '0':
			amp->gpio_set(m, 0);
			break;
		case '1':
			amp->gpio_set(m, 1);
			break;
		case 'O':
			dev_dbg(dev, "GPIO%d output enabled\n", m);
			amp->gpio_config(m, ~1, 1);
			break;
		case 'o':
			dev_dbg(dev, "GPIO%d output disabled\n", m);
			amp->gpio_config(m, ~1, 0);
			break;
		case 'T':
			dev_dbg(dev, "GPIO%d output is push pull\n", m);
			amp->gpio_config(m, ~2, 2);
			break;
		case 't':
			dev_dbg(dev, "GPIO%d output is open drain\n", m);
			amp->gpio_config(m, ~2, 0);
			break;
		case 'P':
			dev_dbg(dev, "GPIO%d pull up enabled\n", m);
			amp->gpio_config(m, ~4, 4);
			break;
		case 'p':
			dev_dbg(dev, "GPIO%d pull up disabled\n", m);
			amp->gpio_config(m, ~4, 0);
			break;
		case 'v':
			/* View Current pin settings */
			amp->gpio_dump(amp, m);
			break;
		case '\n':
			/* end of settings string, do nothing */
			break;
		default:
			dev_err(dev, "io%2d bad setting: chr<0x%2x>\n",
				m, (int)c);
			err++;
		}
	}
	if (err)
		return -EINVAL;	/* full string handled, report error */

	return len;
}

ssize_t nsc_gpio_read(struct file *file, char __user * buf,
		      size_t len, loff_t * ppos)
{
	unsigned m = iminor(file_inode(file));
	int value;
	struct nsc_gpio_ops *amp = file->private_data;

	value = amp->gpio_get(m);
	if (put_user(value ? '1' : '0', buf))
		return -EFAULT;

	return 1;
}

/* common file-ops routines for both scx200_gpio and pc87360_gpio */
EXPORT_SYMBOL(nsc_gpio_write);
EXPORT_SYMBOL(nsc_gpio_read);
EXPORT_SYMBOL(nsc_gpio_dump);

MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
MODULE_LICENSE("GPL");

Annotation

Implementation Notes