On Tue, Dec 25, 2012 at 06:26:02PM +0800, Barry Song wrote: > @@ -375,7 +375,12 @@ static void sirfsoc_uart_set_termios(struct uart_port *port, > int threshold_div; > int temp; > > - ioclk_rate = 150000000; > + struct clk *clk = clk_get_sys("io", NULL); > + BUG_ON(IS_ERR(clk)); No. Really, no. Stop using BUG_ON() as some kind of crappy assert(). BUG_ON() takes the entire kernel out when it fails. There's absolutely no need for this what so ever - especially here. Get the clock at probe or port initialization time. Save that pointer. Only give it up when the port is torn down. And treat it as any other clock - prepare and enable it, and disable and unprepare it when you're done with it. And there's no need to use this clk_get_sys() crap in drivers. Add the necessary clkdev entries or deal with it in DT. Absolutely do not use clk_get_sys() in drivers; it's there for *PLATFORM* code to use when there's no other possibility for them and NOT drivers. -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html