sspscreen.c

pxa ssp直接写屏源代码,using ssp interface to write lcd driver code

#include  <linux/module.h>
#include <linux/autoconf.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/sysctl.h>
#include <linux/interrupt.h>

#include <asm/uaccess.h>

#include <asm/arch/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/ssp.h>
#include <asm/arch/irqs.h>
#include <asm/errno.h>

#include "sspscreen.h"

#define DEVICE_NAME "screen"

#define SCREEN_BAUD      (0x001 << 8)
#define DSS_9         8
#define FRF_SPI         0
#define SSE_ENABLED      (1 << 7)
#define SPO            (1 << 3)
#define SPH            (1 << 4)

//**********************************************************************
// NSSP lines and GPIOs

static int gNSSPClk = 81;   //NSSP_CLOCK
static int gNSSPCS = 82;    //NSSP_FRAME
static int gNSSPData = 83;  //NSSP_TXD MOSI
static int gGPIOReset = 84; //NSSP_RXD MISO

struct ssp_dev gSpiDevice;

//**********************************************************************
// DELAY

static void screen_delay(int n)
{
   int time_to_stop = get_jiffies_64() + n;
   int time_now;

   do
   {
      time_now = get_jiffies_64();
      cpu_relax();
      //printk("n: %d now: %d stop: %d\n", n, time_now, time_to_stop);
   }while(time_now < time_to_stop);
}

//**********************************************************************
// SET/CLEAR

static void set_gpio(int gpio)
{
   GPSR(gpio) = GPIO_bit(gpio);
}

static void clear_gpio(int gpio)
{
   GPCR(gpio) = GPIO_bit(gpio);
}


//**********************************************************************
// SEND BIT/DATA/COMMAND

void send_cmd(unsigned char b)
{
   int value;
   u32 readOut;
   readOut=0;
   value = b;
   // Write data
   ssp_write_word(&gSpiDevice, value);
   // Read to keep SPI happy!
   ssp_read_word(&gSpiDevice, &readOut);
}

void send_data(unsigned char b)
{
   int value;
   u32 readOut;
   readOut=0;
   value = b | 0x100;
   // Write data
   ssp_write_word(&gSpiDevice, value);
   // Read to keep SPI happy!
   ssp_read_word(&gSpiDevice,&readOut);
}

//**********************************************************************
// PUT PIXEL

void put_pixel(unsigned char color, unsigned char x, unsigned char y)
{
  send_cmd(PASET);    // page start/end ram
  send_data(x);// for some reason starts at 2
  send_data(x + 1);
  send_cmd(CASET);    // column start/end ram
  send_data(y);      // for some reason starts at 2
  send_data(y + 1);
  send_cmd(RAMWR);    // write something
  send_data(color);
}

//**********************************************************************
// FILE OPERATIONS

struct file_operations screen_fops =
{
    owner:      THIS_MODULE,
//    ioctl:      whatever,
//    open:       jogwheel_open,
//    release:    jogwheel_release,
//    read:       jogwheel_read,
};

//**********************************************************************
// INIT

static int __init screen_init( void )
{
    int rc;
    int i;
    int speed = SCREEN_BAUD;
    int mode = DSS_9 | FRF_SPI | SSE_ENABLED;
    int flags = SPO | SPH;
    int result=0;
   printk("screen: init called\n");

    // register our device with Linux

    if (( rc = register_chrdev( SCREEN_MAJOR, DEVICE_NAME, &screen_fops )) < 0 )
    {
        printk( KERN_WARNING "screen: register_chrdev failed for major %d\n", SCREEN_MAJOR );
        return rc;
    }

   printk("screen: init GPIO pins\n");

   // Pin functions and directions
   pxa_gpio_mode( gNSSPData  | GPIO_ALT_FN_1_OUT );
   pxa_gpio_mode( gNSSPClk   | GPIO_ALT_FN_1_OUT );
   pxa_gpio_mode( gNSSPCS    | GPIO_ALT_FN_1_OUT );
   pxa_gpio_mode( gGPIOReset | GPIO_OUT );

   // Setup GPIO levels
   set_gpio(gGPIOReset);
   
   printk("screen: init NSSP\n");
   result=ssp_init(&gSpiDevice, 2,flags);
    if (result)
    {
      printk("ssp_init() failed!\n");
    }
   printk("ssp_init() success!%d\n",result);

   /* configure NSSP port parameters */
   ssp_config(&gSpiDevice, mode, flags, 0, speed);

   ssp_enable(&gSpiDevice);

   printk("screen: display reset\n");

   // Reset the display
   clear_gpio(gGPIOReset);
   screen_delay(10);
   set_gpio(gGPIOReset);
   screen_delay(10);

   printk("screen: display reset : control\n");
   // display control
   send_cmd(DISCTL);
   printk("screen: display reset : send_cmd(DISCTL)\n");
   send_data(0x03);
   printk("screen: display reset : d1\n");
   send_data(0x20);
   printk("screen: display reset : d2\n");
   send_data(0x0C);
    //send_data(0x00); // EH?
   printk("screen: display reset : comscn\n");
   // comscn
   send_cmd(COMSCN);
   send_data(0x01);
   printk("screen: display reset : oscon\n");
   // oscon
   send_cmd(OSCON);

   // sleep out
   printk("screen: sleep out\n");
   send_cmd(SLPOUT);
   screen_delay(10);

   // electronic volume, this is kinda contrast/brightness
   //  this might be different for individual LCDs
   send_cmd(VOLCTR);
   send_data(0x05);
   send_data(0x01);
   send_cmd(VOLDOWN);
   send_cmd(VOLDOWN);

   send_cmd(TMPGRD);
   send_data(0);
   send_data(0);
   send_data(0);
   send_data(0);
   send_data(0);

   // power ctrl
   //everything on, no external reference resistors
   send_cmd(PWRCTR);
   send_data(0x0f);
   screen_delay(10);

   //send_cmd(PTLOUT);

   //send_cmd(RMWOUT);

   // Scroll area
   //send_cmd(ASCSET);
   //send_data(0x00);
   //send_data(0x00);
   //send_data(0x00);
   //send_data(0x03); // Whole screen

   //send_cmd(SCSTART);
   //send_data(0x00);

   // display mode
   send_cmd(DISINV);

   // datctl
   send_cmd(DATCTL);
   send_data(0x00);
   send_data(0x00);
   send_data(0x01);

   printk("screen: color LUT\n");

   // setup color lookup table
   send_cmd(RGBSET8);
    // color table
    //RED
    send_data(0);
    send_data(2);
    send_data(4);
    send_data(6);
    send_data(8);
    send_data(10);
    send_data(12);
    send_data(15);
    // GREEN
    send_data(0);
    send_data(2);
    send_data(4);
    send_data(6);
    send_data(8);
    send_data(10);
    send_data(12);
    send_data(15);
    //BLUE
    send_data(0);
    send_data(4);
    send_data(9);
    send_data(15);

    // nop
   send_cmd(NOP);

   // display on
   screen_delay(100);
   printk("screen: display on\n");
   send_cmd(DISON);
   screen_delay(10);

   // this loop adjusts the contrast, change the number of iterations to get
   // desired contrast.  this might be different for individual LCDs

   printk("screen: contrast loop\n");
   for (i = 0; i < 50; i++)
   {
      send_cmd(VOLUP);
   }

   // page start/end ram
   send_cmd(PASET);
   // for some reason starts at 2
   send_data(0x00);
   send_data(0x83);

   // column start/end ram
   send_cmd(CASET);
   send_data(0x00);
   send_data(0x83);

   // write some stuff (background)
   send_cmd(RAMWR);
   for (i = 0; i < 17424; i++)
   {
      if(i % 200 == 0)
        printk("screen: background: %d\r", i);

      send_data(i % 0x100);

      //if(i == 200)
      //  send_data(0xE0);  // 1C is green E0 is red 03 is blue
      //else if(i % 3 == 1)
      //   send_data(0x1C);  // 1C is green E0 is red 03 is blue
      //else
      //   send_data(0x03);  // 1C is green E0 is red 03 is blue
   }
   printk("screen: background: %d\n", i);

   // draw a multi-colored square in the center of screen
   int x, y, c;
   for (i = 0; i < 4096; i++)
   {
      if(i % 50 == 0)
        printk("screen: square: %d\r", i);

      x = (i % 64) + 32;
      y = (i / 64) + 32;

      if(x <= 63 && y <= 63)
        c = 0xE0;
      else if(x > 63 && y <= 63)
        c = 0x1C;
      else if(x <= 63 && y > 63)
        c = 0x03;
      else
        c = 0xE3;

      put_pixel(c, x, y);
   }
   printk("screen: square: %d\n", i);
   return 0;
}

//**********************************************************************
// EXIT

static void __exit screen_exit( void )
{
   printk("screen: exit called\n");

   send_cmd(SLPIN);
   screen_delay(10);
   send_cmd(DISOFF);
   screen_delay(10);

   ssp_exit(&gSpiDevice);

    unregister_chrdev( SCREEN_MAJOR, DEVICE_NAME );
}

//**********************************************************************
// MODULE SETUP

module_init(screen_init);
module_exit(screen_exit);

MODULE_AUTHOR("Dan Taylor");
MODULE_DESCRIPTION("Screen Driver");
MODULE_LICENSE("GPL");