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Subject[RESEND PATCH v1 3/3] dmaengine: stm32-mdma: Add PM Runtime support
Date
Use pm_runtime engine for clock management purpose

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
Version history:
v1:
* Initial
---
---
drivers/dma/stm32-mdma.c | 52 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 46 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index 390e4ca..ac0301b 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -37,6 +37,7 @@
#include <linux/of_device.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/slab.h>

@@ -1456,15 +1457,13 @@ static int stm32_mdma_alloc_chan_resources(struct dma_chan *c)
return -ENOMEM;
}

- ret = clk_prepare_enable(dmadev->clk);
- if (ret < 0) {
- dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
+ ret = pm_runtime_get_sync(dmadev->ddev.dev);
+ if (ret < 0)
return ret;
- }

ret = stm32_mdma_disable_chan(chan);
if (ret < 0)
- clk_disable_unprepare(dmadev->clk);
+ pm_runtime_put(dmadev->ddev.dev);

return ret;
}
@@ -1484,7 +1483,7 @@ static void stm32_mdma_free_chan_resources(struct dma_chan *c)
spin_unlock_irqrestore(&chan->vchan.lock, flags);
}

- clk_disable_unprepare(dmadev->clk);
+ pm_runtime_put(dmadev->ddev.dev);
vchan_free_chan_resources(to_virt_chan(c));
dmam_pool_destroy(chan->desc_pool);
chan->desc_pool = NULL;
@@ -1597,6 +1596,12 @@ static int stm32_mdma_probe(struct platform_device *pdev)
return ret;
}

+ ret = clk_prepare_enable(dmadev->clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
+ return ret;
+ }
+
dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
if (!IS_ERR(dmadev->rst)) {
reset_control_assert(dmadev->rst);
@@ -1668,6 +1673,10 @@ static int stm32_mdma_probe(struct platform_device *pdev)
}

platform_set_drvdata(pdev, dmadev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_get_noresume(&pdev->dev);
+ pm_runtime_put(&pdev->dev);

dev_info(&pdev->dev, "STM32 MDMA driver registered\n");

@@ -1677,11 +1686,42 @@ static int stm32_mdma_probe(struct platform_device *pdev)
return ret;
}

+#ifdef CONFIG_PM
+static int stm32_mdma_runtime_suspend(struct device *dev)
+{
+ struct stm32_mdma_device *dmadev = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(dmadev->clk);
+
+ return 0;
+}
+
+static int stm32_mdma_runtime_resume(struct device *dev)
+{
+ struct stm32_mdma_device *dmadev = dev_get_drvdata(dev);
+ int ret;
+
+ ret = clk_prepare_enable(dmadev->clk);
+ if (ret) {
+ dev_err(dev, "failed to prepare_enable clock\n");
+ return ret;
+ }
+
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops stm32_mdma_pm_ops = {
+ SET_RUNTIME_PM_OPS(stm32_mdma_runtime_suspend,
+ stm32_mdma_runtime_resume, NULL)
+};
+
static struct platform_driver stm32_mdma_driver = {
.probe = stm32_mdma_probe,
.driver = {
.name = "stm32-mdma",
.of_match_table = stm32_mdma_of_match,
+ .pm = &stm32_mdma_pm_ops,
},
};

--
2.7.4
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