linux/drivers/video/n411.c
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   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
  41static unsigned long dio_addr;
  42static unsigned long cio_addr;
  43static unsigned long c2io_addr;
  44static unsigned long splashval;
  45static unsigned int nosplash;
  46static unsigned char ctl;
  47
  48static 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
  68static unsigned char n411_get_ctl(struct hecubafb_par *par)
  69{
  70        return inb(c2io_addr);
  71}
  72
  73static void n411_set_data(struct hecubafb_par *par, unsigned char value)
  74{
  75        outb(value, dio_addr);
  76}
  77
  78static 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
  95static 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
 121static 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
 144static 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
 152static struct platform_device *n411_device;
 153static 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
 180static void __exit n411_exit(void)
 181{
 182        platform_device_unregister(n411_device);
 183}
 184
 185module_init(n411_init);
 186module_exit(n411_exit);
 187
 188module_param(nosplash, uint, 0);
 189MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
 190module_param(dio_addr, ulong, 0);
 191MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
 192module_param(cio_addr, ulong, 0);
 193MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
 194module_param(c2io_addr, ulong, 0);
 195MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
 196module_param(splashval, ulong, 0);
 197MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");
 198
 199MODULE_DESCRIPTION("board driver for n411 hecuba/apollo epd kit");
 200MODULE_AUTHOR("Jaya Kumar");
 201MODULE_LICENSE("GPL");
 202
 203
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