gpmc_calc_divider
div = gpmc_calc_divider(sync_clk);
gpmc_t->sync_clk = gpmc_calc_divider(dev_t->clk) *
if (gpmc_calc_divider(gpmc_t->sync_clk) != 1)
div = gpmc_calc_divider(t->sync_clk);
extern int gpmc_calc_divider(unsigned int sync_clk);