From mboxrd@z Thu Jan 1 00:00:00 1970 From: slongerbeam@gmail.com (Steve Longerbeam) Date: Sat, 3 Jun 2017 12:38:01 -0700 Subject: [PATCH v7 16/34] [media] add Omnivision OV5640 sensor driver In-Reply-To: <20170601082659.GJ1019@valkosipuli.retiisi.org.uk> References: <1495672189-29164-1-git-send-email-steve_longerbeam@mentor.com> <1495672189-29164-17-git-send-email-steve_longerbeam@mentor.com> <20170531195821.GA16962@amd> <20170601082659.GJ1019@valkosipuli.retiisi.org.uk> Message-ID: <755909bf-d1de-e0f3-1569-0d4b16e26817@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 06/01/2017 01:26 AM, Sakari Ailus wrote: > Hi Pavel, > > On Wed, May 31, 2017 at 09:58:21PM +0200, Pavel Machek wrote: >> Hi! >> >>> +/* min/typical/max system clock (xclk) frequencies */ >>> +#define OV5640_XCLK_MIN 6000000 >>> +#define OV5640_XCLK_MAX 24000000 >>> + >>> +/* >>> + * FIXME: there is no subdev API to set the MIPI CSI-2 >>> + * virtual channel yet, so this is hardcoded for now. >>> + */ >>> +#define OV5640_MIPI_VC 1 >> >> Can the FIXME be fixed? > > Yes, but it's quite a bit of work. It makes sense to use a static virtual > channel for now. A patchset which is however incomplete can be found here: > > > > For what it's worth, all other devices use virtual channel zero for image > data and so should this one. Actually no. The CSI2IPU gasket in i.MX6 quad sends virtual channel 0 streams to IPU1-CSI0. But input to IPU1-CSI0 is also muxed with parallel bus cameras. So if vc0 were chosen instead, platforms that support parallel cameras to IPU1-CSI0 (SabreLite, SabreSD) would not be able to use them concurrently with a MIPI CSI-2 source to IPU1-CSI1. So I prefer to use static channel 1 to support those platforms. I could convert this to a module parameter however, until a virtual channel selection subdev API becomes available, at which point that would have to be stripped. > >> >>> +/* >>> + * image size under 1280 * 960 are SUBSAMPLING >> >> -> Image >> >>> + * image size upper 1280 * 960 are SCALING >> >> above? >> done. >>> +/* >>> + * FIXME: all of these register tables are likely filled with >>> + * entries that set the register to their power-on default values, >>> + * and which are otherwise not touched by this driver. Those entries >>> + * should be identified and removed to speed register load time >>> + * over i2c. >>> + */ >> >> load->loading? Can the FIXME be fixed? That's a lot of work, and risky work at that. If someone could take this on (strip out power-on default values from the tables), I'd be grateful, but I don't have the time. For now at least, these registers sets work fine. >> >>> + /* Auto/manual exposure */ >>> + ctrls->auto_exp = v4l2_ctrl_new_std_menu(hdl, ops, >>> + V4L2_CID_EXPOSURE_AUTO, >>> + V4L2_EXPOSURE_MANUAL, 0, >>> + V4L2_EXPOSURE_AUTO); >>> + ctrls->exposure = v4l2_ctrl_new_std(hdl, ops, >>> + V4L2_CID_EXPOSURE_ABSOLUTE, >>> + 0, 65535, 1, 0); >> >> Is exposure_absolute supposed to be in microseconds...? > > Yes. According to the docs V4L2_CID_EXPOSURE_ABSOLUTE is in 100 usec units. OTOH V4L2_CID_EXPOSURE has no defined unit, so it's a better fit IMO. > Way more drivers appear to be using EXPOSURE than EXPOSURE_ABSOLUTE, too. Done, switched to V4L2_CID_EXPOSURE. It's true, this control is not taking 100 usec units, so unit-less is better. Steve