linux-kernel - [PATCH 1/6] dmaengine: stm32-mdma: add suspend/resume power management support

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Message-ID: <20200127085334.13163-2-amelie.delaunay@st.com>
Date:   Mon, 27 Jan 2020 09:53:29 +0100
From:   Amelie Delaunay <amelie.delaunay@...com>
To:     Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>
CC:     <dmaengine@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Amelie Delaunay <amelie.delaunay@...com>,
        Pierre-Yves MORDRET <pierre-yves.mordret@...com>
Subject: [PATCH 1/6] dmaengine: stm32-mdma: add suspend/resume power management support

From: Pierre-Yves MORDRET <pierre-yves.mordret@...com>

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

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@...com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
---
 drivers/dma/stm32-mdma.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index 5838311cf990..2898411941d5 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -1697,7 +1697,40 @@ static int stm32_mdma_runtime_resume(struct device *dev)
 }
 #endif
 
+#ifdef CONFIG_PM_SLEEP
+static int stm32_mdma_pm_suspend(struct device *dev)
+{
+	struct stm32_mdma_device *dmadev = dev_get_drvdata(dev);
+	u32 ccr, id;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0)
+		return ret;
+
+	for (id = 0; id < dmadev->nr_channels; id++) {
+		ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(id));
+		if (ccr & STM32_MDMA_CCR_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_mdma_pm_resume(struct device *dev)
+{
+	return pm_runtime_force_resume(dev);
+}
+#endif
+
 static const struct dev_pm_ops stm32_mdma_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_mdma_pm_suspend, stm32_mdma_pm_resume)
 	SET_RUNTIME_PM_OPS(stm32_mdma_runtime_suspend,
 			   stm32_mdma_runtime_resume, NULL)
 };
-- 
2.17.1