Fix code to set SPI frequency/clock
@@ -237,16 +237,19 @@ mraa_spi_frequency(mraa_spi_context dev, int hz)
}
int speed = 0;
- dev->clock = hz;
- if (ioctl(dev->devfd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) != -1) {
- if (speed < hz) {
- // We wanted to never go higher than SPI_IOC_RD_MAX_SPEED_HZ but it
- // seems a bunch of drivers don't have this set to the actual max
- // so we only complain about it
- // dev->clock = speed;
- syslog(LOG_NOTICE, "spi: Selected speed (%d Hz) is higher than the kernel max allowed speed (%lu Hz)", hz, SPI_IOC_RD_MAX_SPEED_HZ);
+ if (ioctl(dev->devfd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) == 0) {
+ dev->clock = speed; // if setting the clock fails, at least we
+ // will be able to known what the real
+ // clock of the device is
}
+ else
+ syslog(LOG_NOTICE, "spi: unable to read SPI clock. Error %d %s", errno, strerror(errno));
+
+ if (ioctl(dev->devfd, SPI_IOC_WR_MAX_SPEED_HZ, &hz) != 0) {
+ syslog(LOG_ERR, "spi: failed to set SPI clock. Original value remains (%d). Error %d %s", speed, errno, strerror(errno));
+ return MRAA_ERROR_INVALID_RESOURCE;
}
+ dev->clock = hz; // store the actual clock now that we succeeded changing it
return MRAA_SUCCESS;
}
