am335x SPI spi_d0, spi_d1 out, in 模式设定

• AM335x SPI DO DI 的模式

    参考：   https://www.deyisupport.com/question_answer/dsp_arm/sitara_arm/f/25/t/138266.aspx

• 在 kernel 3.2.0 作代码修改

    //   vim drivers/spi/spi-omap2-mcspi.c
     654 static int omap2_mcspi_setup_transfer(struct spi_device *spi,
     655         struct spi_transfer *t)
     656 {
            // ... ...
            //   这里是设置 D0 为  MOSI   master input
           //                      D1  为  MISO   master output
     680 #if 0
     681     /* standard 4-wire master mode:  SCK, MOSI/out, MISO/in, nCS
     682      * REVISIT: this controller could support SPI_3WIRE mode.
     683      */
     684     l &= ~(OMAP2_MCSPI_CHCONF_IS|OMAP2_MCSPI_CHCONF_DPE1);
     685     l |= OMAP2_MCSPI_CHCONF_DPE0;
     686 #endif
     687 

            //  这里设置为   D0 为  MISO master output
           //                        D1 为  MOSI  master input
     688 #if 1
     689     /* standard 4-wire master mode:  SCK, MOSI/out, MISO/in, nCS
     690      * REVISIT: this controller could support SPI_3WIRE mode.
     691      */
     692     l &= ~(OMAP2_MCSPI_CHCONF_DPE0);
     693     l |= (OMAP2_MCSPI_CHCONF_IS | OMAP2_MCSPI_CHCONF_DPE1);
     694 #endif
            // ... ...

• 对应的 TRM 如下图：