drivers/media/pci/cx25821/cx25821-gpio.c

Source file repositories/reference/linux-study-clean/drivers/media/pci/cx25821/cx25821-gpio.c

File Facts

System
Linux kernel
Corpus path
drivers/media/pci/cx25821/cx25821-gpio.c
Extension
.c
Size
1847 bytes
Lines
86
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
/*
 *  Driver for the Conexant CX25821 PCIe bridge
 *
 *  Copyright (C) 2009 Conexant Systems Inc.
 *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
 */

#include <linux/module.h>
#include "cx25821.h"

/********************* GPIO stuffs *********************/
void cx25821_set_gpiopin_direction(struct cx25821_dev *dev,
				   int pin_number, int pin_logic_value)
{
	int bit = pin_number;
	u32 gpio_oe_reg = GPIO_LO_OE;
	u32 gpio_register = 0;
	u32 value = 0;

	/* Check for valid pinNumber */
	if (pin_number >= 47)
		return;

	if (pin_number > 31) {
		bit = pin_number - 31;
		gpio_oe_reg = GPIO_HI_OE;
	}
	/* Here we will make sure that the GPIOs 0 and 1 are output. keep the
	 * rest as is */
	gpio_register = cx_read(gpio_oe_reg);

	if (pin_logic_value == 1)
		value = gpio_register | Set_GPIO_Bit(bit);
	else
		value = gpio_register & Clear_GPIO_Bit(bit);

	cx_write(gpio_oe_reg, value);
}
EXPORT_SYMBOL(cx25821_set_gpiopin_direction);

static void cx25821_set_gpiopin_logicvalue(struct cx25821_dev *dev,
					   int pin_number, int pin_logic_value)
{
	int bit = pin_number;
	u32 gpio_reg = GPIO_LO;
	u32 value = 0;

	/* Check for valid pinNumber */
	if (pin_number >= 47)
		return;

	/* change to output direction */
	cx25821_set_gpiopin_direction(dev, pin_number, 0);

	if (pin_number > 31) {
		bit = pin_number - 31;
		gpio_reg = GPIO_HI;
	}

	value = cx_read(gpio_reg);

	if (pin_logic_value == 0)
		value &= Clear_GPIO_Bit(bit);
	else
		value |= Set_GPIO_Bit(bit);

	cx_write(gpio_reg, value);
}

void cx25821_gpio_init(struct cx25821_dev *dev)
{
	if (dev == NULL)
		return;

	switch (dev->board) {
	case CX25821_BOARD_CONEXANT_ATHENA10:
	default:
		/* set GPIO 5 to select the path for Medusa/Athena */
		cx25821_set_gpiopin_logicvalue(dev, 5, 1);
		msleep(20);
		break;
	}

}

Annotation

Implementation Notes