> -----Original Message----- > From: Juan Jesús García de Soria Lucena [mailto:skandalfo@xxxxxxxxx] > Sent: Thursday, February 05, 2009 1:26 AM > To: Curran, Dominic > Cc: linux-media@xxxxxxxxxxxxxxx > Subject: Re: [REVIEW][PATCH] LV8093: Add driver for LV8093 lens actuator. > > Hi. > > 2009/2/4 Dominic Curran <dcurran@xxxxxx>: > > The device has only one read register which contains a single BUSY bit. > > For large relative lens movements the device can be busy for sometime and we > need > > to know when the lens has stopped moving. > > > > My question is what is the most appropriate mechanism to read the BUSY bit ? > > > > Currently the driver uses the VIDIOC_G_CTRL ioctl + V4L2_CID_FOCUS_RELATIVE > ctrl > > ID to return the BUSY bit. Is this acceptable ? > > [...] > > > A 3rd solution is to read the BUSY bit everytime after a write and not > return > > until device is ready. However this adds extra time to the operation > > (particularly for small lens moves) and I would like the user to be in > change of > > when the reads of BUSY bit occur. > > And what about waiting for not BUSY at the *beginning* of the next > lens adjustment if the previous one hasn't finished yet? This could be > combined with either a polling interface or a sync style interface > (wait for not BUSY function) for the case in which the user wants to > actually be sure that the lens got up to its target state. Yes, poll would be a good solution, but I'm can not workout how I can add a poll() method to a v4l slave driver ? Are there an examples of such v4l slave drivers you can point me too ? All the v4l drivers I can find that have .poll fops register using video_register_device(). My slave driver uses v4l2_int_device_register(). Any pointers appreciated. Thanks dom -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
