On Tue, Sep 8, 2015 at 3:45 PM, Hans de Goede <[email protected]> wrote: > Hi, > > On 07-09-15 22:56, Maxime Ripard wrote: >> >> On Mon, Sep 07, 2015 at 09:05:29AM +0200, Hans de Goede wrote: >>>>> >>>>> +®_ldo3 { >>>>> + /* >>>>> + * We need to always power the camera sensor, otherwhise all >>>>> access >>>>> + * to i2c1 is blocked. >>>>> + */ >>>>> + regulator-always-on; >>>>> + regulator-min-microvolt = <2800000>; >>>>> + regulator-max-microvolt = <2800000>; >>>>> + regulator-name = "vdd-csi"; >>>>> +}; >>>> >>>> >>>> What is connected on i2c1 ? Just the camera sensor? or it has some >>>> other devices there? >>> >>> >>> The bma250 accelerometer sits there, and the kernel already has a driver >>> for it. That driver needs to have devicetree binding support added, and >>> then we should be able to use the accelerometer. >> >> >> Ok, so if this regulator is disable, you can't access the other >> devices as well, right? > > > Right, the controller reports the bus as being stuck. > >> Do you know why? Is it the regulator providing >> the pull-up voltage? > > > I've tried enabling the pull ups on the SoC i2c pins, so I do not think > that it is that, it seems that somehow when not powered the camera sensor is > actively keeping the lines low. Either it has multiple power planes, or > it is using normally-on fet-s between ground and its i2c lines.
FYI the reference designs use one regulator to power the pull-ups, VCC-PX (X for X pin group), and VDDIO (IO power)on the camera sensors. AVDD, DVDD (actual power) for the sensors are another (or more) regulators. ChenYu -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
