Hi Hans, On Fri, Nov 25, 2022 at 12:15:57PM +0100, Hans de Goede wrote: > On 11/25/22 11:58, Laurent Pinchart wrote: > > On Fri, Nov 25, 2022 at 10:17:17AM +0000, Dan Scally wrote: > >> Morning Hans - thanks for the set > >> > >> On 24/11/2022 20:00, Hans de Goede wrote: > >>> Hi All, > >>> > >>> Here is a small set of patches to make the int3472/discrete code > >>> work with the sensor drivers bundled with the (unfortunately out of tree) > >>> IPU6 driver. > >>> > >>> There are parts of the out of tree IPU6 code, like the sensor drivers, > >>> which can be moved to the mainline and I do plan to work on this at some > >>> point and then some of this might need to change. But for now the goal is > >>> to make the out of tree driver work with standard mainline distro kernels > >>> through e.g. dkms. Otherwise users need to run a patched kernel just for > >>> a couple of small differences. > >>> > >>> This is basically a rewrite of this patch: > >>> https://github.com/intel/ipu6-drivers/blob/master/patch/int3472-support-independent-clock-and-LED-gpios-5.17%2B.patch > >>> > >>> Wich users who want to use the IPU6 driver so far have had to manually > >>> apply to their kernels which is quite inconvenient. > >>> > >>> This rewrite makes 2 significant changes: > >>> > >>> 1. Don't break things on IPU3 platforms > >>> > >>> 2. Instead of extending the int3472_sensor_configs[] quirks table for each > >>> model which needs "clken" and "pled" GPIOs, do this based on matching > >>> the ACPI HID of the ACPI device describing the sensor. > >>> > >>> The need for these GPIOs is a property of the specific sensor driver which > >>> binds using this same HID, so by using this we avoid having to extend the > >>> int3472_sensor_configs[] quirks table all the time. > >>> > >>> This allows roling back the behavior to at least use a clk-framework > >>> clk instead of clken GPIO on a per sensor(-driver) basis as we mainline > >>> the sensor drivers, assuming that the drivers are switched over to the > >>> clk framework as part of their mainlining. > >>> > >>> A bigger question is what to do with the privacy-led GPIO on IPU3 > >>> we so far have turned the LED on/off at the same as te clock, > >>> but at least on some IPU6 models this won't work, because they only > >>> have a privacy-led GPIO and no clk_en GPIO (there is no sensor > >>> clk-control at all on some models). > >> > >> Ah how annoying, we hadn't come across any situations for IPU3 with a > >> privacy LED but no clock GPIO > >> > >>> I think we should maybe move all models, including IPU3 based > >>> models over to using a normal GPIO for controlling the privacy-led > >>> to make things consistent. > >> > >> I think they probably should be represented as LED devices then, and > >> have the media subsytem call some framework to find associated LEDs and > >> cycle them at power on time in the sensor drivers. I know there's the > >> v4l2_flash structure at the moment, but not sure if a privacy one exists. > > > > The whole point of a privacy LED is to be controlled automatically (and > > ideally without software intervention, but that's a different story). > > Can the LED framework be used without having the LED exposed to > > userspace ? > > AFAIK using the LED framework will automatically expose the LED > to userspace; and using triggers as I mentioned in my other email > will also allow the user to unset the trigger or even use a different > trigger. > > I understand where you are coming from, but I was actually seeing > this (exposed to userspace) as a feature. Users may want to repurpose > the LED, maybe make it blink when the camera is on for extra obviousness > the camera is on. Maybe always have it off because it is too annoying, > etc... ? One use case for turning it off is avoiding reflection in glasses. I however think this is outweighted by the privacy concerns. If the privacy LED can be controlled from userspace, at least by default, then it could as well be dropped completely. > My vision here is that ideally the LED should be hardwired to go on > together with some enable pin or power-supply of the sensor. To make it secure it should be controlled by the hardware, yes. > But if it is actually just a GPIO, then there is something to be said > for giving the user full-control. OTOH this would make writing spy-ware > where the LED never goes on a lot easier... > > Typing this out I'm afraid that I have to agree with you and that > the spyware argument likely wins over how giving the user more control > would be nice :( I also wish we could get both privacy and flexibility :-( I'm not necessarily opposed to making it controllable by userspace, but that shouldn't be the default. It could be controlled by a kernel command line argument for instance. I doubt that would be worth it though. > Which would bring us back to just making it a GPIO, which would then > need to be turned on+off by the sensor driver I guess. > > There seems to be a bunch of GPIO/clk/regulator boilerplate duplicated > in all the sensor drivers. I think a little helper-library for this might > be in order. E.g. Something like this (in the .h file) I fully agree that camera sensor helpers would be good to have. > struct camera_sensor_pwr_helper { > // bunch of stuff here, this should be fixed size so that the > // sensor drivers can embed it into their driver-data struct > }; > > int camera_sensor_pwr_helper_init(struct camera_sensor_pwr_helper *helper, > const char *supply_names, int supply_count, > const char* clk_name. > /* other stuff which I'm probably forgetting right now */); There are all kind of constraints on the power on/off sequences, I don't think we would be able to model this in a generic way without making it so complicated that it would outweight the benefits. What I think could help is moving all camera sensor drivers to runtime PM, and having helpers to properly enable runtime PM in probe() in a way that works on both ACPI and DT systems, with or without CONFIG_PM enabled. It's way more complicated than it sounds. > // turn_on_privacy_led should be false when called from probe(), must be true when > // called on stream_on(). > int camera_sensor_pwr_helper_on(struct camera_sensor_pwr_helper *helper, bool turn_on_privacy_led); > int camera_sensor_pwr_helper_off(struct camera_sensor_pwr_helper *helper); > > // maybe, or make everything devm managed? : > int camera_sensor_pwr_helper_exit(struct camera_sensor_pwr_helper *helper); > > Just is just a really really quick n dirty design. For one I could use > suggestions for a better name for the thing :) > > I think something like this will be helpfull to reduce a whole bunch > of boilerplate code related to powering on/off the sensor in all > the drivers; and it would give us a central place to drive an > (optional) privacy-led GPIO. > > >>> And likewise (eventually) completely drop the "clken" GPIO this > >>> patch series introduces (with some sensors) and instead always model > >>> this through the clk-framework. > >>> > >>> Hans de Goede (3): > >>> platform/x86: int3472/discrete: Refactor GPIO to sensor mapping > >>> platform/x86: int3472/discrete: Get the polarity from the _DSM entry > >>> platform/x86: int3472/discrete: Add support for sensor-drivers which > >>> expect clken + pled GPIOs > >>> > >>> drivers/platform/x86/intel/int3472/common.h | 2 +- > >>> drivers/platform/x86/intel/int3472/discrete.c | 92 ++++++++++++++++--- > >>> 2 files changed, 78 insertions(+), 16 deletions(-) -- Regards, Laurent Pinchart
