• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 98 subscribers
  • Views 406 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

changes in SPI kernel driver for RDK

Rakesh Modi
Expert 1680 points

Hi,

How can I change bit_per_word setting in SPI driver? Default driver uses 8-bit, I want to change it to 32-bit. Whenevr I tried to do that kernal could not boot properly and gives error in dma section. I did not understand the reason. Could anyone please help me, to resolve this?

Thank

Rakesh Modi

  • 0
    TI__Guru**** 170625 points

    Hi Rakesh,

    The McSPI peripheral module word length can be configured (per channel; 4 channels in DM816x device - 0,1,2,3) from 4 bits per word to 32 bits per word in register MCSPI_CHxCONF[11:7] WL (x = 0,1,2 or 3). When write 0x7 in [11:7] WL, word is 8 bits. When write 0x1F in [11:7] WL, word is 32 bits. See DM816x TRM, chapter 16 Serial Port Interface (SPI).

    The SPI driver user guide is below:

    http://processors.wiki.ti.com/index.php/TI81XX_PSP_McSPI_Driver_Guide

    I have no view to RDK, I work with EZSDK, but you can check if the below (which is valid for EZSDK) is also valid for RDK.

    The SPI driver in u-boot is located at u-boot-2010.06-psp04.04.00.01/drivers/spi/omap3_spi.c (.h) and we have the following regarding SPI word length programming:

    #define OMAP3_MCSPI_CHCONF_WL_MASK    (0x1f << 7)

    #define WORD_LEN    8

    /* wordlength */
        conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK;
        conf |= (WORD_LEN - 1) << 7;

    The SPI driver in linux kernel is located at linux-2.6.37-psp04.04.00.01/drivers/spi/omap2_mcspi.c and we have the following regarding SPI word length programming:

    #define OMAP2_MCSPI_CHCONF_WL_MASK    (0x1f << 7)

    /* wordlength */
        l &= ~OMAP2_MCSPI_CHCONF_WL_MASK;
        l |= (word_len - 1) << 7;

    Regards,

    Pavel