On Mon, 2021-07-05 at 16:09 +0800, Tzung-Bi Shih wrote:

On Wed, Jun 30, 2021 at 3:56 PM kyrie.wu [off-list ref] wrote:

quoted

Mt8195 has two hardwares, "mediatek,mt8195-jpgenc0" for hw0 and
"mediatek,mt8195-jpgenc1" for HW1. These two nodes will register
hardware interrupt, initialize clock, power domain, remap register base
addr and other operations. But the device node is not registered.
"mediatek,mt8195-jpgenc" will register the device node to represent jpeg
encode device. Then the component framework is used to manage the above
two hardwares.

Please don't top-posting.  Inline your replies so that people can
easily follow the discussion.

I still don't quite understand why it needs to introduce 2 compatible
strings.  If hw0 and hw1 are different from interrupts, clocks, power
domain, and etc, couldn't you use the same compatible string (e.g.
"mt8195-jpgenc") and provide them different DT attributes?

Dear Tzung-Bi,

As you replied, I can use the same compatible string (e.g
"mt8195-jpgenc") and provide resources with different DT attributes.
But there are the following problems:
The following description takes the resource of clock as an example:
1. If different DT attributes are used to represent different clock
information,the structure array (e.g.struct clkinfo) can be used in the
driver to save the corresponding information, which will increase the
complexity of the software;
2. When using hw0, you only need to turn on clock0, but not clock1,
which can reduce power consumption. When the driver uses one of the
clocks, it needs to extract each structure from structure array
(e.g.struct clkinfo) and compare the attributes to confirming which one
to use.
The software architecture is as follows:
if (...) {
[...]
} else if (...) {
[...]
} 
......
At present, there are only two HWS, and the software architecture is not
complex. With the increase of the number of hardware, the software
architecture will become more and more complex.
To sum up, using different compatibles to represent different HW
can reduce power consumption, decrease code complexity
and enhance code readability.

quoted

On Fri, 2021-06-25 at 17:18 +0800, Tzung-Bi Shih wrote:

quoted

On Wed, Jun 23, 2021 at 2:06 PM kyrie.wu [off-list ref] wrote:

quoted

 Documentation/devicetree/bindings/media/mediatek-jpeg-encoder.txt | 3 +++
 1 file changed, 3 insertions(+)

Note: the patch won't apply after [1].

[1]: https://lore.kernel.org/patchwork/patch/1445298/

quoted

 Required properties:
 - compatible : "mediatek,mt2701-jpgenc"
+- compatible : "mediatek,mt8195-jpgenc"
+- compatible : "mediatek,mt8195-jpgenc0"
+- compatible : "mediatek,mt8195-jpgenc1"

Why it needs 3 compatible strings?

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