Hi Val
On Mon, 8 Feb 2010, Valentin Longchamp wrote:
> > /*
> > * Power Management:
> > * This function does nothing for now but must be present for pm to work
> > */
> > static int mt9t031_runtime_suspend(struct device *dev)
> > {
> > return 0;
> > }
>
> First, can you confirm me that this function is needed even if it does nothing
> ? I have read in the code that if the function is not present,
> __pm_runtime_suspend is going to return -ENOSYS and will set runtime_status to
> RPM_ACTIVE, which is not what we want. That's why I left it.
Yes, I think, you're right - if neither bus, nor type, nor class suspend
is debined, -ENOSYS is returned (see __pm_runtime_suspend()).
> > /*
> > * Power Management:
> > * COLUMN_ADDRESS_MODE and ROW_ADDRESS_MODE are not rewritten if unchanged
> > * they are however changed at reset if the platform hook is present
> > * thus we rewrite them with the values stored by the driver
> > */
> > static int mt9t031_runtime_resume(struct device *dev)
> > {
> > struct video_device *vdev = to_video_device(dev);
> > struct soc_camera_device *icd = container_of(vdev->parent,
> > struct soc_camera_device, dev);
> > struct device *i2c_dev = container_of(icd, struct device,
> > platform_data);
> > struct i2c_client *client = to_i2c_client(i2c_dev);
> > struct mt9t031 *mt9t031 = to_mt9t031(client);
>
> Here I have a problem ... I am pretty sure that the third assignation has a
> problem, because platform_data is a pointer and not a normal member of struct
> device, and I thus cannot use container_of with it. What would then be the way
> to go from the soc_camera_device to the i2c_client (I'm a little bit confused
> with all the different structs and layers involved with i2c, soc-camera,
> v4l2_device and v4l2_subdevice) ?
struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
struct i2c_client *client = sd->priv;
> Just as a remark, this is the exact reverse
> path of this that is present in your patch to add runtime pm support to
> soc-camera:
>
> /* This is only temporary here - until v4l2-subdev begins to link to
> video_device */
> #include <linux/i2c.h>
> static inline struct video_device *soc_camera_i2c_to_vdev(struct i2c_client
> *client)
> {
> struct soc_camera_device *icd = client->dev.platform_data;
> return icd->vdev;
> }
>
> >
> > int ret;
> > u16 xbin, ybin;
> >
> > xbin = min(mt9t031->xskip, (u16)3);
> > ybin = min(mt9t031->yskip, (u16)3);
> >
> > ret = reg_write(client, MT9T031_COLUMN_ADDRESS_MODE,
> > ((xbin-1)<<4) | (mt9t031->xskip-1));
> > if (ret < 0)
> > return ret;
> >
> > ret = reg_write(client, MT9T031_ROW_ADDRESS_MODE,
> > ((ybin-1)<<4) | (mt9t031->yskip-1));
> > if (ret < 0)
> > return ret;
> >
> > return 0;
> > }
> >
> > static struct dev_pm_ops mt9t031_dev_pm_ops = {
> > .runtime_suspend = mt9t031_runtime_suspend,
> > .runtime_resume = mt9t031_runtime_resume,
> > };
> >
> > static struct device_type mt9t031_dev_type = {
> > .name = "MT9T031",
> > .pm = &mt9t031_dev_pm_ops,
> > };
>
> Thank you in advance for your help.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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