Raspberries/mraa
Private
Public Access
2
0
Fork 0
Code Activity

Fix code to set SPI frequency/clock

Browse Source 
Signed-off-by: Jandrioli <joao_andrioli@hotmail.com>
This commit is contained in:
Jandrioli
2020-06-22 14:14:10 -04:00
committed by Propanu
parent 710106d99f
commit d74b0d8a73
1 changed files with 12 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/spi/spi.c
View File

@@ -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;
}