spi: omap2-mcspi: add support for pm_runtime autosuspend

Adds support for configuring the omap2-mcspi driver use autosuspend for
runtime power management. This can reduce the latency in starting an
spi transfer by not suspending the device immediately following
completion of a transfer. If another transfer then takes place before
the autosuspend timeout (2 secs), the call to resume the device can
return immediately saving some save/ restore cycles.

Acked-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 1907ed2e2958944597e80db2b41bd4668c86a0ac..0b0da2f7ce239d72a855e8fccdd64e0ae43b7340 100644 (file)
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -44,6 +44,7 @@
 #include <plat/mcspi.h>
 
 #define OMAP2_MCSPI_MAX_FREQ           48000000
+#define SPI_AUTOSUSPEND_TIMEOUT                2000
 
 #define OMAP2_MCSPI_REVISION           0x00
 #define OMAP2_MCSPI_SYSSTATUS          0x14
@@ -265,7 +266,8 @@ static void omap2_mcspi_restore_ctx(struct omap2_mcspi *mcspi)
 }
 static void omap2_mcspi_disable_clocks(struct omap2_mcspi *mcspi)
 {
-       pm_runtime_put_sync(mcspi->dev);
+       pm_runtime_mark_last_busy(mcspi->dev);
+       pm_runtime_put_autosuspend(mcspi->dev);
 }
 
 static int omap2_mcspi_enable_clocks(struct omap2_mcspi *mcspi)
@@ -1212,6 +1214,8 @@ static int __devinit omap2_mcspi_probe(struct platform_device *pdev)
        if (status < 0)
                goto dma_chnl_free;
 
+       pm_runtime_use_autosuspend(&pdev->dev);
+       pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
        pm_runtime_enable(&pdev->dev);
 
        if (status || omap2_mcspi_master_setup(mcspi) < 0)