Re: [PATCH 3/4] tty: serial: 8250_mtk: use pm_runtime callbacks for enabling

[Matthias Brugger]

2015-05-04 14:06 GMT+02:00 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>:
> On Mon, May 04, 2015 at 01:05:27PM +0200, Matthias Brugger wrote:
>> 2015-04-27 8:49 GMT+02:00 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>:
>> > The pm_runtime callbacks already enable and disable the device.
>> > Use them in probe() and remove() instead of duplicating the
>> > code. This allows us to concentrate more code for enabling/disabling
>> > the UART in a single place.
>> >
>> > Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
>> > ---
>> >  drivers/tty/serial/8250/8250_mtk.c | 69 ++++++++++++++++++++------------------
>> >  1 file changed, 36 insertions(+), 33 deletions(-)
>> >
>> > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
>> > index bcfaa8dc..2f28bd0 100644
>> > --- a/drivers/tty/serial/8250/8250_mtk.c
>> > +++ b/drivers/tty/serial/8250/8250_mtk.c
>> > @@ -115,6 +115,29 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
>> >                 tty_termios_encode_baud_rate(termios, baud, baud);
>> >  }
>> >
>> > +static int mtk8250_runtime_suspend(struct device *dev)
>> > +{
>> > +       struct mtk8250_data *data = dev_get_drvdata(dev);
>> > +
>> > +       clk_disable_unprepare(data->uart_clk);
>> > +
>> > +       return 0;
>> > +}
>> > +
>> > +static int mtk8250_runtime_resume(struct device *dev)
>> > +{
>> > +       struct mtk8250_data *data = dev_get_drvdata(dev);
>> > +       int err;
>> > +
>> > +       err = clk_prepare_enable(data->uart_clk);
>> > +       if (err) {
>> > +               dev_warn(dev, "Can't enable clock\n");
>> > +               return err;
>> > +       }
>> > +
>> > +       return 0;
>> > +}
>> > +
>> >  static void
>> >  mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
>> >  {
>> > @@ -130,19 +153,12 @@ mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
>> >  static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
>> >                            struct mtk8250_data *data)
>> >  {
>> > -       int err;
>> > -
>> >         data->uart_clk = devm_clk_get(&pdev->dev, NULL);
>> >         if (IS_ERR(data->uart_clk)) {
>> >                 dev_warn(&pdev->dev, "Can't get uart clock\n");
>> >                 return PTR_ERR(data->uart_clk);
>> >         }
>> >
>> > -       err = clk_prepare_enable(data->uart_clk);
>> > -       if (err) {
>> > -               dev_warn(&pdev->dev, "Can't prepare clock\n");
>> > -               return err;
>> > -       }
>> >         p->uartclk = clk_get_rate(data->uart_clk);
>> >
>> >         return 0;
>> > @@ -193,14 +209,18 @@ static int mtk8250_probe(struct platform_device *pdev)
>> >         writel(0x0, uart.port.membase +
>> >                         (MTK_UART_RATE_FIX << uart.port.regshift));
>> >
>> > -       data->line = serial8250_register_8250_port(&uart);
>> > -       if (data->line < 0)
>> > -               return data->line;
>> > -
>> >         platform_set_drvdata(pdev, data);
>> >
>> > -       pm_runtime_set_active(&pdev->dev);
>> >         pm_runtime_enable(&pdev->dev);
>> > +       if (!pm_runtime_enabled(&pdev->dev)) {
>> > +               err = mtk8250_runtime_resume(&pdev->dev);
>> > +               if (err)
>> > +                       return err;
>> > +       }
>> > +
>> > +       data->line = serial8250_register_8250_port(&uart);
>> > +       if (data->line < 0)
>> > +               return data->line;
>>
>> Why do you delete pm_runtime_set_active here?
>
> pm_runtime_set_active() communicates the initial state of the device to
> the pm core. Previously the driver activated the device manually by
> directly calling clk_prepare_enable(). Since this manual enabling of
> the clock is removed in this patch, the device is no longer active,
> hence pm_runtime_set_active() has to be removed.

Sounds resonable.
Acked-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>

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