[PATCH] Add section on function return values to CodingStyle

[linux-2.6/mini2440.git] / drivers / video / epson1355fb.c

/*
 * linux/drivers/video/epson1355fb.c -- Epson S1D13505 frame buffer for 2.5.
 *
 * Epson Research S1D13505 Embedded RAMDAC LCD/CRT Controller
 *   (previously known as SED1355)
 *
 * Cf. http://www.erd.epson.com/vdc/html/S1D13505.html
 *
 *
 * Copyright (C) Hewlett-Packard Company.  All rights reserved.
 *
 * Written by Christopher Hoover <ch@hpl.hp.com>
 *
 * Adapted from:
 *
 *  linux/drivers/video/skeletonfb.c
 *  Modified to new api Jan 2001 by James Simmons (jsimmons@infradead.org)
 *  Created 28 Dec 1997 by Geert Uytterhoeven
 *
 *  linux/drivers/video/epson1355fb.c (2.4 driver)
 *  Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
 *
 * 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.
 *
 *
 * Noteworthy Issues
 * -----------------
 *
 * This driver is complicated by the fact that this is a 16-bit chip
 * and, on at least one platform (ceiva), we can only do 16-bit reads
 * and writes to the framebuffer.  We hide this from user space
 * except in the case of mmap().
 *
 *
 * To Do
 * -----
 *
 * - Test 8-bit pseudocolor mode
 * - Allow setting bpp, virtual resolution
 * - Implement horizontal panning
 * - (maybe) Implement hardware cursor
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>

#include <asm/types.h>
#include <asm/io.h>
#include <asm/uaccess.h>

#include <video/epson1355.h>

struct epson1355_par {
        unsigned long reg_addr;
};

/* ------------------------------------------------------------------------- */

#ifdef CONFIG_SUPERH

static inline u8 epson1355_read_reg(int index)
{
        return ctrl_inb(par.reg_addr + index);
}

static inline void epson1355_write_reg(u8 data, int index)
{
        ctrl_outb(data, par.reg_addr + index);
}

#elif defined(CONFIG_ARM)

# ifdef CONFIG_ARCH_CEIVA
#  include <asm/arch/hardware.h>
#  define EPSON1355FB_BASE_PHYS (CEIVA_PHYS_SED1355)
# endif

static inline u8 epson1355_read_reg(struct epson1355_par *par, int index)
{
        return __raw_readb(par->reg_addr + index);
}

static inline void epson1355_write_reg(struct epson1355_par *par, u8 data, int index)
{
        __raw_writeb(data, par->reg_addr + index);
}

#else
# error "no architecture-specific epson1355_{read,write}_reg"
#endif

#ifndef EPSON1355FB_BASE_PHYS
# error  "EPSON1355FB_BASE_PHYS is not defined"
#endif

#define EPSON1355FB_REGS_OFS    (0)
#define EPSON1355FB_REGS_PHYS   (EPSON1355FB_BASE_PHYS + EPSON1355FB_REGS_OFS)
#define EPSON1355FB_REGS_LEN    (64)

#define EPSON1355FB_FB_OFS      (0x00200000)
#define EPSON1355FB_FB_PHYS     (EPSON1355FB_BASE_PHYS + EPSON1355FB_FB_OFS)
#define EPSON1355FB_FB_LEN      (2 * 1024 * 1024)

/* ------------------------------------------------------------------------- */

static inline u16 epson1355_read_reg16(struct epson1355_par *par, int index)
{
        u8 lo = epson1355_read_reg(par, index);
        u8 hi = epson1355_read_reg(par, index + 1);

        return (hi << 8) | lo;
}

static inline void epson1355_write_reg16(struct epson1355_par *par, u16 data, int index)
{
        u8 lo = data & 0xff;
        u8 hi = (data >> 8) & 0xff;

        epson1355_write_reg(par, lo, index);
        epson1355_write_reg(par, hi, index + 1);
}

static inline u32 epson1355_read_reg20(struct epson1355_par *par, int index)
{
        u8 b0 = epson1355_read_reg(par, index);
        u8 b1 = epson1355_read_reg(par, index + 1);
        u8 b2 = epson1355_read_reg(par, index + 2);

        return (b2 & 0x0f) << 16 | (b1 << 8) | b0;
}

static inline void epson1355_write_reg20(struct epson1355_par *par, u32 data, int index)
{
        u8 b0 = data & 0xff;
        u8 b1 = (data >> 8) & 0xff;
        u8 b2 = (data >> 16) & 0x0f;

        epson1355_write_reg(par, b0, index);
        epson1355_write_reg(par, b1, index + 1);
        epson1355_write_reg(par, b2, index + 2);
}

/* ------------------------------------------------------------------------- */

static void set_lut(struct epson1355_par *par, u8 index, u8 r, u8 g, u8 b)
{
        epson1355_write_reg(par, index, REG_LUT_ADDR);
        epson1355_write_reg(par, r, REG_LUT_DATA);
        epson1355_write_reg(par, g, REG_LUT_DATA);
        epson1355_write_reg(par, b, REG_LUT_DATA);
}


/**
 *      epson1355fb_setcolreg - sets a color register.
 *      @regno: Which register in the CLUT we are programming
 *      @red: The red value which can be up to 16 bits wide
 *      @green: The green value which can be up to 16 bits wide
 *      @blue:  The blue value which can be up to 16 bits wide.
 *      @transp: If supported the alpha value which can be up to 16 bits wide.
 *      @info: frame buffer info structure
 *
 *      Returns negative errno on error, or zero on success.
 */
static int epson1355fb_setcolreg(unsigned regno, unsigned r, unsigned g,
                                 unsigned b, unsigned transp,
                                 struct fb_info *info)
{
        struct epson1355_par *par = info->par;

        if (info->var.grayscale)
                r = g = b = (19595 * r + 38470 * g + 7471 * b) >> 16;

        switch (info->fix.visual) {
        case FB_VISUAL_TRUECOLOR:
                if (regno >= 16)
                        return -EINVAL;

                ((u32 *) info->pseudo_palette)[regno] =
                    (r & 0xf800) | (g & 0xfc00) >> 5 | (b & 0xf800) >> 11;

                break;
        case FB_VISUAL_PSEUDOCOLOR:
                if (regno >= 256)
                        return -EINVAL;

                set_lut(par, regno, r >> 8, g >> 8, b >> 8);

                break;
        default:
                return -ENOSYS;
        }
        return 0;
}

/* ------------------------------------------------------------------------- */

/**
 *      epson1355fb_pan_display - Pans the display.
 *      @var: frame buffer variable screen structure
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *      Pan (or wrap, depending on the `vmode' field) the display using the
 *      `xoffset' and `yoffset' fields of the `var' structure.
 *      If the values don't fit, return -EINVAL.
 *
 *      Returns negative errno on error, or zero on success.
 */
static int epson1355fb_pan_display(struct fb_var_screeninfo *var,
                                   struct fb_info *info)
{
        struct epson1355_par *par = info->par;
        u32 start;

        if (var->xoffset != 0)  /* not yet ... */
                return -EINVAL;

        if (var->yoffset + info->var.yres > info->var.yres_virtual)
                return -EINVAL;

        start = (info->fix.line_length >> 1) * var->yoffset;

        epson1355_write_reg20(par, start, REG_SCRN1_DISP_START_ADDR0);

        return 0;
}

/* ------------------------------------------------------------------------- */

static void lcd_enable(struct epson1355_par *par, int enable)
{
        u8 mode = epson1355_read_reg(par, REG_DISPLAY_MODE);

        if (enable)
                mode |= 1;
        else
                mode &= ~1;

        epson1355_write_reg(par, mode, REG_DISPLAY_MODE);
}

#if defined(CONFIG_ARCH_CEIVA)
static void backlight_enable(int enable)
{
        /* ### this should be protected by a spinlock ... */
        u8 pddr = clps_readb(PDDR);
        if (enable)
                pddr |= (1 << 5);
        else
                pddr &= ~(1 << 5);
        clps_writeb(pddr, PDDR);
}
#else
static void backlight_enable(int enable)
{
}
#endif


/**
 *      epson1355fb_blank - blanks the display.
 *      @blank_mode: the blank mode we want.
 *      @info: frame buffer structure that represents a single frame buffer
 *
 *      Blank the screen if blank_mode != 0, else unblank. Return 0 if
 *      blanking succeeded, != 0 if un-/blanking failed due to e.g. a
 *      video mode which doesn't support it. Implements VESA suspend
 *      and powerdown modes on hardware that supports disabling hsync/vsync:
 *      blank_mode == 2: suspend vsync
 *      blank_mode == 3: suspend hsync
 *      blank_mode == 4: powerdown
 *
 *      Returns negative errno on error, or zero on success.
 *
 */
static int epson1355fb_blank(int blank_mode, struct fb_info *info)
{
        struct epson1355_par *par = info->par;

        switch (blank_mode) {
        case FB_BLANK_UNBLANKING:
        case FB_BLANK_NORMAL:
                lcd_enable(par, 1);
                backlight_enable(1);
                break;
        case FB_BLANK_VSYNC_SUSPEND:
        case FB_BLANK_HSYNC_SUSPEND:
                backlight_enable(0);
                break;
        case FB_BLANK_POWERDOWN:
                backlight_enable(0);
                lcd_enable(par, 0);
                break;
        default:
                return -EINVAL;
        }

        /* let fbcon do a soft blank for us */
        return (blank_mode == FB_BLANK_NORMAL) ? 1 : 0;
}

/* ------------------------------------------------------------------------- */

/*
 * We can't use the cfb generic routines, as we have to limit
 * ourselves to 16-bit or 8-bit loads and stores to this 16-bit
 * chip.
 */

static inline void epson1355fb_fb_writel(unsigned long v, unsigned long *a)
{
        u16 *p = (u16 *) a;
        u16 l = v & 0xffff;
        u16 h = v >> 16;

        fb_writew(l, p);
        fb_writew(h, p + 1);
}

static inline unsigned long epson1355fb_fb_readl(const unsigned long *a)
{
        const u16 *p = (u16 *) a;
        u16 l = fb_readw(p);
        u16 h = fb_readw(p + 1);

        return (h << 16) | l;
}

#define FB_READL epson1355fb_fb_readl
#define FB_WRITEL epson1355fb_fb_writel

/* ------------------------------------------------------------------------- */

static inline unsigned long copy_from_user16(void *to, const void *from,
                                             unsigned long n)
{
        u16 *dst = (u16 *) to;
        u16 *src = (u16 *) from;

        if (!access_ok(VERIFY_READ, from, n))
                return n;

        while (n > 1) {
                u16 v;
                if (__get_user(v, src))
                        return n;

                fb_writew(v, dst);

                src++, dst++;
                n -= 2;
        }

        if (n) {
                u8 v;

                if (__get_user(v, ((u8 *) src)))
                        return n;

                fb_writeb(v, dst);
        }
        return 0;
}

static inline unsigned long copy_to_user16(void *to, const void *from,
                                           unsigned long n)
{
        u16 *dst = (u16 *) to;
        u16 *src = (u16 *) from;

        if (!access_ok(VERIFY_WRITE, to, n))
                return n;

        while (n > 1) {
                u16 v = fb_readw(src);

                if (__put_user(v, dst))
                        return n;

                src++, dst++;
                n -= 2;
        }

        if (n) {
                u8 v = fb_readb(src);

                if (__put_user(v, ((u8 *) dst)))
                        return n;
        }
        return 0;
}


static ssize_t
epson1355fb_read(struct file *file, char *buf, size_t count, loff_t * ppos)
{
        struct inode *inode = file->f_dentry->d_inode;
        int fbidx = iminor(inode);
        struct fb_info *info = registered_fb[fbidx];
        unsigned long p = *ppos;

        /* from fbmem.c except for our own copy_*_user */
        if (!info || !info->screen_base)
                return -ENODEV;

        if (p >= info->fix.smem_len)
                return 0;
        if (count >= info->fix.smem_len)
                count = info->fix.smem_len;
        if (count + p > info->fix.smem_len)
                count = info->fix.smem_len - p;

        if (count) {
                char *base_addr;

                base_addr = info->screen_base;
                count -= copy_to_user16(buf, base_addr + p, count);
                if (!count)
                        return -EFAULT;
                *ppos += count;
        }
        return count;
}

static ssize_t
epson1355fb_write(struct file *file, const char *buf,
                  size_t count, loff_t * ppos)
{
        struct inode *inode = file->f_dentry->d_inode;
        int fbidx = iminor(inode);
        struct fb_info *info = registered_fb[fbidx];
        unsigned long p = *ppos;
        int err;

        /* from fbmem.c except for our own copy_*_user */
        if (!info || !info->screen_base)
                return -ENODEV;

        /* from fbmem.c except for our own copy_*_user */
        if (p > info->fix.smem_len)
                return -ENOSPC;
        if (count >= info->fix.smem_len)
                count = info->fix.smem_len;
        err = 0;
        if (count + p > info->fix.smem_len) {
                count = info->fix.smem_len - p;
                err = -ENOSPC;
        }

        if (count) {
                char *base_addr;

                base_addr = info->screen_base;
                count -= copy_from_user16(base_addr + p, buf, count);
                *ppos += count;
                err = -EFAULT;
        }
        if (count)
                return count;
        return err;
}

/* ------------------------------------------------------------------------- */

static struct fb_ops epson1355fb_fbops = {
        .owner          = THIS_MODULE,
        .fb_setcolreg   = epson1355fb_setcolreg,
        .fb_pan_display = epson1355fb_pan_display,
        .fb_blank       = epson1355fb_blank,
        .fb_fillrect    = cfb_fillrect,
        .fb_copyarea    = cfb_copyarea,
        .fb_imageblit   = cfb_imageblit,
        .fb_read        = epson1355fb_read,
        .fb_write       = epson1355fb_write,
};

/* ------------------------------------------------------------------------- */

static __init unsigned int get_fb_size(struct fb_info *info)
{
        unsigned int size = 2 * 1024 * 1024;
        char *p = info->screen_base;

        /* the 512k framebuffer is aliased at start + 0x80000 * n */
        fb_writeb(1, p);
        fb_writeb(0, p + 0x80000);
        if (!fb_readb(p))
                size = 512 * 1024;

        fb_writeb(0, p);

        return size;
}

static int epson1355_width_tab[2][4] __initdata =
    { {4, 8, 16, -1}, {9, 12, 16, -1} };
static int epson1355_bpp_tab[8] __initdata = { 1, 2, 4, 8, 15, 16 };

static void __init fetch_hw_state(struct fb_info *info, struct epson1355_par *par)
{
        struct fb_var_screeninfo *var = &info->var;
        struct fb_fix_screeninfo *fix = &info->fix;
        u8 panel, display;
        u16 offset;
        u32 xres, yres;
        u32 xres_virtual, yres_virtual;
        int bpp, lcd_bpp;
        int is_color, is_dual, is_tft;
        int lcd_enabled, crt_enabled;

        fix->type = FB_TYPE_PACKED_PIXELS;

        display = epson1355_read_reg(par, REG_DISPLAY_MODE);
        bpp = epson1355_bpp_tab[(display >> 2) & 7];

        switch (bpp) {
        case 8:
                fix->visual = FB_VISUAL_PSEUDOCOLOR;
                var->bits_per_pixel = 8;
                var->red.offset = var->green.offset = var->blue.offset = 0;
                var->red.length = var->green.length = var->blue.length = 8;
                break;
        case 16:
                /* 5-6-5 RGB */
                fix->visual = FB_VISUAL_TRUECOLOR;
                var->bits_per_pixel = 16;
                var->red.offset = 11;
                var->red.length = 5;
                var->green.offset = 5;
                var->green.length = 6;
                var->blue.offset = 0;
                var->blue.length = 5;
                break;
        default:
                BUG();
        }
        fb_alloc_cmap(&(info->cmap), 256, 0);

        panel = epson1355_read_reg(par, REG_PANEL_TYPE);
        is_color = (panel & 0x04) != 0;
        is_dual = (panel & 0x02) != 0;
        is_tft = (panel & 0x01) != 0;
        crt_enabled = (display & 0x02) != 0;
        lcd_enabled = (display & 0x01) != 0;
        lcd_bpp = epson1355_width_tab[is_tft][(panel >> 4) & 3];

        xres = (epson1355_read_reg(par, REG_HORZ_DISP_WIDTH) + 1) * 8;
        yres = (epson1355_read_reg16(par, REG_VERT_DISP_HEIGHT0) + 1) *
            ((is_dual && !crt_enabled) ? 2 : 1);
        offset = epson1355_read_reg16(par, REG_MEM_ADDR_OFFSET0) & 0x7ff;
        xres_virtual = offset * 16 / bpp;
        yres_virtual = fix->smem_len / (offset * 2);

        var->xres = xres;
        var->yres = yres;
        var->xres_virtual = xres_virtual;
        var->yres_virtual = yres_virtual;
        var->xoffset = var->yoffset = 0;

        fix->line_length = offset * 2;

        fix->xpanstep = 0;      /* no pan yet */
        fix->ypanstep = 1;
        fix->ywrapstep = 0;
        fix->accel = FB_ACCEL_NONE;

        var->grayscale = !is_color;

#ifdef DEBUG
        printk(KERN_INFO
               "epson1355fb: xres=%d, yres=%d, "
               "is_color=%d, is_dual=%d, is_tft=%d\n",
               xres, yres, is_color, is_dual, is_tft);
        printk(KERN_INFO
               "epson1355fb: bpp=%d, lcd_bpp=%d, "
               "crt_enabled=%d, lcd_enabled=%d\n",
               bpp, lcd_bpp, crt_enabled, lcd_enabled);
#endif
}


static void clearfb16(struct fb_info *info)
{
        u16 *dst = (u16 *) info->screen_base;
        unsigned long n = info->fix.smem_len;

        while (n > 1) {
                fb_writew(0, dst);
                dst++, n -= 2;
        }

        if (n)
                fb_writeb(0, dst);
}

static int epson1355fb_remove(struct platform_device *dev)
{
        struct fb_info *info = platform_get_drvdata(dev);
        struct epson1355_par *par = info->par;

        backlight_enable(0);
        if (par) {
                lcd_enable(par, 0);
                if (par && par->reg_addr)
                        iounmap((void *) par->reg_addr);
        }

        if (info) {
                fb_dealloc_cmap(&info->cmap);
                if (info->screen_base)
                        iounmap(info->screen_base);
                framebuffer_release(info);
        }
        release_mem_region(EPSON1355FB_FB_PHYS, EPSON1355FB_FB_LEN);
        release_mem_region(EPSON1355FB_REGS_PHYS, EPSON1355FB_REGS_LEN);
        return 0;
}

int __init epson1355fb_probe(struct platform_device *dev)
{
        struct epson1355_par *default_par;
        struct fb_info *info;
        u8 revision;
        int rc = 0;

        if (!request_mem_region(EPSON1355FB_REGS_PHYS, EPSON1355FB_REGS_LEN, "S1D13505 registers")) {
                printk(KERN_ERR "epson1355fb: unable to reserve "
                       "registers at 0x%0x\n", EPSON1355FB_REGS_PHYS);
                rc = -EBUSY;
                goto bail;
        }

        if (!request_mem_region(EPSON1355FB_FB_PHYS, EPSON1355FB_FB_LEN,
                                "S1D13505 framebuffer")) {
                printk(KERN_ERR "epson1355fb: unable to reserve "
                       "framebuffer at 0x%0x\n", EPSON1355FB_FB_PHYS);
                rc = -EBUSY;
                goto bail;
        }

        info = framebuffer_alloc(sizeof(struct epson1355_par) + sizeof(u32) * 256, &dev->dev);
        if (!info)
                rc = -ENOMEM;
                goto bail;

        default_par = info->par;
        default_par->reg_addr = (unsigned long) ioremap(EPSON1355FB_REGS_PHYS, EPSON1355FB_REGS_LEN);
        if (!default_par->reg_addr) {
                printk(KERN_ERR "epson1355fb: unable to map registers\n");
                rc = -ENOMEM;
                goto bail;
        }
        info->pseudo_palette = (void *)(default_par + 1);

        info->screen_base = ioremap(EPSON1355FB_FB_PHYS, EPSON1355FB_FB_LEN);
        if (!info->screen_base) {
                printk(KERN_ERR "epson1355fb: unable to map framebuffer\n");
                rc = -ENOMEM;
                goto bail;
        }

        revision = epson1355_read_reg(default_par, REG_REVISION_CODE);
        if ((revision >> 2) != 3) {
                printk(KERN_INFO "epson1355fb: epson1355 not found\n");
                rc = -ENODEV;
                goto bail;
        }

        info->fix.mmio_start = EPSON1355FB_REGS_PHYS;
        info->fix.mmio_len = EPSON1355FB_REGS_LEN;
        info->fix.smem_start = EPSON1355FB_FB_PHYS;
        info->fix.smem_len = get_fb_size(info);

        printk(KERN_INFO "epson1355fb: regs mapped at 0x%lx, fb %d KiB mapped at 0x%p\n",
               default_par->reg_addr, info->fix.smem_len / 1024, info->screen_base);

        strcpy(info->fix.id, "S1D13505");
        info->par = default_par;
        info->fbops = &epson1355fb_fbops;
        info->flags = FBINFO_DEFAULT | FBINFO_HWACCEL_YPAN;

        /* we expect the boot loader to have initialized the chip
           with appropriate parameters from which we can determinte
           the flavor of lcd panel attached */
        fetch_hw_state(info, default_par);

        /* turn this puppy on ... */
        clearfb16(info);
        backlight_enable(1);
        lcd_enable(default_par, 1);

        if (register_framebuffer(info) < 0) {
                rc = -EINVAL;
                goto bail;
        }
        /*
         * Our driver data.
         */
        platform_set_drvdata(dev, info);

        printk(KERN_INFO "fb%d: %s frame buffer device\n",
               info->node, info->fix.id);

        return 0;

      bail:
        epson1355fb_remove(dev);
        return rc;
}

static struct platform_driver epson1355fb_driver = {
        .probe  = epson1355fb_probe,
        .remove = epson1355fb_remove,
        .driver = {
                .name   = "epson1355fb",
        },
};

static struct platform_device *epson1355fb_device;

int __init epson1355fb_init(void)
{
        int ret = 0;

        if (fb_get_options("epson1355fb", NULL))
                return -ENODEV;

        ret = platform_driver_register(&epson1355fb_driver);

        if (!ret) {
                epson1355fb_device = platform_device_alloc("epson1355fb", 0);

                if (epson1355fb_device)
                        ret = platform_device_add(epson1355fb_device);
                else
                        ret = -ENOMEM;

                if (ret) {
                        platform_device_put(epson1355fb_device);
                        platform_driver_unregister(&epson1355fb_driver);
                }
        }

        return ret;
}

module_init(epson1355fb_init);
        
#ifdef MODULE
static void __exit epson1355fb_exit(void)
{
        platform_device_unregister(epson1355fb_device);
        platform_driver_unregister(&epson1355fb_driver);
}

/* ------------------------------------------------------------------------- */

module_exit(epson1355fb_exit);
#endif

MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>");
MODULE_DESCRIPTION("Framebuffer driver for Epson S1D13505");
MODULE_LICENSE("GPL");