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.
> + 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.
> + 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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