drivers/comedi/drivers/dac02.c

Source file repositories/reference/linux-study-clean/drivers/comedi/drivers/dac02.c

File Facts

System
Linux kernel
Corpus path
drivers/comedi/drivers/dac02.c
Extension
.c
Size
3745 bytes
Lines
138
Domain
Driver Families
Bucket
drivers/comedi
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+
/*
 * dac02.c
 * Comedi driver for DAC02 compatible boards
 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
 *
 * Based on the poc driver
 * Copyright (C) 2000 Frank Mori Hess <fmhess@users.sourceforge.net>
 * Copyright (C) 2001 David A. Schleef <ds@schleef.org>
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
 */

/*
 * Driver: dac02
 * Description: Comedi driver for DAC02 compatible boards
 * Devices: [Keithley Metrabyte] DAC-02 (dac02)
 * Author: H Hartley Sweeten <hsweeten@visionengravers.com>
 * Updated: Tue, 11 Mar 2014 11:27:19 -0700
 * Status: unknown
 *
 * Configuration options:
 *	[0] - I/O port base
 */

#include <linux/module.h>
#include <linux/comedi/comedidev.h>

/*
 * The output range is selected by jumpering pins on the I/O connector.
 *
 *	    Range      Chan #   Jumper pins        Output
 *	-------------  ------  -------------  -----------------
 *	   0 to 5V       0        21 to 22      24
 *	                 1        15 to 16      18
 *	   0 to 10V      0        20 to 22      24
 *	                 1        14 to 16      18
 *	    +/-5V        0        21 to 22      23
 *	                 1        15 to 16      17
 *	    +/-10V       0        20 to 22      23
 *	                 1        14 to 16      17
 *	  4 to 20mA      0        21 to 22      25
 *	                 1        15 to 16      19
 *	AC reference     0      In on pin 22    24 (2-quadrant)
 *	                        In on pin 22    23 (4-quadrant)
 *	                 1      In on pin 16    18 (2-quadrant)
 *	                        In on pin 16    17 (4-quadrant)
 */
static const struct comedi_lrange das02_ao_ranges = {
	6, {
		UNI_RANGE(5),
		UNI_RANGE(10),
		BIP_RANGE(5),
		BIP_RANGE(10),
		RANGE_mA(4, 20),
		RANGE_ext(0, 1)
	}
};

/*
 * Register I/O map
 */
#define DAC02_AO_LSB(x)		(0x00 + ((x) * 2))
#define DAC02_AO_MSB(x)		(0x01 + ((x) * 2))

static int dac02_ao_insn_write(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       struct comedi_insn *insn,
			       unsigned int *data)
{
	unsigned int chan = CR_CHAN(insn->chanspec);
	unsigned int range = CR_RANGE(insn->chanspec);
	unsigned int val;
	int i;

	for (i = 0; i < insn->n; i++) {
		val = data[i];

		s->readback[chan] = val;

		/*
		 * Unipolar outputs are true binary encoding.
		 * Bipolar outputs are complementary offset binary
		 * (that is, 0 = +full scale, maxdata = -full scale).
		 */
		if (comedi_range_is_bipolar(s, range))
			val = s->maxdata - val;

		/*

Annotation

Implementation Notes