drivers/iio/dac/ad5592r.c

Source file repositories/reference/linux-study-clean/drivers/iio/dac/ad5592r.c

File Facts

System
Linux kernel
Corpus path
drivers/iio/dac/ad5592r.c
Extension
.c
Size
4055 bytes
Lines
172
Domain
Driver Families
Bucket
drivers/iio
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-only
/*
 * AD5592R Digital <-> Analog converters driver
 *
 * Copyright 2015-2016 Analog Devices Inc.
 * Author: Paul Cercueil <paul.cercueil@analog.com>
 */

#include "ad5592r-base.h"

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

#define AD5592R_GPIO_READBACK_EN	BIT(10)
#define AD5592R_LDAC_READBACK_EN	BIT(6)

static int ad5592r_spi_wnop_r16(struct ad5592r_state *st, __be16 *buf)
{
	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
	struct spi_transfer t = {
			.tx_buf	= &st->spi_msg_nop,
			.rx_buf	= buf,
			.len = 2
		};

	st->spi_msg_nop = 0; /* NOP */

	return spi_sync_transfer(spi, &t, 1);
}

static int ad5592r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)
{
	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);

	st->spi_msg = cpu_to_be16(BIT(15) | (chan << 12) | value);

	return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
}

static int ad5592r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)
{
	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
	int ret;

	st->spi_msg = cpu_to_be16((AD5592R_REG_ADC_SEQ << 11) | BIT(chan));

	ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
	if (ret)
		return ret;

	/*
	 * Invalid data:
	 * See Figure 40. Single-Channel ADC Conversion Sequence
	 */
	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
	if (ret)
		return ret;

	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
	if (ret)
		return ret;

	*value = be16_to_cpu(st->spi_msg);

	return 0;
}

static int ad5592r_reg_write(struct ad5592r_state *st, u8 reg, u16 value)
{
	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);

	st->spi_msg = cpu_to_be16((reg << 11) | value);

	return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
}

static int ad5592r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value)
{
	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
	int ret;

	st->spi_msg = cpu_to_be16((AD5592R_REG_LDAC << 11) |
				   AD5592R_LDAC_READBACK_EN | (reg << 2));

	ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
	if (ret)
		return ret;

Annotation

Implementation Notes