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.niemeyer@xxxxxxxxxxxxx>
---
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) {
+ 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)
+ 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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