Linux/DRA746: DRA746

Kevin Chen36

Part Number: DRA746

Tool/software: Linux

Hi Sir,

We get a trouble in configuring SPI MOSI pin to be MISO function and SPI MISO pin to be MOSI function. I want to configure the "spi2_d1.gpio7_15" pin to be MISO and the "spi2_d0.gpio7_16" to be MOSI. However, when I use below code in dts file, we find the "spi2_d1.gpio7_15" pin to be MOSI and the "spi2_d0.gpio7_16" to be MISO. Do you know how to make them tb what we want?

spi1_pins: pinmux_spi1_pins {
  pinctrl-single,pins = <
   //B2B_FST.LS_EN_3V3
   SPI1_CS2(PIN_OUTPUT | MUX_MODE14)    // spi1_cs2.gpio7_12
   //B2B_FST.SPI_WP_3V3
   SPI1_CS3(PIN_OUTPUT | MUX_MODE14)    // spi1_cs3.gpio7_13
   //B2B_FST.SPI.CLK_3V3
   SPI2_SCLK(PIN_INPUT | MUX_MODE0)    // spi2_sclk.gpio7_14
   //B2B_FST.SPI.MISO_IO1_3V3
   SPI2_D1(PIN_INPUT | MUX_MODE0)     // spi2_d1.gpio7_15
   //B2B_FST.SPI.MOSI_IO0_3V3
   SPI2_D0(PIN_INPUT | MUX_MODE0)     // spi2_d0.gpio7_16
   //B2B_FST.SPI.CS0_B_3V3
   SPI2_CS0(PIN_INPUT | MUX_MODE0)     // spi2_cs0.gpio7_17
  >;
};

Best Regards

Kevin

over 6 years ago

0 Yordan Kamenov over 6 years ago

TI__Mastermind 42515 points

Hi Kevin,

which version is your SDK/Kernel?

Regards,
Yordan

0 Kevin Chen36 over 6 years ago in reply to Yordan Kamenov

Intellectual 400 points

The SDK version is v3.02.00.03 and kernel version is 4.4.45.

Regards
Kevin

0 Yordan Kamenov over 6 years ago in reply to Kevin Chen36

TI__Mastermind 42515 points

Hi Kevin,

I have forwarded your question to Kernel experts.

Regards,
Yordan

0 Srirama Govindarajan over 6 years ago in reply to Yordan Kamenov

TI__Expert 8230 points

Hi
The actual pin mux is managed from the bootloader

Can you please clarify the intent behind the configuration change - is the wiring on the slave side inverse of what it needs to be? Have you checked the data manual to see if the reversal of functionality is possible on the same IO pin

0 Kevin Chen36 over 6 years ago in reply to Srirama Govindarajan

Intellectual 400 points

Hi Quote,

Thank you for your response. The "MCSPI_SYST" register describes we can configure the SPI2_D0 and SPI2_D1 input/output mode. Please refer to page 7154 of the "DRA75x_74x_SR1.1_NDA_TRM_vZ.pdf".

Best Regards

Kevin

0 Mariya Petkova over 6 years ago in reply to Kevin Chen36

TI__Expert 4885 points

Hi, Kevin Chen36,

Please, use the latest TRM, as there might be updates.

Regards,

Mariya

0 Kevin Chen36 over 6 years ago in reply to Mariya Petkova

Intellectual 400 points

Hi Sriram,
Because of HW is ready but there are below HW errors as below, we need to re-configure spi2_d1 and spi2_d0 direction by modifying dts file.

1. The default direction of spi2_d0 is MOSI but it connected to slave's outout.
2. The default direction of spi2_d1 is MIS0 but it connected to slave's input.

So we need to know how to configure spi2_d0 and spi2_d1 direction in dts file or providing others ways. Thank you!

Best regards
Kevin

0 Srirama Govindarajan over 6 years ago in reply to Kevin Chen36

TI__Expert 8230 points

Kevin
From what i understand , the ability to reconfigure spix_dx is available in test mode of operation and not during the functional state : i will confirm if the input/output mode can be reconfigured for the functional mode
If it is possible you then need to modify the pin mux configuration for IO direction change and add a hook for SW driver to configure spi2_d0/d1 pins accordingly

0 Stanislav Stilyanov over 6 years ago in reply to Srirama Govindarajan

TI__Genius 15120 points

Hi Kevin,

As Sriram mentioned - SYST is a 'system test' register - it is only functional in special 'test' mode.

You will rather need to set the MCSPI_CHxCONF (where x is CS number) register bits Input Select and Transmission enable.

Regards,

Stan

0 Kevin Chen36 over 6 years ago in reply to Stanislav Stilyanov

Intellectual 400 points

Hi Stan,
How do I configure the MCSPI_CHxCONF register in dts file?

Best Regrads
Kevin

0 Stanislav Stilyanov over 6 years ago in reply to Kevin Chen36

TI__Genius 15120 points

I think this function must be checked in the MCSPI driver for support. I'm sorry, I'm not aware how driver was implemented.

Regards,
Stan

0 Srirama Govindarajan over 6 years ago in reply to Stanislav Stilyanov

TI__Expert 8230 points

Hi
In case you are still looking for information

Adding this DT property to the mcspi node should help to swap lines:
"ti,pindir-d0-out-d1-in"

Documentation/devicetree/bindings/spi/omap-spi.txt

Hope this helps

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Linux/DRA746: DRA746