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SubjectRe: [PATCH] serial: samsung: move clock deactivation below uart registration
Date
Hi Greg,

just wanted to ask about the state of this patch. I can see it in your branch
named "fixes" [0] but it seems it hasn't made its way into the kernel neither
during the 3.13-rcs or with your 3.14-pull [1].


Thanks
Heiko


[0] https://git.kernel.org/cgit/linux/kernel/git/gregkh/tty.git/log/?h=fixes
[1]
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bcee63488ece9a0fca8be19951428a7b41001e66


Am Donnerstag, 5. Dezember 2013, 00:54:38 schrieb Heiko Stübner:
> Commit 60e93575476f (serial: samsung: enable clock before clearing pending
> interrupts during init) added handling of the controller clock during init.
>
> On most systems this clock is also one of the baud_clock sources and
> possibly used by the earlycon and thus already enabled by the bootloader.
>
> Therefore a gap exists between s3c24xx_serial_init_port disabling the
> clock and an attached console reenabling it, making the transition from
> earlycon to regular console possibly hang the system - as seen on my
> S3C2442 based Freerunner today.
>
> Therefore move the disabling of the clock from s3c24xx_serial_init_port
> below the uart port registration, effectively creating an overlap and
> keeping the clock running non-stop if the console wants to grab this port.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
> drivers/tty/serial/samsung.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> index c1af04d..9cd706d 100644
> --- a/drivers/tty/serial/samsung.c
> +++ b/drivers/tty/serial/samsung.c
> @@ -1209,7 +1209,6 @@ static int s3c24xx_serial_init_port(struct
> s3c24xx_uart_port *ourport,
>
> /* reset the fifos (and setup the uart) */
> s3c24xx_serial_resetport(port, cfg);
> - clk_disable_unprepare(ourport->clk);
> return 0;
> }
>
> @@ -1287,6 +1286,13 @@ static int s3c24xx_serial_probe(struct
> platform_device *pdev) uart_add_one_port(&s3c24xx_uart_drv,
> &ourport->port);
> platform_set_drvdata(pdev, &ourport->port);
>
> + /*
> + * Deactivate the clock enabled in s3c24xx_serial_init_port here,
> + * so that a potential re-enablement through the pm-callback overlaps
> + * and keeps the clock enabled in this case.
> + */
> + clk_disable_unprepare(ourport->clk);
> +
> #ifdef CONFIG_SAMSUNG_CLOCK
> ret = device_create_file(&pdev->dev, &dev_attr_clock_source);
> if (ret < 0)

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