drivers/video/s5p-spi.c

   1 #include <asm/arch/gpio.h>
   2 #include "s5p-spi.h"
   3
   4
   5 static void cs_low(struct spi_platform_data *spi)
   6 {
   7         gpio_set_value(spi->cs_bank, spi->cs_num, 0);
   8 }
   9
  10 static void cs_high(struct spi_platform_data *spi)
  11 {
  12         gpio_set_value(spi->cs_bank, spi->cs_num, 1);
  13 }
  14
  15 static void clk_low(struct spi_platform_data *spi)
  16 {
  17         gpio_set_value(spi->clk_bank, spi->clk_num, 0);
  18 }
  19
  20 static void clk_high(struct spi_platform_data *spi)
  21 {
  22         gpio_set_value(spi->clk_bank, spi->clk_num, 1);
  23 }
  24
  25 static void si_low(struct spi_platform_data *spi)
  26 {
  27         gpio_set_value(spi->si_bank, spi->si_num, 0);
  28 }
  29
  30 static void si_high(struct spi_platform_data *spi)
  31 {
  32         gpio_set_value(spi->si_bank, spi->si_num, 1);
  33 }
  34
  35 static char so_read(struct spi_platform_data *spi)
  36 {
  37         return gpio_get_value(spi->so_bank, spi->so_num);
  38 }
  39
  40 void spi_write_byte(struct spi_platform_data *spi, unsigned char address, unsigned char command)
  41 {
  42         int     j;
  43         unsigned short data;
  44         unsigned char DELAY = 1;
  45
  46         data = (address << 8) + command;
  47
  48         cs_high(spi);
  49         si_high(spi);
  50         clk_high(spi);
  51         udelay(DELAY);
  52
  53         cs_low(spi);
  54         udelay(DELAY);
  55
  56         for (j = PACKET_LEN; j >= 0; j--)
  57         {
  58                 clk_low(spi);
  59
  60                 /* data high or low */
  61                 if ((data >> j) & 0x1)
  62                         si_high(spi);
  63                 else
  64                         si_low(spi);
  65
  66                 udelay(DELAY);
  67
  68                 clk_high(spi);
  69                 udelay(DELAY);
  70         }
  71
  72         cs_high(spi);
  73         udelay(DELAY);
  74 }
  75
  76 #ifdef UNUSED_FUNCTIONS
  77 unsigned char spi_read_byte(struct spi_platform_data *spi, unsigned char select, unsigned char address)
  78 {
  79         int     j;
  80         static unsigned int first = 1;
  81         unsigned char DELAY = 1;
  82         unsigned short data = 0;
  83         char command = 0;
  84
  85         data = (select << 8) + address;
  86
  87         cs_high(spi);
  88         si_high(spi);
  89         clk_high(spi);
  90         udelay(DELAY);
  91
  92         clk_low(spi);
  93         udelay(DELAY);
  94
  95         for (j = PACKET_LEN + 8; j >= 0; j--)
  96         {
  97
  98                 if (j > 7) {
  99                         clk_low(spi);
 100
 101                         /* data high or low */
 102                         if ((data >> (j - 8)) & 0x1)
 103                                 si_high(spi);
 104                         else
 105                                 si_low(spi);
 106
 107                         udelay(DELAY);
 108                         clk_high(spi);
 109                 } else {
 110                         if (first) {
 111                                 gpio_cfg_pin(spi->so_bank, spi->so_num, GPIO_INPUT);
 112                                 first = 0;
 113                         }
 114
 115                         clk_low(spi);
 116
 117                         if (so_read(spi) & 0x1)
 118                                 command |= 1 << j;
 119                         else
 120                                 command |= 0 << j;
 121
 122                         udelay(DELAY);
 123                         clk_high(spi);
 124                 }
 125
 126                 udelay(DELAY);
 127         }
 128
 129         cs_high(spi);
 130         udelay(DELAY);
 131
 132         gpio_cfg_pin(spi->so_bank, spi->so_num, GPIO_OUTPUT);
 133
 134         return command;
 135 }
 136 #endif