dmaengine: stm32-dmamux: fix clock handling in probe sequence

This change ensures the DMAMUX device is reset only once it is clocked
and that clock is released in a safe state when probe operation fails.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20200128094158.20361-3-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c
index 08d2395..a862d33 100644 (file)
--- a/drivers/dma/stm32-dmamux.c
+++ b/drivers/dma/stm32-dmamux.c
@@ -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