dmaengine: stm32-dma: add suspend/resume power management support

Add suspend/resume power management relying on PM Runtime engine.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20200129153628.29329-2-amelie.delaunay@st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 5989b08935211537026f289a0b1eb5bc320b4284..136deabd1aa3f47c8ad00de3eb9f98883ce6fdb9 100644 (file)
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -1427,7 +1427,39 @@ static int stm32_dma_runtime_resume(struct device *dev)
 }
 #endif
 
+#ifdef CONFIG_PM_SLEEP
+static int stm32_dma_suspend(struct device *dev)
+{
+       struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
+       int id, ret, scr;
+
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0)
+               return ret;
+
+       for (id = 0; id < STM32_DMA_MAX_CHANNELS; id++) {
+               scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
+               if (scr & STM32_DMA_SCR_EN) {
+                       dev_warn(dev, "Suspend is prevented by Chan %i\n", id);
+                       return -EBUSY;
+               }
+       }
+
+       pm_runtime_put_sync(dev);
+
+       pm_runtime_force_suspend(dev);
+
+       return 0;
+}
+
+static int stm32_dma_resume(struct device *dev)
+{
+       return pm_runtime_force_resume(dev);
+}
+#endif
+
 static const struct dev_pm_ops stm32_dma_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(stm32_dma_suspend, stm32_dma_resume)
        SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend,
                           stm32_dma_runtime_resume, NULL)
 };