Thread (13 messages) 13 messages, 2 authors, 2016-12-12

Re: [PATCH v5 1/2] Add OV5647 device tree documentation

From: Ramiro Oliveira <hidden>
Date: 2016-12-12 12:15:17
Also in: linux-media, lkml

Hi Sakari

On 12/12/2016 11:49 AM, Sakari Ailus wrote:
Hi Ramiro,

On Mon, Dec 12, 2016 at 11:39:31AM +0000, Ramiro Oliveira wrote:
quoted
Hi Sakari,

Thank you for the feedback.

On 12/7/2016 10:33 PM, Sakari Ailus wrote:
quoted
Hi Ramiro,

Thank you for the patch.

On Mon, Dec 05, 2016 at 05:36:33PM +0000, Ramiro Oliveira wrote:
quoted
Add device tree documentation.

Signed-off-by: Ramiro Oliveira <roliveir-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
---
 .../devicetree/bindings/media/i2c/ov5647.txt          | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov5647.txt
diff --git a/Documentation/devicetree/bindings/media/i2c/ov5647.txt b/Documentation/devicetree/bindings/media/i2c/ov5647.txt
new file mode 100644
index 0000000..4c91b3b
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ov5647.txt
@@ -0,0 +1,19 @@
+Omnivision OV5647 raw image sensor
+---------------------------------
+
+OV5647 is a raw image sensor with MIPI CSI-2 and CCP2 image data interfaces
+and CCI (I2C compatible) control bus.
+
+Required properties:
+
+- compatible	: "ovti,ov5647";
+- reg		: I2C slave address of the sensor;
+
+The common video interfaces bindings (see video-interfaces.txt) should be
+used to specify link to the image data receiver. The OV5647 device
+node should contain one 'port' child node with an 'endpoint' subnode.
+
+Following properties are valid for the endpoint node:
+
+- data-lanes : (optional) specifies MIPI CSI-2 data lanes as covered in
+  video-interfaces.txt.  The sensor supports only two data lanes.
Doesn't this sensor require a external clock, a reset GPIO and / or a
regulator or a few? Do you need data-lanes, unless you can change the order
or the number?
In the setup I'm using, I'm not aware of any reset GPIO or regulator. I do use a
external clock but it's fixed and not controlled by SW. Should I add a property
for this?
The sensor datasheet defines a power-up and power-down sequence for the
device. If you don't implement these sequences in the driver on a DT based
system, nothing suggests that they're implemented correctly. Could it be
that the boot loader simply enables the regulators or another device
requires them to be enabled?

I presume at least the reset GPIO should be controlled explicitly in order
to ensure correct function. Although hardware can be surprising: I have one
production system that has no reset GPIO for the sensor albeit the sensor
datasheet says that's part of the power up sequence.
Sorry for the misunderstanding. I wanted to say that, there is no SW controlled
reset. In the board we're using to connect the sensor to our D-PHY we have a
GPIO controller that when it receives power, it removes the sensor from reset,
so I have no control over that.

Regarding the clock, should I create a new property?

And also, regarding the data-lanes, AFAIK it isn't possible to change the order
of the data and clock lanes so should I remove that property?
quoted
quoted
An example DT snippet wouldn't hurt.
Sure, I can add a example snippet.
quoted
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