2 files changed, 39 insertions, 0 deletions

diff --git a/arch/arm/mach-davinci/include/mach/spi.h b/arch/arm/mach-davinci/include/mach/spi.h
index 1f8b7866bea..38f4da5ca13 100644
--- a/arch/arm/mach-davinci/include/mach/spi.h
+++ b/arch/arm/mach-davinci/include/mach/spi.h
@@ -26,6 +26,20 @@ enum {
         SPI_VERSION_2, /* For DA8xx */
 };
 
+/**
+ * davinci_spi_platform_data - Platform data for SPI master device on DaVinci
+ *
+ * @version:    version of the SPI IP. Different DaVinci devices have slightly
+ *              varying versions of the same IP.
+ * @num_chipselect: number of chipselects supported by this SPI master
+ * @intr_line:  interrupt line used to connect the SPI IP to the ARM interrupt
+ *              controller withn the SoC. Possible values are 0 and 1.
+ * @chip_sel:   list of GPIOs which can act as chip-selects for the SPI.
+ *              SPI_INTERN_CS denotes internal SPI chip-select. Not necessary
+ *              to populate if all chip-selects are internal.
+ * @cshold_bug: set this to true if the SPI controller on your chip requires
+ *              a write to CSHOLD bit in between transfers (like in DM355).
+ */
 struct davinci_spi_platform_data {
         u8      version;
         u8      num_chipselect;
@@ -34,6 +48,24 @@ struct davinci_spi_platform_data {
         bool    cshold_bug;
 };
 
+/**
+ * davinci_spi_config - Per-chip-select configuration for SPI slave devices
+ *
+ * @wdelay:     amount of delay between transmissions. Measured in number of
+ *              SPI module clocks.
+ * @odd_parity: polarity of parity flag at the end of transmit data stream.
+ *              0 - odd parity, 1 - even parity.
+ * @parity_enable: enable transmission of parity at end of each transmit
+ *              data stream.
+ * @io_type:    type of IO transfer. Choose between polled, interrupt and DMA.
+ * @timer_disable: disable chip-select timers (setup and hold)
+ * @c2tdelay:   chip-select setup time. Measured in number of SPI module clocks.
+ * @t2cdelay:   chip-select hold time. Measured in number of SPI module clocks.
+ * @t2edelay:   transmit data finished to SPI ENAn pin inactive time. Measured
+ *              in number of SPI clocks.
+ * @c2edelay:   chip-select active to SPI ENAn signal active time. Measured in
+ *              number of SPI clocks.
+ */
 struct davinci_spi_config {
         u8      wdelay;
         u8      odd_parity;
diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c
index 2ec5fd2f2e7..f40f1be1528 100644
--- a/drivers/spi/davinci_spi.c
+++ b/drivers/spi/davinci_spi.c
@@ -787,6 +787,13 @@ rx_dma_failed:
 /**
  * davinci_spi_probe - probe function for SPI Master Controller
  * @pdev: platform_device structure which contains plateform specific data
+ *
+ * According to Linux Device Model this function will be invoked by Linux
+ * with platform_device struct which contains the device specific info.
+ * This function will map the SPI controller's memory, register IRQ,
+ * Reset SPI controller and setting its registers to default value.
+ * It will invoke spi_bitbang_start to create work queue so that client driver
+ * can register transfer method to work queue.
  */
 static int davinci_spi_probe(struct platform_device *pdev)
 {