spi: loopback-test: provide loop_req option.

Provide a module parameter to request internal loop by the SPI master
controller.
This should make loop testing easier without extra HW modification.

For test automation a logic analyzer is recommended for host
controller-independent verification.
An example test rig configuration and procedure:
  i.MX6S RIoRBoard           Logic Analyzer
  -----------------------------------------
  (J13  4) GND ------------- GND
  (J13  6) CSPI3-CLK ------> PIN 3
  (J13  8) CSPI3-MOSI <----- PIN 2
     ^ - internal loop configured by SPI_LOOP
     |   or can be user external jamper.
  (J13 10) CSPI3-MISO -----> PIN 1

grab some data and decode it:
sigrok-cli -d fx2lafw --time 160000 --config samplerate=10m  \
  --channels 0-2 -o dump.sr
sigrok-cli -i dump.sr -P spi:mosi=1:clk=2 > result_for_regression_tests

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Oleksij Rempel 2017-07-14 11:42:46 +02:00 committed by Mark Brown
parent 5771a8c088
commit f12a616e0c

View File

@ -51,6 +51,12 @@ MODULE_PARM_DESC(loopback,
"is checked to match tx_buf after the spi_message " \ "is checked to match tx_buf after the spi_message " \
"is executed"); "is executed");
int loop_req;
module_param(loop_req, int, 0);
MODULE_PARM_DESC(loop_req,
"if set controller will be asked to enable test loop mode. " \
"If controller supported it, MISO and MOSI will be connected");
/* run only a specific test */ /* run only a specific test */
int run_only_test = -1; int run_only_test = -1;
module_param(run_only_test, int, 0); module_param(run_only_test, int, 0);
@ -313,6 +319,16 @@ static int spi_loopback_test_probe(struct spi_device *spi)
{ {
int ret; int ret;
if (loop_req) {
spi->mode = SPI_LOOP | spi->mode;
ret = spi_setup(spi);
if (ret) {
dev_err(&spi->dev, "SPI setup with SPI_LOOP failed (%d)\n",
ret);
return ret;
}
}
dev_info(&spi->dev, "Executing spi-loopback-tests\n"); dev_info(&spi->dev, "Executing spi-loopback-tests\n");
ret = spi_test_run_tests(spi, spi_tests); ret = spi_test_run_tests(spi, spi_tests);