Linux SPI driver--spidev deive (v)

1. Defining Board Devices

   1:  struct spi_board_info {

   2:  /    * The device name and module name is coupled, like platform_bus;

   3:       * "Modalias" is normally the driver name.

   4:       *

   5:       * Platform_data goes to Spi_device.dev.platform_data,

   6:       * Controller_data goes to Spi_device.controller_data,

   7:       * IRQ is copied too

   8:       * /

   9:      char        modalias[spi_name_size];

  Ten:      constvoid    *platform_data;

One   :      void        *controller_data;

int   :              IRQ;

  :  

*   /      * Slower signaling on noisy or low voltage boards * /

  :      u32        max_speed_hz;

  :  

  :  

*   /      * bus_num is board specific and matches the bus_num of some

* Spi_master   that  would     probably be registered later.

*   :       *

  £ º       * Chip_select reflects how the this chip was wired to that master;

  :       * It's less than num_chipselect.

At   :       * /

  :      U16        Bus_num;

  :      U16        Chip_select;

  £ º  

*   /      * mode becomes spi_device.mode, and is essential for chips

  :       * Where the default of Spi_cs_high = 0 is wrong.

  :       * /

  :      u8        mode;

  £ º  

*   /      * Need additional Spi_device chip config data here.

  :       * Avoid stuff protocol drivers can set; but include stuff

* needed to     behave without being bound to a driver:   

*-quirks like clock rate mattering if not  selected   

     *   /  

   1:  /* Add by Xuyonghong for test * /

   2:  struct spi_board_info jz_spi0_board_info[]  = {

   3:      {

   4:          . Modalias               =  "Spidev",

   5:          . Mode                     =  spi_mode_3,

   6:          . max_speed_hz           =  1000000,

   7:          . Controller_data        =  (void *) GPIO_PB (2),

   8:          . Bus_num                =  0,

   9:          . Chip_select            =  0,

  Ten:      },

One   :  };

  :  int jz_spi0_devs_size = array_size (Jz_spi0_board_info);

   1:  int __init

   2:  spi_register_board_info (structconst *info, unsigned n)

   3:  {

   4:      struct boardinfo *bi;

   5:      int i;

   6:  

   7:      sizeof(*BI), Gfp_kernel);

   8:      if (!BI)

   9:          return -enomem;

  Ten:  

One   :  for     (i = 0; i < n; i++, bi++, info++) {

  :          struct spi_master *master;

  :  

  :          sizeof(*info));

  :          mutex_lock (&board_lock);

  :          list_add_tail (&bi->list, &board_list);

  17:          

if master            first registers, then performs a spi_match_master_to_boardinfo match,   

  19:              

  :          * /

  :          list_for_each_entry (master, &spi_master_list, list)

  :              spi_match_master_to_boardinfo (master, &bi->board_info);

At   :          mutex_unlock (&board_lock);

  :      }

  :  

  :      return 0;

  :  }

   1:  spi_register_board_info (Jz_spi0_board_info, jz_spi0_devs_size);

Summarize:

1. List_add_tail (&bi->list, &board_list); Speaking board added in Board_list

2. When Master is already registered, the SPI device is created via Spi_match_master_to_boardinfo and Spi_new_device.

Linux SPI driver--spidev deive (v)