LCD: putrun or putarea?

There is LCDDEVIO_PUTAREA and LCDDEVIO_PUTRUN IOCTL that could be called on an LCD device, like /dev/lcd0, bubbling down to _putarea and _putrun implemented in the low-level LCD driver, like ILI9341.

_putrun could be used as _putarea’s fallback when _putarea is not implemented.

Input parameters of _putarea and their constraints:

• row_start ; assert(0 <= row_start < yres)
• row_end ; assert(row_start <= row_end < yres)
• col_start ; assert(0 <= col_start < xres)
• col_end ; assert(col_start <= col_end < xres)

Input parameters of _putrun and their constraints:

• row ; assert(0 <= row < yres)
• col ; assert(0 <= col < xres)
• npixels ; assert(1 <= npixels <= xres - col)

_putrun fallback implemented with _putarea:

col = col_start;
npixels = col_end - col_start + 1;

for (row = row_start; row <= row_end; row++) {
    _putrun(lcd_dev, row, col, buffer, npixels);
}