/*
 * SSD0303 OLED controller with OSRAM Pictiva 96x16 display.
 *
 * Copyright (c) 2006-2007 CodeSourcery.
 * Written by Paul Brook
 *
 * This code is licenced under the GPL.
 */

/* The controller can support a variety of different displays, but we only
   implement one.  Most of the commends relating to brightness and geometry
   setup are ignored. */
#include "hw.h"
#include "i2c.h"
#include "console.h"

//#define DEBUG_SSD0303 1

#ifdef DEBUG_SSD0303
#define DPRINTF(fmt, args...) \
do { printf("ssd0303: " fmt , ##args); } while (0)
#define BADF(fmt, args...) \
do { fprintf(stderr, "ssd0303: error: " fmt , ##args); exit(1);} while (0)
#else
#define DPRINTF(fmt, args...) do {} while(0)
#define BADF(fmt, args...) \
do { fprintf(stderr, "ssd0303: error: " fmt , ##args);} while (0)
#endif

/* Scaling factor for pixels.  */
#define MAGNIFY 4

enum ssd0303_mode
{
    SSD0303_IDLE,
    SSD0303_DATA,
    SSD0303_CMD
};

enum ssd0303_cmd {
    SSD0303_CMD_NONE,
    SSD0303_CMD_SKIP1
};

typedef struct {
    i2c_slave i2c;
    DisplayState *ds;
    int row;
    int col;
    int start_line;
    int mirror;
    int flash;
    int enabled;
    int inverse;
    int redraw;
    enum ssd0303_mode mode;
    enum ssd0303_cmd cmd_state;
    uint8_t framebuffer[132*8];
} ssd0303_state;

static int ssd0303_recv(i2c_slave *i2c)
{
    BADF("Reads not implemented\n");
    return -1;
}

static int ssd0303_send(i2c_slave *i2c, uint8_t data)
{
    ssd0303_state *s = (ssd0303_state *)i2c;
    enum ssd0303_cmd old_cmd_state;
    switch (s->mode) {
    case SSD0303_IDLE:
        DPRINTF("byte 0x%02x\n", data);
        if (data == 0x80)
            s->mode = SSD0303_CMD;
        else if (data == 0x40)
            s->mode = SSD0303_DATA;
        else
            BADF("Unexpected byte 0x%x\n", data);
        break;
    case SSD0303_DATA:
        DPRINTF("data 0x%02x\n", data);
        if (s->col < 132) {
            s->framebuffer[s->col + s->row * 132] = data;
            s->col++;
            s->redraw = 1;
        }
        break;
    case SSD0303_CMD:
        old_cmd_state = s->cmd_state;
        s->cmd_state = SSD0303_CMD_NONE;
        switch (old_cmd_state) {
        case SSD0303_CMD_NONE:
            DPRINTF("cmd 0x%02x\n", data);
            s->mode = SSD0303_IDLE;
            switch (data) {
            case 0x00 ... 0x0f: /* Set lower colum address.  */
                s->col = (s->col & 0xf0) | (data & 0xf);
                break;
            case 0x10 ... 0x20: /* Set higher column address.  */
                s->col = (s->col & 0x0f) | ((data & 0xf) << 4);
                break;
            case 0x40 ... 0x7f: /* Set start line.  */
                s->start_line = 0;
                break;
            case 0x81: /* Set contrast (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xa0: /* Mirror off.  */
                s->mirror = 0;
                break;
            case 0xa1: /* Mirror off.  */
                s->mirror = 1;
                break;
            case 0xa4: /* Entire display off.  */
                s->flash = 0;
                break;
            case 0xa5: /* Entire display on.  */
                s->flash = 1;
                break;
            case 0xa6: /* Inverse off.  */
                s->inverse = 0;
                break;
            case 0xa7: /* Inverse on.  */
                s->inverse = 1;
                break;
            case 0xa8: /* Set multipled ratio (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xad: /* DC-DC power control.  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xae: /* Display off.  */
                s->enabled = 0;
                break;
            case 0xaf: /* Display on.  */
                s->enabled = 1;
                break;
            case 0xb0 ... 0xbf: /* Set Page address.  */
                s->row = data & 7;
                break;
            case 0xc0 ... 0xc8: /* Set COM output direction (Ignored).  */
                break;
            case 0xd3: /* Set display offset (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xd5: /* Set display clock (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xd8: /* Set color and power mode (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xd9: /* Set pre-charge period (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xda: /* Set COM pin configuration (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xdb: /* Set VCOM dselect level (Ignored).  */
                s->cmd_state = SSD0303_CMD_SKIP1;
                break;
            case 0xe3: /* no-op.  */
                break;
            default:
                BADF("Unknown command: 0x%x\n", data);
            }
            break;
        case SSD0303_CMD_SKIP1:
            DPRINTF("skip 0x%02x\n", data);
            break;
        }
        break;
    }
    return 0;
}

static void ssd0303_event(i2c_slave *i2c, enum i2c_event event)
{
    ssd0303_state *s = (ssd0303_state *)i2c;
    switch (event) {
    case I2C_FINISH:
        s->mode = SSD0303_IDLE;
        break;
    case I2C_START_RECV:
    case I2C_START_SEND:
    case I2C_NACK:
        /* Nothing to do.  */
        break;
    }
}

static void ssd0303_update_display(void *opaque)
{
    ssd0303_state *s = (ssd0303_state *)opaque;
    uint8_t *dest;
    uint8_t *src;
    int x;
    int y;
    int line;
    char *colors[2];
    char colortab[MAGNIFY * 8];
    int dest_width;
    uint8_t mask;

    if (s->redraw) {
        switch (s->ds->depth) {
        case 0:
            return;
        case 15:
            dest_width = 2;
            break;
        case 16:
            dest_width = 2;
            break;
        case 24:
            dest_width = 3;
            break;
        case 32:
            dest_width = 4;
            break;
        default:
            BADF("Bad color depth\n");
            return;
        }
        dest_width *= MAGNIFY;
        memset(colortab, 0xff, dest_width);
        memset(colortab + dest_width, 0, dest_width);
        if (s->flash) {
            colors[0] = colortab;
            colors[1] = colortab;
        } else if (s->inverse) {
            colors[0] = colortab;
            colors[1] = colortab + dest_width;
        } else {
            colors[0] = colortab + dest_width;
            colors[1] = colortab;
        }
        dest = s->ds->data;
        for (y = 0; y < 16; y++) {
            line = (y + s->start_line) & 63;
            src = s->framebuffer + 132 * (line >> 3) + 36;
            mask = 1 << (line & 7);
            for (x = 0; x < 96; x++) {
                memcpy(dest, colors[(*src & mask) != 0], dest_width);
                dest += dest_width;
                src++;
            }
            for (x = 1; x < MAGNIFY; x++) {
                memcpy(dest, dest - dest_width * 96, dest_width * 96);
                dest += dest_width * 96;
            }
        }
    }
    dpy_update(s->ds, 0, 0, 96 * MAGNIFY, 16 * MAGNIFY);
}

static void ssd0303_invalidate_display(void * opaque)
{
    ssd0303_state *s = (ssd0303_state *)opaque;
    s->redraw = 1;
}

void ssd0303_init(DisplayState *ds, i2c_bus *bus, int address)
{
    ssd0303_state *s;

    s = (ssd0303_state *)i2c_slave_init(bus, address, sizeof(ssd0303_state));
    s->ds = ds;
    s->i2c.event = ssd0303_event;
    s->i2c.recv = ssd0303_recv;
    s->i2c.send = ssd0303_send;
    graphic_console_init(ds, ssd0303_update_display, ssd0303_invalidate_display,
                         NULL, NULL, s);
    dpy_resize(s->ds, 96 * MAGNIFY, 16 * MAGNIFY);
}