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Utility: Adding tool to control Attenuator (ZX76-31R5-SP+)

- Uses sysfs GPIO to control the attenuator chip
- Attenuation setable in 0.5 dB steps, maximum is 31.5 dB
- Attenuators are referenced by their ID (1-4)
master
Philipp Maier 5 years ago
commit
7c46bd12f6
  1. 13
      util/Makefile
  2. 143
      util/gpio.c
  3. 43
      util/gpio.h
  4. 175
      util/main.c

13
util/Makefile

@ -0,0 +1,13 @@
all: main.o gpio.o
gcc -Wall ./*.o -losmocore -ltalloc -o attctrl -O3
main.o: main.c
gcc -Wall -c main.c
gpio.o: gpio.c
gcc -Wall -c gpio.c
clean:
rm -f ./*.o
rm -f ./attctrl

143
util/gpio.c

@ -0,0 +1,143 @@
/* GPIO handler routines */
/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Philipp Maier
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include "gpio.h"
#define SYSFS_EXPORT "/sys/class/gpio/export"
#define SYSFS_UNEXPORT "/sys/class/gpio/unexport"
#define SYSFS_DIRECTION "/sys/class/gpio/gpio%d/direction"
#define SYSFS_VALUE "/sys/class/gpio/gpio%d/value"
/* Open sysfs endpoints and initalize GPIOs */
struct gpio_descr *gpio_open(void *ctx, unsigned int *gpios,
unsigned int gpios_len)
{
int i;
char buf[255];
FILE *fd_export = NULL;
FILE *fd_direction[MAX_GPIOS];
FILE *fd_value[MAX_GPIOS];
struct gpio_descr *gd;
OSMO_ASSERT(gpios);
OSMO_ASSERT(gpios_len <= MAX_GPIOS);
/* Export requested GPIOs to userspace */
fd_export = fopen(SYSFS_EXPORT, "w");
if (!fd_export) {
printf("Error: Could not open: %s\n", SYSFS_EXPORT);
return NULL;
} else {
for (i = 0; i < gpios_len; i++) {
sprintf(buf, "%d", gpios[i]);
rewind(fd_export);
fputs(buf, fd_export);
}
fclose(fd_export);
fd_export = NULL;
}
/* Open GPIO file descriptors */
for (i = 0; i < gpios_len; i++) {
sprintf(buf, SYSFS_DIRECTION, gpios[i]);
fd_direction[i] = fopen(buf, "w");
if (!fd_direction[i]) {
printf("Error: Could not open: %s\n", buf);
return NULL;
}
sprintf(buf, SYSFS_VALUE, gpios[i]);
fd_value[i] = fopen(buf, "w");
if (!fd_value[i]) {
printf("Error: Could not open: %s\n", buf);
return NULL;
}
}
/* Configure GPIOs as outputs */
for (i = 0; i < gpios_len; i++) {
rewind(fd_direction[i]);
fputs("out", fd_direction[i]);
fflush(fd_direction[i]);
}
/* Generate descriptor struct */
gd = talloc_zero(ctx, struct gpio_descr);
memcpy(gd->gpios, gpios, sizeof(gd->gpios));
gd->gpios_len = gpios_len;
memcpy(gd->fd_direction, fd_direction, sizeof(gd->fd_direction));
memcpy(gd->fd_value, fd_value, sizeof(gd->fd_value));
return gd;
}
/* Close sysfs endpoints and unintialize GPIOs */
void gpio_close(struct gpio_descr *gd)
{
int i;
char buf[255];
FILE *fd_unexport = NULL;
OSMO_ASSERT(gd);
/* Close GPIOs file descriptors */
for (i = 0; i < gd->gpios_len; i++) {
if (gd->fd_direction[i])
fclose(gd->fd_direction[i]);
if (gd->fd_value[i])
fclose(gd->fd_value[i]);
}
/* Remove requested GPIOs from userspace */
fd_unexport = fopen(SYSFS_UNEXPORT, "w");
if (fd_unexport) {
for (i = 0; i < gd->gpios_len; i++) {
sprintf(buf, "%d", gd->gpios[i]);
rewind(fd_unexport);
fputs(buf, fd_unexport);
}
fclose(fd_unexport);
}
/* Free descriptor struct */
talloc_free(gd);
}
/* Set GPIO pin status */
void gpio_set(struct gpio_descr *gd, unsigned int gpio, unsigned int state)
{
OSMO_ASSERT(gd);
OSMO_ASSERT(gpio < gd->gpios_len);
rewind(gd->fd_value[gpio]);
if (state)
fputs("1", gd->fd_value[gpio]);
else
fputs("0", gd->fd_value[gpio]);
fflush(gd->fd_value[gpio]);
}

43
util/gpio.h

@ -0,0 +1,43 @@
/* GPIO handler routines */
/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Philipp Maier
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#define MAX_GPIOS 16
/* Struct holding the GPIO file descriptors and
meta information about the GPIO itsself */
struct gpio_descr {
unsigned int gpios[MAX_GPIOS];
unsigned int gpios_len;
FILE *fd_direction[MAX_GPIOS];
FILE *fd_value[MAX_GPIOS];
};
/* Open sysfs endpoints and initalize GPIOs */
struct gpio_descr *gpio_open(void *ctx, unsigned int *gpios,
unsigned int gpios_len);
/* Close sysfs endpoints and unintialize GPIOs */
void gpio_close(struct gpio_descr *gd);
/* Set GPIO pin status */
void gpio_set(struct gpio_descr *gd, unsigned int gpio, unsigned int state);

175
util/main.c

@ -0,0 +1,175 @@
/* Tool to control ZX76-31R5-SP-S+ digital attenuators on LTHW Main unit */
/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Philipp Maier
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include "gpio.h"
/* GPIO pin assignment */
#define GPIO_LE_1 13
#define GPIO_LE_2 7
#define GPIO_LE_3 5
#define GPIO_LE_4 11
#define GPIO_DATA 15
#define GPIO_CLK 17
/* Internal GPIO alias */
#define LE_1 0
#define LE_2 1
#define LE_3 2
#define LE_4 3
#define DATA 4
#define CLK 5
/* ZX76-31R5-SP-S+ properties */
#define DB_MAX 31.5
/* Generate a clock or latch enable pulse */
static inline void gpio_pulse(struct gpio_descr *gd, unsigned int gpio)
{
gpio_set(gd, gpio, 1);
gpio_set(gd, gpio, 0);
}
/* Write control word to Attenuator */
void att_write(struct gpio_descr *gd, uint8_t cw, unsigned int le)
{
int i;
unsigned int bit;
/* Write control word (val) to Attenuator */
for (i = 5; i >= 0; i--) {
bit = ((cw >> i) & 1);
gpio_set(gd, DATA, bit);
gpio_pulse(gd, CLK);
}
/* Generate latch enable pulse */
gpio_pulse(gd, le);
}
/* Initalize attenuators */
struct gpio_descr *att_init(void)
{
unsigned int gpios[6];
struct gpio_descr *gd;
/* GPIO pin mapping */
gpios[LE_1] = GPIO_LE_1;
gpios[LE_2] = GPIO_LE_2;
gpios[LE_3] = GPIO_LE_3;
gpios[LE_4] = GPIO_LE_4;
gpios[DATA] = GPIO_DATA;
gpios[CLK] = GPIO_CLK;
/* Open GPIO */
gd = gpio_open(NULL, gpios, 6);
if (!gd) {
printf("Error: Unable to open GPIO\n");
exit(1);
}
/* Initalize GPIOs to low level */
gpio_set(gd, LE_1, 0);
gpio_set(gd, LE_2, 0);
gpio_set(gd, LE_3, 0);
gpio_set(gd, LE_4, 0);
gpio_set(gd, DATA, 0);
gpio_set(gd, CLK, 0);
return gd;
}
/* Set attenuator value */
void att_set(struct gpio_descr *gd, double val, unsigned int le)
{
uint8_t cw;
if (val > DB_MAX || val < 0) {
printf("Error: Invalid attenuation value!\n");
return;
}
printf("Setting attenuator #%d to value %.1lf...\n", le + 1, val);
cw = (uint8_t) (val * 2);
att_write(gd, cw, le);
}
/* Print online help */
void print_help(char *progname)
{
printf("Usage: %s -i ID -a ATT\n", progname);
printf("Attenuation (ATT) in 0.5db steps, range 0-31.5\n");
printf("\n");
exit(0);
}
int main(int argc, char *argv[])
{
struct gpio_descr *gd;
int option;
double getopt_att = -1;
int getopt_id = -1;
/* Parse options */
while ((option = getopt(argc, argv, "hi:a:")) != -1) {
switch (option) {
case 'h':
print_help(basename(argv[0]));
break;
case 'a':
getopt_att = atof(optarg);
break;
case 'i':
getopt_id = atoi(optarg) - 1;
break;
}
}
/* Check options */
if (getopt_att < 0) {
printf("Error: No attenuation value specified!\n");
exit(1);
}
if (getopt_id < 0) {
printf("Error: No attenuator id specified!\n");
exit(1);
}
if (getopt_id > 3) {
printf("Error: Invalid attenuator id specified!\n");
exit(1);
}
/* Set attenuation */
gd = att_init();
att_set(gd, getopt_att, getopt_id);
gpio_close(gd);
return 0;
}
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