Re: [PATCHv2] dt: bindings: Add support for CSI1 bus
From: Sakari Ailus <hidden>
Date: 2017-01-19 21:49:06
Also in:
linux-media
Hi Pavel, On Wed, Jan 11, 2017 at 11:53:35PM +0100, Pavel Machek wrote:
quoted hunk ↗ jump to hunk
From: Sakari Ailus <redacted> In the vast majority of cases the bus type is known to the driver(s) since a receiver or transmitter can only support a single one. There are cases however where different options are possible. The existing V4L2 OF support tries to figure out the bus type and parse the bus parameters based on that. This does not scale too well as there are multiple serial busses that share common properties. Some hardware also supports multiple types of busses on the same interfaces. Document the CSI1/CCP2 property strobe. It signifies the clock or strobe mode. Signed-off-by: Sakari Ailus <redacted> Signed-off-by: Ivaylo Dimitrov <redacted> Signed-off-by: Pavel Machek <redacted>diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt index 9cd2a36..08c4498 100644 --- a/Documentation/devicetree/bindings/media/video-interfaces.txt +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt@@ -76,6 +76,11 @@ Optional endpoint properties mode horizontal and vertical synchronization signals are provided to the slave device (data source) by the master device (data sink). In the master mode the data source device is also the source of the synchronization signals. +- bus-type: data bus type. Possible values are: + 0 - MIPI CSI2 + 1 - parallel / Bt656 + 2 - MIPI CSI1 + 3 - CCP2
Actually, thinking about this again --- we only need to explictly specify busses if we're dealing with either CCP2 or CSI-1. The vast majority of the actual busses are and continue to be CSI-2 or either parallel or Bt.656. As they can be implicitly detected, we would have an option to just drop values 0 and 1 from above, i.e. only leave CSI-1 and CCP2. For now, specifying CSI-2 or parallel / Bt.656 adds no value as the old DT binaries without bus-type will need to be supported anyway.
quoted hunk ↗ jump to hunk
- bus-width: number of data lines actively used, valid for the parallel busses. - data-shift: on the parallel data busses, if bus-width is used to specify the number of data lines, data-shift can be used to specify which data lines are@@ -112,7 +117,8 @@ Optional endpoint properties should be the combined length of data-lanes and clock-lanes properties. If the lane-polarities property is omitted, the value must be interpreted as 0 (normal). This property is valid for serial busses only. - +- strobe: Whether the clock signal is used as clock or strobe. Used + with CCP2, for instance.
How about the "ti,strobe-clock-inv" I proposed? No-one seems to know what this really truly means... or just drop it if it's not really needed. -- Cheers, Sakari Ailus e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org XMPP: sailus-PCDdDYkjdNMDXYZnReoRVg@public.gmane.org -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html