[PATCH 0/4] STM32 DMAMUX driver fixes and improvements

@@ -41,6 +41,9 @@ struct stm32_dmamux_data {
 	u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
 	spinlock_t lock; /* Protects register access */
 	unsigned long *dma_inuse; /* Used DMA channel */
+	u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
+						 * in suspend
+						 */
 	u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
 			 *  [0] holds number of DMA Masters.
 			 *  To be kept at very end end of this structure

@@ -318,7 +321,54 @@ static int stm32_dmamux_runtime_resume(struct device *dev)
 }
 #endif
 
+#ifdef CONFIG_PM_SLEEP
+static int stm32_dmamux_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+	int i, ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < stm32_dmamux->dma_requests; i++)
+		stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
+							 STM32_DMAMUX_CCR(i));
+
+	pm_runtime_put_sync(dev);
+
+	pm_runtime_force_suspend(dev);
+
+	return 0;
+}
+
+static int stm32_dmamux_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+	int i, ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < stm32_dmamux->dma_requests; i++)
+		stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
+				   stm32_dmamux->ccr[i]);
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+#endif
+
 static const struct dev_pm_ops stm32_dmamux_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
 	SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
 			   stm32_dmamux_runtime_resume, NULL)
 };

@@ -259,6 +259,12 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = clk_prepare_enable(stm32_dmamux->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
+		return ret;
+	}
+
 	stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL);
 	if (!IS_ERR(stm32_dmamux->rst)) {
 		reset_control_assert(stm32_dmamux->rst);

@@ -274,14 +280,6 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
-	if (!IS_ERR(stm32_dmamux->clk)) {
-		ret = clk_prepare_enable(stm32_dmamux->clk);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
-			return ret;
-		}
-	}
-
 	pm_runtime_get_noresume(&pdev->dev);
 
 	/* Reset the dmamux */

@@ -290,8 +288,12 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 
 	pm_runtime_put(&pdev->dev);
 
-	return of_dma_router_register(node, stm32_dmamux_route_allocate,
+	ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
 				     &stm32_dmamux->dmarouter);
+	if (ret)
+		clk_disable_unprepare(stm32_dmamux->clk);
+
+	return ret;
 }
 
 #ifdef CONFIG_PM

@@ -254,8 +254,8 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 	stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(stm32_dmamux->clk)) {
 		ret = PTR_ERR(stm32_dmamux->clk);
-		if (ret == -EPROBE_DEFER)
-			dev_info(&pdev->dev, "Missing controller clock\n");
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Missing clock controller\n");
 		return ret;
 	}
 

@@ -266,7 +266,11 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 	}
 
 	rst = devm_reset_control_get(&pdev->dev, NULL);
-	if (!IS_ERR(rst)) {
+	if (IS_ERR(rst)) {
+		ret = PTR_ERR(rst);
+		if (ret == -EPROBE_DEFER)
+			goto err_clk;
+	} else {
 		reset_control_assert(rst);
 		udelay(2);
 		reset_control_deassert(rst);

@@ -291,7 +295,12 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 	ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
 				     &stm32_dmamux->dmarouter);
 	if (ret)
-		clk_disable_unprepare(stm32_dmamux->clk);
+		goto err_clk;
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(stm32_dmamux->clk);
 
 	return ret;
 }

@@ -35,7 +35,6 @@ struct stm32_dmamux {
 struct stm32_dmamux_data {
 	struct dma_router dmarouter;
 	struct clk *clk;
-	struct reset_control *rst;
 	void __iomem *iomem;
 	u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
 	u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */

@@ -182,6 +181,7 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 	struct stm32_dmamux_data *stm32_dmamux;
 	struct resource *res;
 	void __iomem *iomem;
+	struct reset_control *rst;
 	int i, count, ret;
 	u32 dma_req;
 

@@ -265,11 +265,11 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL);
-	if (!IS_ERR(stm32_dmamux->rst)) {
-		reset_control_assert(stm32_dmamux->rst);
+	rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (!IS_ERR(rst)) {
+		reset_control_assert(rst);
 		udelay(2);
-		reset_control_deassert(stm32_dmamux->rst);
+		reset_control_deassert(rst);
 	}
 
 	stm32_dmamux->iomem = iomem;