On Tue, 2017-01-31 at 00:01 +0000, Russell King - ARM Linux wrote: [...] > The iMX6 manuals call for a very specific seven sequence of initialisation > for CSI2, which begins with: > > 1. reset the D-PHY. > 2. place MIPI sensor in LP-11 state > 3. perform D-PHY initialisation > 4. configure CSI2 lanes and de-assert resets and shutdown signals > > Since you reset the CSI2 at power up and then release it, how do you > guarantee that the published sequence is followed? > > With Philipp's driver, this is easy, because there is a prepare_stream > callback which gives the sensor an opportunity to get everything > correctly configured according to the negotiated parameters, and place > the sensor in LP-11 state. > > Some sensors do not power up in LP-11 state, but need to be programmed > fully before being asked to momentarily stream. Only at that point is > the sensor guaranteed to be in the required LP-11 state. Do you expect that 1. and 2. could depend on the negotiated parameters in any way on some hardware? I had removed the prepare_stream callback from my driver in v2 because for my use case at least the above sequence could be realized by 1. in imx-mipi-csi2 s_power(1) 2. in MIPI sensor s_power(1) 3./4. in imx-mipi-csi2 s_stream(1) 4. in MIPI sensor s_stream(1) as long as the sensor is correctly put back into LP-11 in s_stream(0). regards Philipp _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
