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Subject[PATCH v2] media: stm32-dcmi: add power saving support
Date
Implements runtime & system sleep power management ops.

Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
---
version 2:
- Fix missing include file detected by kbuild on i386 & sparc64 arch:
- https://www.mail-archive.com/linux-media@vger.kernel.org/msg132766.html
- https://www.mail-archive.com/linux-media@vger.kernel.org/msg132771.html

drivers/media/platform/stm32/stm32-dcmi.c | 81 +++++++++++++++++++++++++------
1 file changed, 65 insertions(+), 16 deletions(-)

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 2e1933d..2ecf00e 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -22,7 +22,9 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_graph.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/videodev2.h>

@@ -578,9 +580,9 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
u32 val = 0;
int ret;

- ret = clk_enable(dcmi->mclk);
+ ret = pm_runtime_get_sync(dcmi->dev);
if (ret) {
- dev_err(dcmi->dev, "%s: Failed to start streaming, cannot enable clock\n",
+ dev_err(dcmi->dev, "%s: Failed to start streaming, cannot get sync\n",
__func__);
goto err_release_buffers;
}
@@ -590,7 +592,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
if (ret && ret != -ENOIOCTLCMD) {
dev_err(dcmi->dev, "%s: Failed to start streaming, subdev streamon error",
__func__);
- goto err_disable_clock;
+ goto err_pm_put;
}

spin_lock_irq(&dcmi->irqlock);
@@ -675,8 +677,8 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
err_subdev_streamoff:
v4l2_subdev_call(dcmi->entity.subdev, video, s_stream, 0);

-err_disable_clock:
- clk_disable(dcmi->mclk);
+err_pm_put:
+ pm_runtime_put(dcmi->dev);

err_release_buffers:
spin_lock_irq(&dcmi->irqlock);
@@ -749,7 +751,7 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
/* Stop all pending DMA operations */
dmaengine_terminate_all(dcmi->dma_chan);

- clk_disable(dcmi->mclk);
+ pm_runtime_put(dcmi->dev);

if (dcmi->errors_count)
dev_warn(dcmi->dev, "Some errors found while streaming: errors=%d (overrun=%d), buffers=%d\n",
@@ -1751,12 +1753,6 @@ static int dcmi_probe(struct platform_device *pdev)
return -EPROBE_DEFER;
}

- ret = clk_prepare(mclk);
- if (ret) {
- dev_err(&pdev->dev, "Unable to prepare mclk %p\n", mclk);
- goto err_dma_release;
- }
-
spin_lock_init(&dcmi->irqlock);
mutex_init(&dcmi->lock);
init_completion(&dcmi->complete);
@@ -1772,7 +1768,7 @@ static int dcmi_probe(struct platform_device *pdev)
/* Initialize the top-level structure */
ret = v4l2_device_register(&pdev->dev, &dcmi->v4l2_dev);
if (ret)
- goto err_clk_unprepare;
+ goto err_dma_release;

dcmi->vdev = video_device_alloc();
if (!dcmi->vdev) {
@@ -1832,14 +1828,15 @@ static int dcmi_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Probe done\n");

platform_set_drvdata(pdev, dcmi);
+
+ pm_runtime_enable(&pdev->dev);
+
return 0;

err_device_release:
video_device_release(dcmi->vdev);
err_device_unregister:
v4l2_device_unregister(&dcmi->v4l2_dev);
-err_clk_unprepare:
- clk_unprepare(dcmi->mclk);
err_dma_release:
dma_release_channel(dcmi->dma_chan);

@@ -1850,20 +1847,72 @@ static int dcmi_remove(struct platform_device *pdev)
{
struct stm32_dcmi *dcmi = platform_get_drvdata(pdev);

+ pm_runtime_disable(&pdev->dev);
+
v4l2_async_notifier_unregister(&dcmi->notifier);
v4l2_device_unregister(&dcmi->v4l2_dev);
- clk_unprepare(dcmi->mclk);
+
dma_release_channel(dcmi->dma_chan);

return 0;
}

+static __maybe_unused int dcmi_runtime_suspend(struct device *dev)
+{
+ struct stm32_dcmi *dcmi = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(dcmi->mclk);
+
+ return 0;
+}
+
+static __maybe_unused int dcmi_runtime_resume(struct device *dev)
+{
+ struct stm32_dcmi *dcmi = dev_get_drvdata(dev);
+ int ret;
+
+ ret = clk_prepare_enable(dcmi->mclk);
+ if (ret)
+ dev_err(dev, "%s: Failed to prepare_enable clock\n", __func__);
+
+ return ret;
+}
+
+static __maybe_unused int dcmi_suspend(struct device *dev)
+{
+ /* disable clock */
+ pm_runtime_force_suspend(dev);
+
+ /* change pinctrl state */
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static __maybe_unused int dcmi_resume(struct device *dev)
+{
+ /* restore pinctl default state */
+ pinctrl_pm_select_default_state(dev);
+
+ /* clock enable */
+ pm_runtime_force_resume(dev);
+
+ return 0;
+}
+
+static const struct dev_pm_ops dcmi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(dcmi_suspend, dcmi_resume)
+ SET_RUNTIME_PM_OPS(dcmi_runtime_suspend,
+ dcmi_runtime_resume, NULL)
+};
+
static struct platform_driver stm32_dcmi_driver = {
.probe = dcmi_probe,
.remove = dcmi_remove,
.driver = {
.name = DRV_NAME,
.of_match_table = of_match_ptr(stm32_dcmi_of_match),
+ .pm = &dcmi_pm_ops,
},
};

--
1.9.1
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