[PATCH 3/6] dmaengine: mxs: add the power management functions

[Han Xu <han.xu@xxxxxxx>]

add the power management functions and leverage the runtime pm for
system suspend/resume

Signed-off-by: Han Xu <han.xu@xxxxxxx>
---
 drivers/dma/mxs-dma.c | 97 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 90 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index b458f06f9067..251492c5ea58 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -25,6 +25,7 @@
 #include <linux/of_dma.h>
 #include <linux/list.h>
 #include <linux/dma/mxs-dma.h>
+#include <linux/pm_runtime.h>
 
 #include <asm/irq.h>
 
@@ -39,6 +40,8 @@
 #define dma_is_apbh(mxs_dma)	((mxs_dma)->type == MXS_DMA_APBH)
 #define apbh_is_old(mxs_dma)	((mxs_dma)->dev_id == IMX23_DMA)
 
+#define MXS_DMA_RPM_TIMEOUT 50 /* ms */
+
 #define HW_APBHX_CTRL0				0x000
 #define BM_APBH_CTRL0_APB_BURST8_EN		(1 << 29)
 #define BM_APBH_CTRL0_APB_BURST_EN		(1 << 28)
@@ -416,6 +419,7 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	struct device *dev = &mxs_dma->pdev->dev;
 	int ret;
 
 	mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev,
@@ -431,9 +435,11 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
 	if (ret)
 		goto err_irq;
 
-	ret = clk_prepare_enable(mxs_dma->clk);
-	if (ret)
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable clock\n");
 		goto err_clk;
+	}
 
 	mxs_dma_reset_chan(chan);
 
@@ -458,6 +464,7 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
 {
 	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+	struct device *dev = &mxs_dma->pdev->dev;
 
 	mxs_dma_disable_chan(chan);
 
@@ -466,7 +473,9 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
 	dma_free_coherent(mxs_dma->dma_device.dev, CCW_BLOCK_SIZE,
 			mxs_chan->ccw, mxs_chan->ccw_phys);
 
-	clk_disable_unprepare(mxs_dma->clk);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
 }
 
 /*
@@ -689,14 +698,32 @@ static enum dma_status mxs_dma_tx_status(struct dma_chan *chan,
 	return mxs_chan->status;
 }
 
-static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
+static int mxs_dma_init_rpm(struct mxs_dma_engine *mxs_dma)
 {
+	struct device *dev = &mxs_dma->pdev->dev;
+
+	pm_runtime_enable(dev);
+	pm_runtime_set_autosuspend_delay(dev, MXS_DMA_RPM_TIMEOUT);
+	pm_runtime_use_autosuspend(dev);
+
+	return 0;
+}
+
+static int mxs_dma_init(struct mxs_dma_engine *mxs_dma)
+{
+	struct device *dev = &mxs_dma->pdev->dev;
 	int ret;
 
-	ret = clk_prepare_enable(mxs_dma->clk);
+	ret = mxs_dma_init_rpm(mxs_dma);
 	if (ret)
 		return ret;
 
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
 	ret = stmp_reset_block(mxs_dma->base);
 	if (ret)
 		goto err_out;
@@ -714,7 +741,8 @@ static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
 		mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_SET);
 
 err_out:
-	clk_disable_unprepare(mxs_dma->clk);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 	return ret;
 }
 
@@ -821,11 +849,13 @@ static int mxs_dma_probe(struct platform_device *pdev)
 			&mxs_dma->dma_device.channels);
 	}
 
+	platform_set_drvdata(pdev, mxs_dma);
+	mxs_dma->pdev = pdev;
+
 	ret = mxs_dma_init(mxs_dma);
 	if (ret)
 		return ret;
 
-	mxs_dma->pdev = pdev;
 	mxs_dma->dma_device.dev = &pdev->dev;
 
 	/* mxs_dma gets 65535 bytes maximum sg size */
@@ -879,9 +909,62 @@ static int mxs_dma_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int mxs_dma_pm_suspend(struct device *dev)
+{
+	int ret;
+
+	ret = pm_runtime_force_suspend(dev);
+
+	return ret;
+}
+
+static int mxs_dma_pm_resume(struct device *dev)
+{
+	struct mxs_dma_engine *mxs_dma = dev_get_drvdata(dev);
+	int ret;
+
+	ret = mxs_dma_init(mxs_dma);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+#endif
+
+int mxs_dma_runtime_suspend(struct device *dev)
+{
+	struct mxs_dma_engine *mxs_dma = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(mxs_dma->clk);
+
+	return 0;
+}
+
+int mxs_dma_runtime_resume(struct device *dev)
+{
+	struct mxs_dma_engine *mxs_dma = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(mxs_dma->clk);
+	if (ret) {
+		dev_err(&mxs_dma->pdev->dev, "failed to enable the clock\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops mxs_dma_pm_ops = {
+	SET_RUNTIME_PM_OPS(mxs_dma_runtime_suspend,
+			   mxs_dma_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(mxs_dma_pm_suspend, mxs_dma_pm_resume)
+};
+
 static struct platform_driver mxs_dma_driver = {
 	.driver		= {
 		.name	= "mxs-dma",
+		.pm = &mxs_dma_pm_ops,
 		.of_match_table = mxs_dma_dt_ids,
 	},
 	.id_table	= mxs_dma_ids,
-- 
2.17.1