mirror of https://github.com/Desuuuu/klipper.git
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
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// Communicating with an SPI device via linux spidev
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//
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// Copyright (C) 2017 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include <fcntl.h> // open
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#include <stdio.h> // snprintf
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#include <unistd.h> // write
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#include "command.h" // DECL_COMMAND
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#include "internal.h" // report_errno
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#include "sched.h" // shutdown
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struct spi_s {
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uint32_t bus, dev;
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int fd;
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};
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static struct spi_s devices[16];
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static int devices_count;
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static int
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spi_open(uint32_t bus, uint32_t dev)
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{
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// Find existing device (if already opened)
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int i;
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for (i=0; i<devices_count; i++)
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if (devices[i].bus == bus && devices[i].dev == dev)
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return devices[i].fd;
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// Setup new SPI device
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if (devices_count >= ARRAY_SIZE(devices))
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shutdown("Too many spi devices");
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char fname[256];
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snprintf(fname, sizeof(fname), "/dev/spidev%d.%d", bus, dev);
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int fd = open(fname, O_RDWR|O_CLOEXEC);
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if (fd < 0) {
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report_errno("open spi", fd);
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shutdown("Unable to open spi device");
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}
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int ret = set_non_blocking(fd);
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if (ret < 0)
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shutdown("Unable to set non-blocking on spi device");
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devices[devices_count].bus = bus;
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devices[devices_count].dev = dev;
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devices[devices_count].fd = fd;
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return fd;
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}
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static void
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spi_write(int fd, char *data, int len)
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{
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int ret = write(fd, data, len);
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if (ret < 0) {
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report_errno("write spi", ret);
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shutdown("Unable to write to spi");
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}
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}
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void
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command_send_spi(uint32_t *args)
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{
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int fd = spi_open(args[0], args[1]);
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uint8_t len = args[2];
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char *msg = (void*)(size_t)args[3];
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spi_write(fd, msg, len);
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}
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DECL_COMMAND(command_send_spi, "send_spi bus=%u dev=%u msg=%*s");
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