sh_clk_write
sh_clk_write(value, clk);
sh_clk_write(sh_clk_read(clk) & ~CPG_CKSTP_BIT, clk);
sh_clk_write(val, clk);
sh_clk_write(value | (i << clk->src_shift), clk);
sh_clk_write(value, clk);
sh_clk_write(sh_clk_read(clk) & ~(1 << clk->enable_bit), clk);
sh_clk_write(sh_clk_read(clk) | (1 << clk->enable_bit), clk);