drivers/misc/ad525x_dpot-spi.c

Source file repositories/reference/linux-study-clean/drivers/misc/ad525x_dpot-spi.c

File Facts

System
Linux kernel
Corpus path
drivers/misc/ad525x_dpot-spi.c
Extension
.c
Size
2879 bytes
Lines
146
Domain
Driver Families
Bucket
drivers/misc
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-or-later
/*
 * Driver for the Analog Devices digital potentiometers (SPI bus)
 *
 * Copyright (C) 2010-2011 Michael Hennerich, Analog Devices Inc.
 */

#include <linux/spi/spi.h>
#include <linux/module.h>

#include "ad525x_dpot.h"

/* SPI bus functions */
static int write8(void *client, u8 val)
{
	u8 data = val;

	return spi_write(client, &data, 1);
}

static int write16(void *client, u8 reg, u8 val)
{
	u8 data[2] = {reg, val};

	return spi_write(client, data, 2);
}

static int write24(void *client, u8 reg, u16 val)
{
	u8 data[3] = {reg, val >> 8, val};

	return spi_write(client, data, 3);
}

static int read8(void *client)
{
	int ret;
	u8 data;

	ret = spi_read(client, &data, 1);
	if (ret < 0)
		return ret;

	return data;
}

static int read16(void *client, u8 reg)
{
	int ret;
	u8 buf_rx[2];

	write16(client, reg, 0);
	ret = spi_read(client, buf_rx, 2);
	if (ret < 0)
		return ret;

	return (buf_rx[0] << 8) |  buf_rx[1];
}

static int read24(void *client, u8 reg)
{
	int ret;
	u8 buf_rx[3];

	write24(client, reg, 0);
	ret = spi_read(client, buf_rx, 3);
	if (ret < 0)
		return ret;

	return (buf_rx[1] << 8) |  buf_rx[2];
}

static const struct ad_dpot_bus_ops bops = {
	.read_d8	= read8,
	.read_r8d8	= read16,
	.read_r8d16	= read24,
	.write_d8	= write8,
	.write_r8d8	= write16,
	.write_r8d16	= write24,
};
static int ad_dpot_spi_probe(struct spi_device *spi)
{
	struct ad_dpot_bus_data bdata = {
		.client = spi,
		.bops = &bops,
	};

	return ad_dpot_probe(&spi->dev, &bdata,
			     spi_get_device_id(spi)->driver_data,
			     spi_get_device_id(spi)->name);

Annotation

Implementation Notes