1 files changed, 47 insertions, 11 deletions

diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c
index b922db90939a..a67119199c45 100644
--- a/drivers/dma/stm32-dmamux.c
+++ b/drivers/dma/stm32-dmamux.c
@@ -28,6 +28,7 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
+#include <linux/pm_runtime.h>
 #include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -79,8 +80,7 @@ static void stm32_dmamux_free(struct device *dev, void *route_data)
         stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
         clear_bit(mux->chan_id, dmamux->dma_inuse);
 
-        if (!IS_ERR(dmamux->clk))
-                clk_disable(dmamux->clk);
+        pm_runtime_put_sync(dev);
 
         spin_unlock_irqrestore(&dmamux->lock, flags);
 
@@ -146,13 +146,10 @@ static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
 
         /* Set dma request */
         spin_lock_irqsave(&dmamux->lock, flags);
-        if (!IS_ERR(dmamux->clk)) {
-                ret = clk_enable(dmamux->clk);
-                if (ret < 0) {
-                        spin_unlock_irqrestore(&dmamux->lock, flags);
-                        dev_err(&pdev->dev, "clk_prep_enable issue: %d\n", ret);
-                        goto error;
-                }
+        ret = pm_runtime_get_sync(&pdev->dev);
+        if (ret < 0) {
+                spin_unlock_irqrestore(&dmamux->lock, flags);
+                goto error;
         }
         spin_unlock_irqrestore(&dmamux->lock, flags);
 
@@ -254,6 +251,7 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
                 dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
                          stm32_dmamux->dmamux_requests);
         }
+        pm_runtime_get_noresume(&pdev->dev);
 
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         iomem = devm_ioremap_resource(&pdev->dev, res);
@@ -282,6 +280,8 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
         stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
 
         platform_set_drvdata(pdev, stm32_dmamux);
+        pm_runtime_set_active(&pdev->dev);
+        pm_runtime_enable(&pdev->dev);
 
         if (!IS_ERR(stm32_dmamux->clk)) {
                 ret = clk_prepare_enable(stm32_dmamux->clk);
@@ -291,17 +291,52 @@ static int stm32_dmamux_probe(struct platform_device *pdev)
                 }
         }
 
+        pm_runtime_get_noresume(&pdev->dev);
+
         /* Reset the dmamux */
         for (i = 0; i < stm32_dmamux->dma_requests; i++)
                 stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
 
-        if (!IS_ERR(stm32_dmamux->clk))
-                clk_disable(stm32_dmamux->clk);
+        pm_runtime_put(&pdev->dev);
 
         return of_dma_router_register(node, stm32_dmamux_route_allocate,
                                      &stm32_dmamux->dmarouter);
 }
 
+#ifdef CONFIG_PM
+static int stm32_dmamux_runtime_suspend(struct device *dev)
+{
+        struct platform_device *pdev =
+                container_of(dev, struct platform_device, dev);
+        struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+
+        clk_disable_unprepare(stm32_dmamux->clk);
+
+        return 0;
+}
+
+static int stm32_dmamux_runtime_resume(struct device *dev)
+{
+        struct platform_device *pdev =
+                container_of(dev, struct platform_device, dev);
+        struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+        int ret;
+
+        ret = clk_prepare_enable(stm32_dmamux->clk);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to prepare_enable clock\n");
+                return ret;
+        }
+
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops stm32_dmamux_pm_ops = {
+        SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
+                           stm32_dmamux_runtime_resume, NULL)
+};
+
 static const struct of_device_id stm32_dmamux_match[] = {
         { .compatible = "st,stm32h7-dmamux" },
         {},
@@ -312,6 +347,7 @@ static struct platform_driver stm32_dmamux_driver = {
         .driver = {
                 .name = "stm32-dmamux",
                 .of_match_table = stm32_dmamux_match,
+                .pm = &stm32_dmamux_pm_ops,
         },
 };