drivers/media/pci/bt8xx/bttv-if.c

Source file repositories/reference/linux-study-clean/drivers/media/pci/bt8xx/bttv-if.c

File Facts

System
Linux kernel
Corpus path
drivers/media/pci/bt8xx/bttv-if.c
Extension
.c
Size
2178 bytes
Lines
104
Domain
Driver Families
Bucket
drivers/media
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

// SPDX-License-Identifier: GPL-2.0-or-later
/*

    bttv-if.c  --  old gpio interface to other kernel modules
		   don't use in new code, will go away in 2.7
		   have a look at bttv-gpio.c instead.

    bttv - Bt848 frame grabber driver

    Copyright (C) 1996,97,98 Ralph  Metzler (rjkm@thp.uni-koeln.de)
			   & Marcus Metzler (mocm@thp.uni-koeln.de)
    (c) 1999-2003 Gerd Knorr <kraxel@bytesex.org>


*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/io.h>

#include "bttvp.h"

EXPORT_SYMBOL(bttv_get_pcidev);
EXPORT_SYMBOL(bttv_gpio_enable);
EXPORT_SYMBOL(bttv_read_gpio);
EXPORT_SYMBOL(bttv_write_gpio);

/* ----------------------------------------------------------------------- */
/* Exported functions - for other modules which want to access the         */
/*                      gpio ports (IR for example)                        */
/*                      see bttv.h for comments                            */

struct pci_dev* bttv_get_pcidev(unsigned int card)
{
	if (card >= bttv_num)
		return NULL;
	if (!bttvs[card])
		return NULL;

	return bttvs[card]->c.pci;
}


int bttv_gpio_enable(unsigned int card, unsigned long mask, unsigned long data)
{
	struct bttv *btv;

	if (card >= bttv_num) {
		return -EINVAL;
	}

	btv = bttvs[card];
	if (!btv)
		return -ENODEV;

	gpio_inout(mask,data);
	if (bttv_gpio)
		bttv_gpio_tracking(btv,"extern enable");
	return 0;
}

int bttv_read_gpio(unsigned int card, unsigned long *data)
{
	struct bttv *btv;

	if (card >= bttv_num) {
		return -EINVAL;
	}

	btv = bttvs[card];
	if (!btv)
		return -ENODEV;

	if(btv->shutdown) {
		return -ENODEV;
	}

/* prior setting BT848_GPIO_REG_INP is (probably) not needed
   because we set direct input on init */
	*data = gpio_read();
	return 0;
}

int bttv_write_gpio(unsigned int card, unsigned long mask, unsigned long data)
{
	struct bttv *btv;

	if (card >= bttv_num) {
		return -EINVAL;

Annotation

Implementation Notes