drivers/media/usb/cx231xx/cx231xx-input.c

Source file repositories/reference/linux-study-clean/drivers/media/usb/cx231xx/cx231xx-input.c

File Facts

System
Linux kernel
Corpus path
drivers/media/usb/cx231xx/cx231xx-input.c
Extension
.c
Size
2666 bytes
Lines
102
Domain
Driver Families
Bucket
drivers/media
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

// SPDX-License-Identifier: GPL-2.0
// cx231xx IR glue driver
//
// Copyright (c) 2010 Mauro Carvalho Chehab <mchehab@kernel.org>
//
// Polaris (cx231xx) has its support for IR's with a design close to MCE.
// however, a few designs are using an external I2C chip for IR, instead
// of using the one provided by the chip.
// This driver provides support for those extra devices

#include "cx231xx.h"
#include <linux/slab.h>
#include <linux/bitrev.h>

#define MODULE_NAME "cx231xx-input"

static int get_key_isdbt(struct IR_i2c *ir, enum rc_proto *protocol,
			 u32 *pscancode, u8 *toggle)
{
	int	rc;
	u8	cmd, scancode;

	dev_dbg(&ir->rc->dev, "%s\n", __func__);

		/* poll IR chip */
	rc = i2c_master_recv(ir->c, &cmd, 1);
	if (rc < 0)
		return rc;
	if (rc != 1)
		return -EIO;

	/* it seems that 0xFE indicates that a button is still hold
	   down, while 0xff indicates that no button is hold
	   down. 0xfe sequences are sometimes interrupted by 0xFF */

	if (cmd == 0xff)
		return 0;

	scancode = bitrev8(cmd);

	dev_dbg(&ir->rc->dev, "cmd %02x, scan = %02x\n", cmd, scancode);

	*protocol = RC_PROTO_OTHER;
	*pscancode = scancode;
	*toggle = 0;
	return 1;
}

int cx231xx_ir_init(struct cx231xx *dev)
{
	struct i2c_board_info info;
	u8 ir_i2c_bus;

	dev_dbg(dev->dev, "%s\n", __func__);

	/* Only initialize if a rc keycode map is defined */
	if (!cx231xx_boards[dev->model].rc_map_name)
		return -ENODEV;

	request_module("ir-kbd-i2c");

	memset(&info, 0, sizeof(struct i2c_board_info));
	memset(&dev->init_data, 0, sizeof(dev->init_data));
	dev->init_data.rc_dev = rc_allocate_device(RC_DRIVER_SCANCODE);
	if (!dev->init_data.rc_dev)
		return -ENOMEM;

	dev->init_data.name = cx231xx_boards[dev->model].name;

	strscpy(info.type, "ir_video", I2C_NAME_SIZE);
	info.platform_data = &dev->init_data;

	/*
	 * Board-dependent values
	 *
	 * For now, there's just one type of hardware design using
	 * an i2c device.
	 */
	dev->init_data.get_key = get_key_isdbt;
	dev->init_data.ir_codes = cx231xx_boards[dev->model].rc_map_name;
	/* The i2c micro-controller only outputs the cmd part of NEC protocol */
	dev->init_data.rc_dev->scancode_mask = 0xff;
	dev->init_data.rc_dev->driver_name = "cx231xx";
	dev->init_data.type = RC_PROTO_BIT_NEC;
	info.addr = 0x30;

	/* Load and bind ir-kbd-i2c */
	ir_i2c_bus = cx231xx_boards[dev->model].ir_i2c_master;
	dev_dbg(dev->dev, "Trying to bind ir at bus %d, addr 0x%02x\n",
		ir_i2c_bus, info.addr);

Annotation

Implementation Notes