Am Freitag, den 26.10.2012, 11:03 +0300 schrieb Felipe Balbi:
> Hi,
>
> On Fri, Oct 26, 2012 at 09:55:30AM +0200, Tim Niemeyer wrote:
> > Adds support for configuring the omap-gpio driver use autosuspend for
> > runtime power management. This can reduce the latency in using it by
> > not suspending the device immediately on idle. If another access takes
> > place before the autosuspend timeout (2 secs), the call to resume the
> > device can return immediately saving some save/ restore cycles.
> >
> > I use a gpio to monitor a spi transfer which occurs every 250µs. The
> > suspend overhead is to high, so almost every second transfer is lost.
> > This patch fixes that.
> >
> > Signed-off-by: Tim Niemeyer <tim.nieme...@corscience.de>
> > ---
> > drivers/gpio/gpio-omap.c | 23 ++++++++++++++++++-----
> > 1 files changed, 18 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> > index 94cbc84..92f48cb 100644
> > --- a/drivers/gpio/gpio-omap.c
> > +++ b/drivers/gpio/gpio-omap.c
> > @@ -31,6 +31,7 @@
> > #include <asm/mach/irq.h>
> >
> > #define OFF_MODE 1
> > +#define GPIO_AUTOSUSPEND_TIMEOUT 2000
> >
> > static LIST_HEAD(omap_gpio_list);
> >
> > @@ -628,8 +629,10 @@ static void omap_gpio_free(struct gpio_chip *chip,
> > unsigned offset)
> > * If this is the last gpio to be freed in the bank,
> > * disable the bank module.
> > */
> > - if (!bank->mod_usage)
> > - pm_runtime_put(bank->dev);
> > + if (!bank->mod_usage) {
>
> while at that I would drop this bank->mod_usage nonsense and let
> power core handle reference counting.
I looked at it, but i'm unsure about the GPIO_MOD_CTRL_BIT. The
bank->mod_usage counter prevents omap_gpio_free() to disable the hole
bank while another gpio is still in use.
> > + pm_runtime_mark_last_busy(bank->dev);
> > + pm_runtime_put_autosuspend(bank->dev);
> > + }
> > }
> >
> > /*
> > @@ -715,7 +718,8 @@ static void gpio_irq_handler(unsigned int irq, struct
> > irq_desc *desc)
> > exit:
> > if (!unmasked)
> > chained_irq_exit(chip, desc);
> > - pm_runtime_put(bank->dev);
> > + pm_runtime_mark_last_busy(bank->dev);
> > + pm_runtime_put_autosuspend(bank->dev);
> > }
> >
> > static void gpio_irq_shutdown(struct irq_data *d)
> > @@ -1132,6 +1136,8 @@ static int __devinit omap_gpio_probe(struct
> > platform_device *pdev)
> >
> > platform_set_drvdata(pdev, bank);
> >
> > + pm_runtime_use_autosuspend(bank->dev);
> > + pm_runtime_set_autosuspend_delay(bank->dev, GPIO_AUTOSUSPEND_TIMEOUT);
> > pm_runtime_enable(bank->dev);
> > pm_runtime_irq_safe(bank->dev);
> > pm_runtime_get_sync(bank->dev);
> > @@ -1146,7 +1152,8 @@ static int __devinit omap_gpio_probe(struct
> > platform_device *pdev)
> > if (bank->loses_context)
> > bank->get_context_loss_count = pdata->get_context_loss_count;
> >
> > - pm_runtime_put(bank->dev);
> > + pm_runtime_mark_last_busy(bank->dev);
> > + pm_runtime_put_autosuspend(bank->dev);
> >
> > list_add_tail(&bank->node, &omap_gpio_list);
> >
> > @@ -1333,7 +1340,13 @@ void omap2_gpio_prepare_for_idle(int pwr_mode)
> >
> > bank->power_mode = pwr_mode;
> >
> > - pm_runtime_put_sync_suspend(bank->dev);
> > + /* direct pm_runtime on pwroff */
> > + if (pwr_mode)
>
> you also need braces here.
Yes. I resend this later.
> > + pm_runtime_put_sync_suspend(bank->dev);
> > + else {
> > + pm_runtime_mark_last_busy(bank->dev);
> > + pm_runtime_put_sync_autosuspend(bank->dev);
> > + }
> > }
> > }
> >
> > --
> > 1.7.2.5
> >
> > --
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> > the body of a message to majord...@vger.kernel.org
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>
--
Tim Niemeyer
Corscience GmbH & Co. KG
Henkestr. 91
D-91052 Erlangen
Germany
e-mail: tim.nieme...@corscience.de
Internet: www.corscience.de
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