| Message ID | 1370311173-15019-1-git-send-email-b32955@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 04, 2013 at 09:59:33AM +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@freescale.com> Running linux-next 20130607, I just found that the serial console stops working due to this patch. I think the clocks need to be enabled for console as well. Shawn > --- > v1 --> v2: > check the return value of clk_prepare_enable(). > --- > drivers/tty/serial/imx.c | 17 ++++++++++++++--- > 1 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index 72bc1db..7cc4810 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -699,6 +699,14 @@ static int imx_startup(struct uart_port *port) > int retval; > unsigned long flags, temp; > > + retval = clk_prepare_enable(sport->clk_per); > + if (retval) > + goto error_out1; > + > + retval = clk_prepare_enable(sport->clk_ipg); > + if (retval) > + goto error_out1; > + > imx_setup_ufcr(sport, 0); > > /* disable the DREN bit (Data Ready interrupt enable) before > @@ -884,6 +892,9 @@ static void imx_shutdown(struct uart_port *port) > > writel(temp, sport->port.membase + UCR1); > spin_unlock_irqrestore(&sport->port.lock, flags); > + > + clk_disable_unprepare(sport->clk_per); > + clk_disable_unprepare(sport->clk_ipg); > } > > static void > @@ -1557,6 +1568,9 @@ static int serial_imx_probe(struct platform_device *pdev) > goto deinit; > platform_set_drvdata(pdev, sport); > > + clk_disable_unprepare(sport->clk_per); > + clk_disable_unprepare(sport->clk_ipg); > + > return 0; > deinit: > if (pdata && pdata->exit) > @@ -1578,9 +1592,6 @@ static int serial_imx_remove(struct platform_device *pdev) > > uart_remove_one_port(&imx_reg, &sport->port); > > - clk_disable_unprepare(sport->clk_per); > - clk_disable_unprepare(sport->clk_ipg); > - > if (pdata && pdata->exit) > pdata->exit(pdev); > > -- > 1.7.1 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
? 2013?06?08? 14:01, Shawn Guo ??: > Running linux-next 20130607, I just found that the serial console stops > working due to this patch. I think the clocks need to be enabled for > console as well. could you tell me the board? i tested on imx6q-sabreauto boards, the console is ok. thanks Huang Shijie
On Sat, Jun 08, 2013 at 02:22:39PM +0800, Huang Shijie wrote: > ? 2013?06?08? 14:01, Shawn Guo ??: > >Running linux-next 20130607, I just found that the serial console stops > >working due to this patch. I think the clocks need to be enabled for > >console as well. > could you tell me the board? > i tested on imx6q-sabreauto boards, the console is ok. imx6q-sabresd Shawn
On Sat, Jun 08, 2013 at 02:22:39PM +0800, Huang Shijie wrote: > ? 2013?06?08? 14:01, Shawn Guo ??: >> Running linux-next 20130607, I just found that the serial console stops >> working due to this patch. I think the clocks need to be enabled for >> console as well. > could you tell me the board? > i tested on imx6q-sabreauto boards, the console is ok. Take a look at amba-pl011.c to see how to deal with the console and clk API correctly in serial drivers.
> On Sat, Jun 08, 2013 at 02:22:39PM +0800, Huang Shijie wrote: > > ? 2013?06?08? 14:01, Shawn Guo ??: > > >Running linux-next 20130607, I just found that the serial console stops > > >working due to this patch. I think the clocks need to be enabled for > > >console as well. > > could you tell me the board? > > i tested on imx6q-sabreauto boards, the console is ok. > > imx6q-sabresd I confirm that console not work correct after this patch on the i.MX27 PCM038 board. ---
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 72bc1db..7cc4810 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -699,6 +699,14 @@ static int imx_startup(struct uart_port *port) int retval; unsigned long flags, temp; + retval = clk_prepare_enable(sport->clk_per); + if (retval) + goto error_out1; + + retval = clk_prepare_enable(sport->clk_ipg); + if (retval) + goto error_out1; + imx_setup_ufcr(sport, 0); /* disable the DREN bit (Data Ready interrupt enable) before @@ -884,6 +892,9 @@ static void imx_shutdown(struct uart_port *port) writel(temp, sport->port.membase + UCR1); spin_unlock_irqrestore(&sport->port.lock, flags); + + clk_disable_unprepare(sport->clk_per); + clk_disable_unprepare(sport->clk_ipg); } static void @@ -1557,6 +1568,9 @@ static int serial_imx_probe(struct platform_device *pdev) goto deinit; platform_set_drvdata(pdev, sport); + clk_disable_unprepare(sport->clk_per); + clk_disable_unprepare(sport->clk_ipg); + return 0; deinit: if (pdata && pdata->exit) @@ -1578,9 +1592,6 @@ static int serial_imx_remove(struct platform_device *pdev) uart_remove_one_port(&imx_reg, &sport->port); - clk_disable_unprepare(sport->clk_per); - clk_disable_unprepare(sport->clk_ipg); - if (pdata && pdata->exit) pdata->exit(pdev);
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@freescale.com> --- v1 --> v2: check the return value of clk_prepare_enable(). --- drivers/tty/serial/imx.c | 17 ++++++++++++++--- 1 files changed, 14 insertions(+), 3 deletions(-)