hecubafb.c

Go to the documentation of this file.

/*
 * linux/drivers/video/hecubafb.c -- FB driver for Hecuba/Apollo controller
 *
 * Copyright (C) 2006, Jaya Kumar
 * This work was sponsored by CIS(M) Sdn Bhd
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file COPYING in the main directory of this archive for
 * more details.
 *
 * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
 * This work was possible because of apollo display code from E-Ink's website
 * http://support.eink.com/community
 * All information used to write this code is from public material made
 * available by E-Ink on its support site. Some commands such as 0xA4
 * were found by looping through cmd=0x00 thru 0xFF and supplying random
 * values. There are other commands that the display is capable of,
 * beyond the 5 used here but they are more complex.
 *
 * This driver is written to be used with the Hecuba display architecture.
 * The actual display chip is called Apollo and the interface electronics
 * it needs is called Hecuba.
 *
 * It is intended to be architecture independent. A board specific driver
 * must be used to perform all the physical IO interactions. An example
 * is provided as n411.c
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/uaccess.h>

#include <video/hecubafb.h>

/* Display specific information */
#define DPY_W 600
#define DPY_H 800

static struct fb_fix_screeninfo hecubafb_fix __devinitdata = {
    .id =       "hecubafb",
    .type =     FB_TYPE_PACKED_PIXELS,
    .visual =   FB_VISUAL_MONO01,
    .xpanstep = 0,
    .ypanstep = 0,
    .ywrapstep =    0,
    .line_length =  DPY_W,
    .accel =    FB_ACCEL_NONE,
};

static struct fb_var_screeninfo hecubafb_var __devinitdata = {
    .xres       = DPY_W,
    .yres       = DPY_H,
    .xres_virtual   = DPY_W,
    .yres_virtual   = DPY_H,
    .bits_per_pixel = 1,
    .nonstd     = 1,
};

/* main hecubafb functions */

static void apollo_send_data(struct hecubafb_par *par, unsigned char data)
{
    /* set data */
    par->board->set_data(par, data);

    /* set DS low */
    par->board->set_ctl(par, HCB_DS_BIT, 0);

    /* wait for ack */
    par->board->wait_for_ack(par, 0);

    /* set DS hi */
    par->board->set_ctl(par, HCB_DS_BIT, 1);

    /* wait for ack to clear */
    par->board->wait_for_ack(par, 1);
}

static void apollo_send_command(struct hecubafb_par *par, unsigned char data)
{
    /* command so set CD to high */
    par->board->set_ctl(par, HCB_CD_BIT, 1);

    /* actually strobe with command */
    apollo_send_data(par, data);

    /* clear CD back to low */
    par->board->set_ctl(par, HCB_CD_BIT, 0);
}

static void hecubafb_dpy_update(struct hecubafb_par *par)
{
    int i;
    unsigned char *buf = (unsigned char __force *)par->info->screen_base;

    apollo_send_command(par, APOLLO_START_NEW_IMG);

    for (i=0; i < (DPY_W*DPY_H/8); i++) {
        apollo_send_data(par, *(buf++));
    }

    apollo_send_command(par, APOLLO_STOP_IMG_DATA);
    apollo_send_command(par, APOLLO_DISPLAY_IMG);
}

/* this is called back from the deferred io workqueue */
static void hecubafb_dpy_deferred_io(struct fb_info *info,
                struct list_head *pagelist)
{
    hecubafb_dpy_update(info->par);
}

static void hecubafb_fillrect(struct fb_info *info,
                   const struct fb_fillrect *rect)
{
    struct hecubafb_par *par = info->par;

    sys_fillrect(info, rect);

    hecubafb_dpy_update(par);
}

static void hecubafb_copyarea(struct fb_info *info,
                   const struct fb_copyarea *area)
{
    struct hecubafb_par *par = info->par;

    sys_copyarea(info, area);

    hecubafb_dpy_update(par);
}

static void hecubafb_imageblit(struct fb_info *info,
                const struct fb_image *image)
{
    struct hecubafb_par *par = info->par;

    sys_imageblit(info, image);

    hecubafb_dpy_update(par);
}

/*
 * this is the slow path from userspace. they can seek and write to
 * the fb. it's inefficient to do anything less than a full screen draw
 */
static ssize_t hecubafb_write(struct fb_info *info, const char __user *buf,
                size_t count, loff_t *ppos)
{
    struct hecubafb_par *par = info->par;
    unsigned long p = *ppos;
    void *dst;
    int err = 0;
    unsigned long total_size;

    if (info->state != FBINFO_STATE_RUNNING)
        return -EPERM;

    total_size = info->fix.smem_len;

    if (p > total_size)
        return -EFBIG;

    if (count > total_size) {
        err = -EFBIG;
        count = total_size;
    }

    if (count + p > total_size) {
        if (!err)
            err = -ENOSPC;

        count = total_size - p;
    }

    dst = (void __force *) (info->screen_base + p);

    if (copy_from_user(dst, buf, count))
        err = -EFAULT;

    if  (!err)
        *ppos += count;

    hecubafb_dpy_update(par);

    return (err) ? err : count;
}

static struct fb_ops hecubafb_ops = {
    .owner      = THIS_MODULE,
    .fb_read        = fb_sys_read,
    .fb_write   = hecubafb_write,
    .fb_fillrect    = hecubafb_fillrect,
    .fb_copyarea    = hecubafb_copyarea,
    .fb_imageblit   = hecubafb_imageblit,
};

static struct fb_deferred_io hecubafb_defio = {
    .delay      = HZ,
    .deferred_io    = hecubafb_dpy_deferred_io,
};

static int __devinit hecubafb_probe(struct platform_device *dev)
{
    struct fb_info *info;
    struct hecuba_board *board;
    int retval = -ENOMEM;
    int videomemorysize;
    unsigned char *videomemory;
    struct hecubafb_par *par;

    /* pick up board specific routines */
    board = dev->dev.platform_data;
    if (!board)
        return -EINVAL;

    /* try to count device specific driver, if can't, platform recalls */
    if (!try_module_get(board->owner))
        return -ENODEV;

    videomemorysize = (DPY_W*DPY_H)/8;

    videomemory = vzalloc(videomemorysize);
    if (!videomemory)
        goto err_videomem_alloc;

    info = framebuffer_alloc(sizeof(struct hecubafb_par), &dev->dev);
    if (!info)
        goto err_fballoc;

    info->screen_base = (char __force __iomem *)videomemory;
    info->fbops = &hecubafb_ops;

    info->var = hecubafb_var;
    info->fix = hecubafb_fix;
    info->fix.smem_len = videomemorysize;
    par = info->par;
    par->info = info;
    par->board = board;
    par->send_command = apollo_send_command;
    par->send_data = apollo_send_data;

    info->flags = FBINFO_FLAG_DEFAULT | FBINFO_VIRTFB;

    info->fbdefio = &hecubafb_defio;
    fb_deferred_io_init(info);

    retval = register_framebuffer(info);
    if (retval < 0)
        goto err_fbreg;
    platform_set_drvdata(dev, info);

    printk(KERN_INFO
           "fb%d: Hecuba frame buffer device, using %dK of video memory\n",
           info->node, videomemorysize >> 10);

    /* this inits the dpy */
    retval = par->board->init(par);
    if (retval < 0)
        goto err_fbreg;

    return 0;
err_fbreg:
    framebuffer_release(info);
err_fballoc:
    vfree(videomemory);
err_videomem_alloc:
    module_put(board->owner);
    return retval;
}

static int __devexit hecubafb_remove(struct platform_device *dev)
{
    struct fb_info *info = platform_get_drvdata(dev);

    if (info) {
        struct hecubafb_par *par = info->par;
        fb_deferred_io_cleanup(info);
        unregister_framebuffer(info);
        vfree((void __force *)info->screen_base);
        if (par->board->remove)
            par->board->remove(par);
        module_put(par->board->owner);
        framebuffer_release(info);
    }
    return 0;
}

static struct platform_driver hecubafb_driver = {
    .probe  = hecubafb_probe,
    .remove = __devexit_p(hecubafb_remove),
    .driver = {
        .owner  = THIS_MODULE,
        .name   = "hecubafb",
    },
};

static int __init hecubafb_init(void)
{
    return platform_driver_register(&hecubafb_driver);
}

static void __exit hecubafb_exit(void)
{
    platform_driver_unregister(&hecubafb_driver);
}

module_init(hecubafb_init);
module_exit(hecubafb_exit);

MODULE_DESCRIPTION("fbdev driver for Hecuba/Apollo controller");
MODULE_AUTHOR("Jaya Kumar");
MODULE_LICENSE("GPL");