drivers/video/n411.c

   1 /*
   2  * linux/drivers/video/n411.c -- Platform device for N411 EPD kit
   3  *
   4  * Copyright (C) 2008, Jaya Kumar
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License. See the file COPYING in the main directory of this archive for
   8  * more details.
   9  *
  10  * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
  11  *
  12  * This driver is written to be used with the Hecuba display controller
  13  * board, and tested with the EInk 800x600 display in 1 bit mode.
  14  * The interface between Hecuba and the host is TTL based GPIO. The
  15  * GPIO requirements are 8 writable data lines and 6 lines for control.
  16  * Only 4 of the controls are actually used here but 6 for future use.
  17  * The driver requires the IO addresses for data and control GPIO at
  18  * load time. It is also possible to use this display with a standard
  19  * PC parallel port.
  20  *
  21  * General notes:
  22  * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR c2io_addr=0xIOADDR
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/kernel.h>
  28 #include <linux/errno.h>
  29 #include <linux/string.h>
  30 #include <linux/delay.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/fb.h>
  33 #include <linux/init.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/list.h>
  36 #include <linux/uaccess.h>
  37 #include <linux/irq.h>
  38
  39 #include <video/hecubafb.h>
  40
  41 static unsigned long dio_addr;
  42 static unsigned long cio_addr;
  43 static unsigned long c2io_addr;
  44 static unsigned long splashval;
  45 static unsigned int nosplash;
  46 static unsigned char ctl;
  47
  48 static void n411_set_ctl(struct hecubafb_par *par, unsigned char bit, unsigned
  49                                                         char state)
  50 {
  51         switch (bit) {
  52         case HCB_CD_BIT:
  53                 if (state)
  54                         ctl &= ~(HCB_CD_BIT);
  55                 else
  56                         ctl |= HCB_CD_BIT;
  57                 break;
  58         case HCB_DS_BIT:
  59                 if (state)
  60                         ctl &= ~(HCB_DS_BIT);
  61                 else
  62                         ctl |= HCB_DS_BIT;
  63                 break;
  64         }
  65         outb(ctl, cio_addr);
  66 }
  67
  68 static unsigned char n411_get_ctl(struct hecubafb_par *par)
  69 {
  70         return inb(c2io_addr);
  71 }
  72
  73 static void n411_set_data(struct hecubafb_par *par, unsigned char value)
  74 {
  75         outb(value, dio_addr);
  76 }
  77
  78 static void n411_wait_for_ack(struct hecubafb_par *par, int clear)
  79 {
  80         int timeout;
  81         unsigned char tmp;
  82
  83         timeout = 500;
  84         do {
  85                 tmp = n411_get_ctl(par);
  86                 if ((tmp & HCB_ACK_BIT) && (!clear))
  87                         return;
  88                 else if (!(tmp & HCB_ACK_BIT) && (clear))
  89                         return;
  90                 udelay(1);
  91         } while (timeout--);
  92         printk(KERN_ERR "timed out waiting for ack\n");
  93 }
  94
  95 static int n411_init_control(struct hecubafb_par *par)
  96 {
  97         unsigned char tmp;
  98         /* for init, we want the following setup to be set:
  99         WUP = lo
 100         ACK = hi
 101         DS = hi
 102         RW = hi
 103         CD = lo
 104         */
 105
 106         /* write WUP to lo, DS to hi, RW to hi, CD to lo */
 107         ctl = HCB_WUP_BIT | HCB_RW_BIT | HCB_CD_BIT ;
 108         n411_set_ctl(par, HCB_DS_BIT, 1);
 109
 110         /* check ACK is not lo */
 111         tmp = n411_get_ctl(par);
 112         if (tmp & HCB_ACK_BIT) {
 113                 printk(KERN_ERR "Fail because ACK is already low\n");
 114                 return -ENXIO;
 115         }
 116
 117         return 0;
 118 }
 119
 120
 121 static int n411_init_board(struct hecubafb_par *par)
 122 {
 123         int retval;
 124
 125         retval = n411_init_control(par);
 126         if (retval)
 127                 return retval;
 128
 129         par->send_command(par, APOLLO_INIT_DISPLAY);
 130         par->send_data(par, 0x81);
 131
 132         /* have to wait while display resets */
 133         udelay(1000);
 134
 135         /* if we were told to splash the screen, we just clear it */
 136         if (!nosplash) {
 137                 par->send_command(par, APOLLO_ERASE_DISPLAY);
 138                 par->send_data(par, splashval);
 139         }
 140
 141         return 0;
 142 }
 143
 144 static struct hecuba_board n411_board = {
 145         .owner                  = THIS_MODULE,
 146         .init                   = n411_init_board,
 147         .set_ctl                = n411_set_ctl,
 148         .set_data               = n411_set_data,
 149         .wait_for_ack           = n411_wait_for_ack,
 150 };
 151
 152 static struct platform_device *n411_device;
 153 static int __init n411_init(void)
 154 {
 155         int ret;
 156         if (!dio_addr || !cio_addr || !c2io_addr) {
 157                 printk(KERN_WARNING "no IO addresses supplied\n");
 158                 return -EINVAL;
 159         }
 160
 161         /* request our platform independent driver */
 162         request_module("hecubafb");
 163
 164         n411_device = platform_device_alloc("hecubafb", -1);
 165         if (!n411_device)
 166                 return -ENOMEM;
 167
 168         platform_device_add_data(n411_device, &n411_board, sizeof(n411_board));
 169
 170         /* this _add binds hecubafb to n411. hecubafb refcounts n411 */
 171         ret = platform_device_add(n411_device);
 172
 173         if (ret)
 174                 platform_device_put(n411_device);
 175
 176         return ret;
 177
 178 }
 179
 180 static void __exit n411_exit(void)
 181 {
 182         platform_device_unregister(n411_device);
 183 }
 184
 185 module_init(n411_init);
 186 module_exit(n411_exit);
 187
 188 module_param(nosplash, uint, 0);
 189 MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
 190 module_param(dio_addr, ulong, 0);
 191 MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
 192 module_param(cio_addr, ulong, 0);
 193 MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
 194 module_param(c2io_addr, ulong, 0);
 195 MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
 196 module_param(splashval, ulong, 0);
 197 MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");
 198
 199 MODULE_DESCRIPTION("board driver for n411 hecuba/apollo epd kit");
 200 MODULE_AUTHOR("Jaya Kumar");
 201 MODULE_LICENSE("GPL");
 202