Re: [PATCH] serial/imx: enable the clock when we really use the uart port

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, May 02, 2012 at 04:19:30PM +0800, Huang Shijie wrote:
> The current code keeps the clock enabled even when we do not really
> use the uart port. But keep the clock enabled will consume some power.
> 
> In order to save more power, disable the clock when we do not use
> the uart, and enable the clock when we really use the uart port.
> 
> Signed-off-by: Huang Shijie <b32955@freescale.com>

This conflicts with my series converting i.MX to the common clock
framework. Please lets delay this until this has been merged.

Sascha

> ---
>  drivers/tty/serial/imx.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index e7fecee..f5dcdf6 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -694,6 +694,8 @@ static int imx_startup(struct uart_port *port)
>  	int retval;
>  	unsigned long flags, temp;
>  
> +	clk_prepare_enable(sport->clk);
> +
>  	imx_setup_ufcr(sport, 0);
>  
>  	/* disable the DREN bit (Data Ready interrupt enable) before
> @@ -877,6 +879,8 @@ static void imx_shutdown(struct uart_port *port)
>  		temp &= ~(UCR1_IREN);
>  
>  	writel(temp, sport->port.membase + UCR1);
> +
> +	clk_disable_unprepare(sport->clk);
>  }
>  
>  static void
> @@ -1526,6 +1530,7 @@ static int serial_imx_probe(struct platform_device *pdev)
>  		goto deinit;
>  	platform_set_drvdata(pdev, &sport->port);
>  
> +	clk_disable_unprepare(sport->clk);
>  	return 0;
>  deinit:
>  	if (pdata && pdata->exit)
> @@ -1552,7 +1557,6 @@ static int serial_imx_remove(struct platform_device *pdev)
>  
>  	if (sport) {
>  		uart_remove_one_port(&imx_reg, &sport->port);
> -		clk_disable_unprepare(sport->clk);
>  		clk_put(sport->clk);
>  	}
>  
> -- 
> 1.7.3.2
> 
> 
> 

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