[PATCH V2] dmaengine: tegra-apb: Really fix runtime-pm usage

[Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

Commit edd3bdbe9db1 ("dmaengine: tegra-apb: Correct runtime-pm usage")
added pm_runtime_get/put() calls to the tegra-apb DMA system suspend
callbacks. Runtime PM is disabled during system suspend and so these
APIs cannot be used. Fix the suspend handling for the tegra-apb DMA by
moving the save and restore of the DMA register context into the
runtime PM suspend and resume callbacks, and then use the
pm_runtime_force_suspend/resume() APIs to invoke the runtime PM
callbacks during system suspend.

Fixes: edd3bdbe9db1 ("dmaengine: tegra-apb: Correct runtime-pm usage")

Signed-off-by: Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---

Changes since V1:
- Drop the custom suspend/resume callbacks and use
  pm_runtime_force_suspend/resume directly in SET_SYSTEM_SLEEP_PM_OPS.

 drivers/dma/tegra20-apb-dma.c | 50 +++++++++----------------------------------
 1 file changed, 10 insertions(+), 40 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 3722b9d8d9fe..b9d75a54c896 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1494,35 +1494,7 @@ static int tegra_dma_remove(struct platform_device *pdev)
 static int tegra_dma_runtime_suspend(struct device *dev)
 {
 	struct tegra_dma *tdma = dev_get_drvdata(dev);
-
-	clk_disable_unprepare(tdma->dma_clk);
-	return 0;
-}
-
-static int tegra_dma_runtime_resume(struct device *dev)
-{
-	struct tegra_dma *tdma = dev_get_drvdata(dev);
-	int ret;
-
-	ret = clk_prepare_enable(tdma->dma_clk);
-	if (ret < 0) {
-		dev_err(dev, "clk_enable failed: %d\n", ret);
-		return ret;
-	}
-	return 0;
-}
-
-#ifdef CONFIG_PM_SLEEP
-static int tegra_dma_pm_suspend(struct device *dev)
-{
-	struct tegra_dma *tdma = dev_get_drvdata(dev);
 	int i;
-	int ret;
-
-	/* Enable clock before accessing register */
-	ret = pm_runtime_get_sync(dev);
-	if (ret < 0)
-		return ret;
 
 	tdma->reg_gen = tdma_read(tdma, TEGRA_APBDMA_GENERAL);
 	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
@@ -1543,21 +1515,21 @@ static int tegra_dma_pm_suspend(struct device *dev)
 						  TEGRA_APBDMA_CHAN_WCOUNT);
 	}
 
-	/* Disable clock */
-	pm_runtime_put(dev);
+	clk_disable_unprepare(tdma->dma_clk);
+
 	return 0;
 }
 
-static int tegra_dma_pm_resume(struct device *dev)
+static int tegra_dma_runtime_resume(struct device *dev)
 {
 	struct tegra_dma *tdma = dev_get_drvdata(dev);
-	int i;
-	int ret;
+	int i, ret;
 
-	/* Enable clock before accessing register */
-	ret = pm_runtime_get_sync(dev);
-	if (ret < 0)
+	ret = clk_prepare_enable(tdma->dma_clk);
+	if (ret < 0) {
+		dev_err(dev, "clk_enable failed: %d\n", ret);
 		return ret;
+	}
 
 	tdma_write(tdma, TEGRA_APBDMA_GENERAL, tdma->reg_gen);
 	tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
@@ -1582,16 +1554,14 @@ static int tegra_dma_pm_resume(struct device *dev)
 			(ch_reg->csr & ~TEGRA_APBDMA_CSR_ENB));
 	}
 
-	/* Disable clock */
-	pm_runtime_put(dev);
 	return 0;
 }
-#endif
 
 static const struct dev_pm_ops tegra_dma_dev_pm_ops = {
 	SET_RUNTIME_PM_OPS(tegra_dma_runtime_suspend, tegra_dma_runtime_resume,
 			   NULL)
-	SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
 };
 
 static const struct of_device_id tegra_dma_of_match[] = {
-- 
2.7.4