cobalt_lcdfb.c

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/*
 *  Cobalt/SEAD3 LCD frame buffer driver.
 *
 *  Copyright (C) 2008  Yoichi Yuasa <[email protected]>
 *  Copyright (C) 2012  MIPS Technologies, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>
#include <linux/module.h>

/*
 * Cursor position address
 * \X  0    1    2  ...  14   15
 * Y+----+----+----+---+----+----+
 * 0|0x00|0x01|0x02|...|0x0e|0x0f|
 *  +----+----+----+---+----+----+
 * 1|0x40|0x41|0x42|...|0x4e|0x4f|
 *  +----+----+----+---+----+----+
 */
#define LCD_DATA_REG_OFFSET 0x10
#define LCD_XRES_MAX        16
#define LCD_YRES_MAX        2
#define LCD_CHARS_MAX       32

#define LCD_CLEAR       0x01
#define LCD_CURSOR_MOVE_HOME    0x02
#define LCD_RESET       0x06
#define LCD_OFF         0x08
#define LCD_CURSOR_OFF      0x0c
#define LCD_CURSOR_BLINK_OFF    0x0e
#define LCD_CURSOR_ON       0x0f
#define LCD_ON          LCD_CURSOR_ON
#define LCD_CURSOR_MOVE_LEFT    0x10
#define LCD_CURSOR_MOVE_RIGHT   0x14
#define LCD_DISPLAY_LEFT    0x18
#define LCD_DISPLAY_RIGHT   0x1c
#define LCD_PRERESET        0x3f    /* execute 4 times continuously */
#define LCD_BUSY        0x80

#define LCD_GRAPHIC_MODE    0x40
#define LCD_TEXT_MODE       0x80
#define LCD_CUR_POS_MASK    0x7f

#define LCD_CUR_POS(x)      ((x) & LCD_CUR_POS_MASK)
#define LCD_TEXT_POS(x)     ((x) | LCD_TEXT_MODE)

#ifdef CONFIG_MIPS_COBALT
static inline void lcd_write_control(struct fb_info *info, u8 control)
{
    writel((u32)control << 24, info->screen_base);
}

static inline u8 lcd_read_control(struct fb_info *info)
{
    return readl(info->screen_base) >> 24;
}

static inline void lcd_write_data(struct fb_info *info, u8 data)
{
    writel((u32)data << 24, info->screen_base + LCD_DATA_REG_OFFSET);
}

static inline u8 lcd_read_data(struct fb_info *info)
{
    return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
}
#else

#define LCD_CTL         0x00
#define LCD_DATA        0x08
#define CPLD_STATUS     0x10
#define CPLD_DATA       0x18

static inline void cpld_wait(struct fb_info *info)
{
    do {
    } while (readl(info->screen_base + CPLD_STATUS) & 1);
}

static inline void lcd_write_control(struct fb_info *info, u8 control)
{
    cpld_wait(info);
    writel(control, info->screen_base + LCD_CTL);
}

static inline u8 lcd_read_control(struct fb_info *info)
{
    cpld_wait(info);
    readl(info->screen_base + LCD_CTL);
    cpld_wait(info);
    return readl(info->screen_base + CPLD_DATA) & 0xff;
}

static inline void lcd_write_data(struct fb_info *info, u8 data)
{
    cpld_wait(info);
    writel(data, info->screen_base + LCD_DATA);
}

static inline u8 lcd_read_data(struct fb_info *info)
{
    cpld_wait(info);
    readl(info->screen_base + LCD_DATA);
    cpld_wait(info);
    return readl(info->screen_base + CPLD_DATA) & 0xff;
}
#endif

static int lcd_busy_wait(struct fb_info *info)
{
    u8 val = 0;
    int timeout = 10, retval = 0;

    do {
        val = lcd_read_control(info);
        val &= LCD_BUSY;
        if (val != LCD_BUSY)
            break;

        if (msleep_interruptible(1))
            return -EINTR;

        timeout--;
    } while (timeout);

    if (val == LCD_BUSY)
        retval = -EBUSY;

    return retval;
}

static void lcd_clear(struct fb_info *info)
{
    int i;

    for (i = 0; i < 4; i++) {
        udelay(150);

        lcd_write_control(info, LCD_PRERESET);
    }

    udelay(150);

    lcd_write_control(info, LCD_CLEAR);

    udelay(150);

    lcd_write_control(info, LCD_RESET);
}

static struct fb_fix_screeninfo cobalt_lcdfb_fix __devinitdata = {
    .id     = "cobalt-lcd",
    .type       = FB_TYPE_TEXT,
    .type_aux   = FB_AUX_TEXT_MDA,
    .visual     = FB_VISUAL_MONO01,
    .line_length    = LCD_XRES_MAX,
    .accel      = FB_ACCEL_NONE,
};

static ssize_t cobalt_lcdfb_read(struct fb_info *info, char __user *buf,
                 size_t count, loff_t *ppos)
{
    char src[LCD_CHARS_MAX];
    unsigned long pos;
    int len, retval = 0;

    pos = *ppos;
    if (pos >= LCD_CHARS_MAX || count == 0)
        return 0;

    if (count > LCD_CHARS_MAX)
        count = LCD_CHARS_MAX;

    if (pos + count > LCD_CHARS_MAX)
        count = LCD_CHARS_MAX - pos;

    for (len = 0; len < count; len++) {
        retval = lcd_busy_wait(info);
        if (retval < 0)
            break;

        lcd_write_control(info, LCD_TEXT_POS(pos));

        retval = lcd_busy_wait(info);
        if (retval < 0)
            break;

        src[len] = lcd_read_data(info);
        if (pos == 0x0f)
            pos = 0x40;
        else
            pos++;
    }

    if (retval < 0 && signal_pending(current))
        return -ERESTARTSYS;

    if (copy_to_user(buf, src, len))
        return -EFAULT;

    *ppos += len;

    return len;
}

static ssize_t cobalt_lcdfb_write(struct fb_info *info, const char __user *buf,
                  size_t count, loff_t *ppos)
{
    char dst[LCD_CHARS_MAX];
    unsigned long pos;
    int len, retval = 0;

    pos = *ppos;
    if (pos >= LCD_CHARS_MAX || count == 0)
        return 0;

    if (count > LCD_CHARS_MAX)
        count = LCD_CHARS_MAX;

    if (pos + count > LCD_CHARS_MAX)
        count = LCD_CHARS_MAX - pos;

    if (copy_from_user(dst, buf, count))
        return -EFAULT;

    for (len = 0; len < count; len++) {
        retval = lcd_busy_wait(info);
        if (retval < 0)
            break;

        lcd_write_control(info, LCD_TEXT_POS(pos));

        retval = lcd_busy_wait(info);
        if (retval < 0)
            break;

        lcd_write_data(info, dst[len]);
        if (pos == 0x0f)
            pos = 0x40;
        else
            pos++;
    }

    if (retval < 0 && signal_pending(current))
        return -ERESTARTSYS;

    *ppos += len;

    return len;
}

static int cobalt_lcdfb_blank(int blank_mode, struct fb_info *info)
{
    int retval;

    retval = lcd_busy_wait(info);
    if (retval < 0)
        return retval;

    switch (blank_mode) {
    case FB_BLANK_UNBLANK:
        lcd_write_control(info, LCD_ON);
        break;
    default:
        lcd_write_control(info, LCD_OFF);
        break;
    }

    return 0;
}

static int cobalt_lcdfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
    u32 x, y;
    int retval;

    switch (cursor->set) {
    case FB_CUR_SETPOS:
        x = cursor->image.dx;
        y = cursor->image.dy;
        if (x >= LCD_XRES_MAX || y >= LCD_YRES_MAX)
            return -EINVAL;

        retval = lcd_busy_wait(info);
        if (retval < 0)
            return retval;

        lcd_write_control(info,
                  LCD_TEXT_POS(info->fix.line_length * y + x));
        break;
    default:
        return -EINVAL;
    }

    retval = lcd_busy_wait(info);
    if (retval < 0)
        return retval;

    if (cursor->enable)
        lcd_write_control(info, LCD_CURSOR_ON);
    else
        lcd_write_control(info, LCD_CURSOR_OFF);

    return 0;
}

static struct fb_ops cobalt_lcd_fbops = {
    .owner      = THIS_MODULE,
    .fb_read    = cobalt_lcdfb_read,
    .fb_write   = cobalt_lcdfb_write,
    .fb_blank   = cobalt_lcdfb_blank,
    .fb_cursor  = cobalt_lcdfb_cursor,
};

static int __devinit cobalt_lcdfb_probe(struct platform_device *dev)
{
    struct fb_info *info;
    struct resource *res;
    int retval;

    info = framebuffer_alloc(0, &dev->dev);
    if (!info)
        return -ENOMEM;

    res = platform_get_resource(dev, IORESOURCE_MEM, 0);
    if (!res) {
        framebuffer_release(info);
        return -EBUSY;
    }

    info->screen_size = resource_size(res);
    info->screen_base = devm_ioremap(&dev->dev, res->start,
                     info->screen_size);
    info->fbops = &cobalt_lcd_fbops;
    info->fix = cobalt_lcdfb_fix;
    info->fix.smem_start = res->start;
    info->fix.smem_len = info->screen_size;
    info->pseudo_palette = NULL;
    info->par = NULL;
    info->flags = FBINFO_DEFAULT;

    retval = register_framebuffer(info);
    if (retval < 0) {
        framebuffer_release(info);
        return retval;
    }

    platform_set_drvdata(dev, info);

    lcd_clear(info);

    printk(KERN_INFO "fb%d: Cobalt server LCD frame buffer device\n",
        info->node);

    return 0;
}

static int __devexit cobalt_lcdfb_remove(struct platform_device *dev)
{
    struct fb_info *info;

    info = platform_get_drvdata(dev);
    if (info) {
        unregister_framebuffer(info);
        framebuffer_release(info);
    }

    return 0;
}

static struct platform_driver cobalt_lcdfb_driver = {
    .probe  = cobalt_lcdfb_probe,
    .remove = __devexit_p(cobalt_lcdfb_remove),
    .driver = {
        .name   = "cobalt-lcd",
        .owner  = THIS_MODULE,
    },
};

static int __init cobalt_lcdfb_init(void)
{
    return platform_driver_register(&cobalt_lcdfb_driver);
}

static void __exit cobalt_lcdfb_exit(void)
{
    platform_driver_unregister(&cobalt_lcdfb_driver);
}

module_init(cobalt_lcdfb_init);
module_exit(cobalt_lcdfb_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Yoichi Yuasa");
MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");