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Subject[PATCH v11 5/6] dmaengine: pl330: Add PM sleep support
Date
Add system suspend/resume capabilities to the pl330 driver so the amba
bus clock could be also unprepared to conserve energy.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
---
drivers/dma/pl330.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index c3bd3584f261..fd71777fc565 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2627,6 +2627,42 @@ static int pl330_dma_device_slave_caps(struct dma_chan *dchan,
return 0;
}

+/*
+ * Runtime PM callbacks are provided by amba/bus.c driver.
+ *
+ * It is assumed here that IRQ safe runtime PM is chosen in probe and amba
+ * bus driver will only disable/enable the clock in runtime PM callbacks.
+ */
+static int __maybe_unused pl330_suspend(struct device *dev)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+
+ if (!pm_runtime_status_suspended(dev)) {
+ /* amba did not disable the clock */
+ amba_pclk_disable(pcdev);
+ }
+ amba_pclk_unprepare(pcdev);
+
+ return 0;
+}
+
+static int __maybe_unused pl330_resume(struct device *dev)
+{
+ struct amba_device *pcdev = to_amba_device(dev);
+ int ret;
+
+ ret = amba_pclk_prepare(pcdev);
+ if (ret)
+ return ret;
+
+ if (!pm_runtime_status_suspended(dev))
+ ret = amba_pclk_enable(pcdev);
+
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(pl330_pm, pl330_suspend, pl330_resume);
+
static int
pl330_probe(struct amba_device *adev, const struct amba_id *id)
{
@@ -2853,6 +2889,7 @@ static struct amba_driver pl330_driver = {
.drv = {
.owner = THIS_MODULE,
.name = "dma-pl330",
+ .pm = &pl330_pm,
},
.id_table = pl330_ids,
.probe = pl330_probe,
--
1.9.1


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