[uGFX BLIT API for RA8875]

Hi,

I am using uGFX on Raspberry Pi for displaying graphics on RA8875 based display. Raspberry Pi communicates with display using 4-wire SPI. I am porting the gdisp_lld_blit_area() driver API using  BTE (block transfer engine) available in RA8875. I am using write-BTE operation mode with ROP (raster operation) as destination = source.

Here is my sample code with this post. screenshots of expected and actual output is also attached. any suggestions/recommendations would be helpful.

#if 1//GDISP_HARDWARE_BITFILLS || defined(__DOXYGEN__)

// macros
#define RA8875_MRWC             0x02
#define RA8875_BECR0            0x50
#define RA8875_BECR1            0x51
#define RA8875_HDBE0            0x58
#define RA8875_HDBE1            0x59
#define RA8875_VDBE0            0x5A
#define RA8875_VDBE1            0x5B
#define RA8875_BEWR0            0x5C
#define RA8875_BEWR1            0x5D
#define RA8875_BEHR0            0x5E
#define RA8875_BEHR1            0x5F
#define RA8875_BGCR0            0x60  // = red, next 2 are green and blue
#define RA8875_FGCR0            0x63  // = red, next 2 are green and blue
#define RA8875_MWCR0            0x40
#define RA8875_MWCR0_GFXMODE    0x00
#define RA8875_MWCR0_TXTMODE    0x80
#define RA8875_MWCR1            0x41
#define RA8875_CURH0            0x46
#define RA8875_CURH1            0x47
#define RA8875_CURV0            0x48
#define RA8875_CURV1            0x49

/**
 * @brief   Function to draw bitmap
 * @pre        GDISP_HARDWARE_BITFILLS is GFXON
 *
 * @param[in]    g                The driver structure
 * @param[in]    destX,destY        The area position
 * @param[in]    width,height    The area size i.e. width and height
 * @param[in]    fgColor            The foreground color
 * @param[in]    bgColor            The background color
 * @param[in]    bits            The pointer to the bitmap
 *
 * @note        The parameter variables must not be altered by the driver.
*/
static GFXINLINE void drawBitmap(GDisplay *g,
        gI16 destX, gI16 destY,
        gI16 width, gI16 height,
        gU16 fgColor, gU16 bgColor,
        gU8* bits)
{
    // locals
    gI32 h = 0, w = 0;
    gU8 temp = 0, tempbkp = 0;
    static gU32 cnt = 0;

    /*printf("\ndraw bitmap: x=%d y=%d w=%d h=%d "
            "x1=%d y1=%d x2=%d y2=%d "
            "fg=%x bg=%x cnt=%d",
            destX, destY, width, height,
            g->p.x1, g->p.y1, g->p.x2, g->p.y2,
            fgColor, bgColor, ++cnt);
            */

    // always enter graphics mode for BTE operations
    write_index(g, RA8875_MWCR0);
    temp = (gU8)read_data(g);
    tempbkp = temp;
    temp &= ~RA8875_MWCR0_TXTMODE;
    write_data(g, temp);

    // set destination, width and height
    write_reg16(g, RA8875_HDBE0, destX);
    write_reg16(g, RA8875_VDBE0, destY);
    write_reg16(g, RA8875_BEWR0, width);  // image width
    write_reg16(g, RA8875_BEHR0, height); // image height

    // set colors
    writeColorReg(g, RA8875_BGCR0, bgColor);
    writeColorReg(g, RA8875_FGCR0, fgColor);

    // set cursor position
    write_reg16(g, RA8875_CURH0, destX);
    write_reg16(g, RA8875_CURV0, destY);

    // BTE operation mode
    // Bits [3:0] 1000b is color expansion 0000b is write-BTE
    // Bits [7:4] 0111b is start bit position for color expansion
    // Bits [7:4] 1100b is S=D for write-BTE
    //write_reg8(g, RA8875_BECR1, (0x07 << 4) | 0x08);  // start bit = 7, operation = Color Expansion
    write_reg8(g, RA8875_BECR1, 0xC0); // write-BTE with ROP as S=D

    // draw in block mode 0x80, in linear mode 0xE0
    write_reg8(g, RA8875_BECR0, 0x80);  // begin operation

    // write command
    write_index(g, RA8875_MRWC);

    // write data
    for (h = 0; h < height; h++)
    {
        //printf("\nh=%d -- ", h);
        for (w = 0; w < width; w += 1)
        {
            //printf("%u ", *bits);
            //usleep(1000);
            write_data(g, *bits++);
        }
    }

    // set text mode NOTE: this may not be needed to
    write_index(g, RA8875_MWCR0);
    //tempbkp = (gU8)read_data(g);
    //tempbkp |= RA8875_MWCR0_TXTMODE; // Set bit 7
    write_data(g, tempbkp);

    //return from function
    return;
}

/**
 * @brief   Fill an area using a bitmap
 * @pre        GDISP_HARDWARE_BITFILLS is GFXON
 *
 * @param[in]    g                The driver structure
 * @param[in]    g->p.x,g->p.y    The area position
 * @param[in]    g->p.cx,g->p.cy    The area size
 * @param[in]    g->p.x1,g->p.y1    The starting position in the bitmap
 * @param[in]    g->p.x2            The width of a bitmap line
 * @param[in]    g->p.ptr        The pointer to the bitmap
 *
 * @note        The parameter variables must not be altered by the driver.
 */
LLDSPEC    void gdisp_lld_blit_area(GDisplay *g)
{
    if((void *)0 == g)
    {
        //invalid pointer, return from function
        return;
    }

    // draw the bitmap
    // 0xFFFF is white
    // 0x0000 is black
    drawBitmap(g, g->p.x, g->p.y, g->p.cx*2, g->p.cy,
            g->p.color, 0x0000, g->p.ptr);

    //return from function
    return;
}
#endif /* use BLIT */

expected-output.bmp

blit.c