dmaengine: stm32-dmamux: 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/20200128094158.20361-2-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 3c89bd3..08d2395 100644 (file)
--- a/drivers/dma/stm32-dmamux.c
+++ b/drivers/dma/stm32-dmamux.c
@@ -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)
 };