AM1808 - 9-bits per word not supported on spidev

Hi,

I'm working on a AM1808-based custom board which has LCD interface.
I've ported the code from da850 evm (sdk_5_03_02_00).
The LCD controller is ILI9340 and must be initialized via a SPI port, 9 bits per word.
I want to use SPI1_SCS[2] to address it.
So I've adapted the following files

arch/arm/mach-davinci/board-da850-k5.c
arch/arm/configs/da850.c
arch/arm/mach-davinci/include/mach/mux.h

and now the spi_board_info struct it looks like this

static struct spi_board_info da850_k5_spi_info[] = {
 [0] = {
  .modalias  = "m25p80",
  .platform_data  = &da850_k5_spiflash_data,
  .controller_data = &da850_k5_spiflash_cfg,
  .mode   = SPI_MODE_0,
  .max_speed_hz  = 30000000,
  .bus_num  = 1,
  .chip_select  = 0,
 },
 [1] = {
  .modalias  = "spidev",
  .mode   = SPI_MODE_0,
  .max_speed_hz  = 1000000,
  .bus_num  = 1,
  .chip_select  = 2,
 },
};

The following user space program allows me to interact with the LCD

int main(int argc, char *argv[])
{
  int fd;
  uint8_t mode = SPI_MODE_0;
  uint8_t bits = 16;
  uint32_t speed = 1000000;
  uint16_t delay = 50;
  uint16_t testdata = 0xaa55;

  fd = open("/dev/spidev1.2", O_RDWR);
  ioctl(fd, SPI_IOC_WR_MODE, &mode);
  ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
  ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);

  write(fd, &testdata, 2);

  close(fd);
  return 0;
}

This program works good, because on the oscilloscope I see the correct waveform.
Now the problem is that really I need 9 bits per word, not 16! (Infact this is a very strange device! the MSB of the word tells if the value is a command or a data)

However it seems that the SPI_IOC_WR_BITS_PER_WORD ioctl accepts only 8 or 16. Can you confirm it ?

So, what can I do ? Do I have to modify drivers/spi/spi.c ???????