On 11/9/2011 4:09 PM, Linus WALLEIJ wrote:
> From: Chris Blair <chris.bl...@stericsson.com>
>
> Adds support for configuring the spi bus to 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, the call to resume the device can return
> immediately rather than needing to risk sleeping in order to resume
> the device.
>
> Signed-off-by: Chris Blair <chris.bl...@stericsson.com>
> Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
> ---
> drivers/spi/spi-pl022.c | 20 ++++++++++++++++++--
> include/linux/amba/pl022.h | 4 ++++
> 2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
> index 2e3522d..d3d6521 100644
> --- a/drivers/spi/spi-pl022.c
> +++ b/drivers/spi/spi-pl022.c
> @@ -1515,7 +1515,13 @@ static void pump_messages(struct work_struct *work)
> /* nothing more to do - disable spi/ssp and power off */
> writew((readw(SSP_CR1(pl022->virtbase)) &
> (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));
> - pm_runtime_put(&pl022->adev->dev);
> +
> + if (pl022->master_info->autosuspend_delay > 0) {
> + pm_runtime_mark_last_busy(&pl022->adev->dev);
> + pm_runtime_put_autosuspend(&pl022->adev->dev);
> + } else {
> + pm_runtime_put(&pl022->adev->dev);
> + }
> }
> pl022->busy = false;
> spin_unlock_irqrestore(&pl022->queue_lock, flags);
> @@ -2245,7 +2251,17 @@ pl022_probe(struct amba_device *adev, const struct
> amba_id *id)
> dev_dbg(dev, "probe succeeded\n");
>
> /* let runtime pm put suspend */
> - pm_runtime_put(dev);
> + if (platform_info->autosuspend_delay > 0) {
> + dev_info(&adev->dev,
> + "will use autosuspend for runtime pm, delay %dms\n",
> + platform_info->autosuspend_delay);
> + pm_runtime_set_autosuspend_delay(dev,
> + platform_info->autosuspend_delay);
> + pm_runtime_use_autosuspend(dev);
> + pm_runtime_put_autosuspend(dev);
> + } else {
> + pm_runtime_put(dev);
> + }
> return 0;
>
> err_spi_register:
> diff --git a/include/linux/amba/pl022.h b/include/linux/amba/pl022.h
> index 4ce98f5..572f637 100644
> --- a/include/linux/amba/pl022.h
> +++ b/include/linux/amba/pl022.h
> @@ -238,6 +238,9 @@ struct dma_chan;
> * @enable_dma: if true enables DMA driven transfers.
> * @dma_rx_param: parameter to locate an RX DMA channel.
> * @dma_tx_param: parameter to locate a TX DMA channel.
> + * @autosuspend_delay: delay in ms following transfer completion before the
> + * runtime power management system suspends the device. A setting of 0
> + * indicates no delay and the device will be suspended immediately.
> */
> struct pl022_ssp_controller {
> u16 bus_id;
> @@ -246,6 +249,7 @@ struct pl022_ssp_controller {
> bool (*dma_filter)(struct dma_chan *chan, void *filter_param);
> void *dma_rx_param;
> void *dma_tx_param;
> + int autosuspend_delay;
> };
>
> /**
Reviewed-by: Viresh Kumar <viresh.ku...@st.com>
--
viresh
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