* Re: [PATCH 11/15] serial: mxs-auart: Use clk_prepare_enable/clk_disable_unprepare
2012-05-25 23:14 ` [PATCH 11/15] serial: mxs-auart: Use clk_prepare_enable/clk_disable_unprepare Fabio Estevam
@ 2012-06-11 2:36 ` Shawn Guo
0 siblings, 0 replies; 2+ messages in thread
From: Shawn Guo @ 2012-06-11 2:36 UTC (permalink / raw)
To: Fabio Estevam
Cc: kernel, Fabio Estevam, Alan Cox, Greg Kroah-Hartman, linux-serial
On Fri, May 25, 2012 at 08:14:52PM -0300, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
>
> Prepare the clock before enabling it.
>
> Cc: Alan Cox <alan@linux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: <linux-serial@vger.kernel.org>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> drivers/tty/serial/mxs-auart.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
> index ec56d83..c109642 100644
> --- a/drivers/tty/serial/mxs-auart.c
> +++ b/drivers/tty/serial/mxs-auart.c
> @@ -552,7 +552,7 @@ auart_console_write(struct console *co, const char *str, unsigned int count)
> s = auart_port[co->index];
> port = &s->port;
>
> - clk_enable(s->clk);
> + clk_prepare_enable(s->clk);
>
> /* First save the CR then disable the interrupts */
> old_ctrl2 = readl(port->membase + AUART_CTRL2);
> @@ -578,7 +578,7 @@ auart_console_write(struct console *co, const char *str, unsigned int count)
> writel(old_ctrl0, port->membase + AUART_CTRL0);
> writel(old_ctrl2, port->membase + AUART_CTRL2);
>
> - clk_disable(s->clk);
> + clk_disable_unprepare(s->clk);
> }
>
> static void __init
> --
> 1.7.1
>
No, clk_prepare() should not be called in auart_console_write() which
is an atomic context. However it reminds me that auart_console_setup()
needs a fix as below.
Regards,
Shawn
--8<---
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index ec56d83..a3bb06b 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -638,18 +638,16 @@ auart_console_setup(struct console *co, char *options)
if (!s)
return -ENODEV;
- clk_prepare_enable(s->clk);
+ clk_prepare(s->clk);
+ if (ret)
+ return ret;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
auart_console_get_options(&s->port, &baud, &parity, &bits);
- ret = uart_set_options(&s->port, co, baud, parity, bits, flow);
-
- clk_disable_unprepare(s->clk);
-
- return ret;
+ return uart_set_options(&s->port, co, baud, parity, bits, flow);
}
static struct console auart_console = {
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