/* write field of ipu registers, without affecting other bits. */
void ipu_write(int32_t ipu_index, uint32_t ID_addr, uint32_t data)
/* write field of ipu registers, without affecting other bits. */
void ipu_write(int32_t ipu_index, uint32_t ID_addr, uint32_t data)
{
    ID_addr += REGS_IPU_BASE(ipu_index);
    writel(data, ID_addr);
}