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Subject[RESEND PATCH v1 1/3] dmaengine: stm32-dma: 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-dma.c | 58 +++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 48f7c0f..ba239b5 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -23,6 +23,7 @@
#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/sched.h>
#include <linux/slab.h>
@@ -1115,15 +1116,14 @@ static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
int ret;

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

return ret;
}
@@ -1143,7 +1143,7 @@ static void stm32_dma_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));
}
@@ -1243,6 +1243,12 @@ static int stm32_dma_probe(struct platform_device *pdev)
return PTR_ERR(dmadev->clk);
}

+ ret = clk_prepare_enable(dmadev->clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
+ return ret;
+ }
+
dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
"st,mem2mem");

@@ -1292,7 +1298,7 @@ static int stm32_dma_probe(struct platform_device *pdev)

ret = dma_async_device_register(dd);
if (ret)
- return ret;
+ goto clk_free;

for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
chan = &dmadev->chan[i];
@@ -1324,20 +1330,58 @@ static int stm32_dma_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 DMA driver registered\n");

return 0;

err_unregister:
dma_async_device_unregister(dd);
+clk_free:
+ clk_disable_unprepare(dmadev->clk);

return ret;
}

+#ifdef CONFIG_PM
+static int stm32_dma_runtime_suspend(struct device *dev)
+{
+ struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(dmadev->clk);
+
+ return 0;
+}
+
+static int stm32_dma_runtime_resume(struct device *dev)
+{
+ struct stm32_dma_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_dma_pm_ops = {
+ SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend,
+ stm32_dma_runtime_resume, NULL)
+};
+
static struct platform_driver stm32_dma_driver = {
.driver = {
.name = "stm32-dma",
.of_match_table = stm32_dma_of_match,
+ .pm = &stm32_dma_pm_ops,
},
};

--
2.7.4
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