[PATCH] serial: imx: enable the clocks only when the uart is used

[Russell King - ARM Linux]

On Mon, Jun 03, 2013 at 03:42:11PM +0800, Huang Shijie wrote:
> Current code opens the clocks when the uart driver is probed.
> This will wastes some power if several uarts are enabled, but not really
> used.
> 
> So close these clocks for uart, and enable the clocks only when
> the uart is used.
> 
> Signed-off-by: Huang Shijie <b32955 at freescale.com>
> ---
>  drivers/tty/serial/imx.c |   12 +++++++++---
>  1 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 72bc1db..5705fc8 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -699,6 +699,9 @@ static int imx_startup(struct uart_port *port)
>  	int retval;
>  	unsigned long flags, temp;
>  
> +	clk_prepare_enable(sport->clk_per);
> +	clk_prepare_enable(sport->clk_ipg);

You should check the return value.  I've a good mind to mark these
functions with __must_check...