Re: [PATCH v6 03/10] Documentation: devicetree: Update Samsung FIMC DT binding
Hi Sylwester,
On Tuesday 11 March 2014 14:38:37 Sylwester Nawrocki wrote:
> Hi Laurent,
>
> Thanks for your review.
You're welcome.
> On 11/03/14 13:30, Laurent Pinchart wrote:
> [...]
>
> >> ---
> >>
> >> .../devicetree/bindings/media/samsung-fimc.txt | 34 +-
> >> 1 file changed, 26 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt
> >> b/Documentation/devicetree/bindings/media/samsung-fimc.txt index
> >> 96312f6..dbd4020 100644
> >> --- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
> >> +++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
> >> @@ -32,6 +32,21 @@ way around.
> >>
> >> The 'camera' node must include at least one 'fimc' child node.
> >>
> >> +Optional properties:
> >> +
> >> +- #clock-cells: from the common clock bindings
> >> (../clock/clock-bindings.txt),
> >> + must be 1. A clock provider is associated with the 'camera' node and
> >> it should
> >> + be referenced by external sensors that use clocks provided by the SoC
> >> on
> >> + CAM_*_CLKOUT pins. The clock specifier cell stores an index of a
> >> clock.
> >> + The indices are 0, 1 for CAM_A_CLKOUT, CAM_B_CLKOUT clocks
> >> respectively.
> >> +
> >> +- clock-output-names: from the common clock bindings, should contain
> >> names of
> >> + clocks registered by the camera subsystem corresponding to
> >> CAM_A_CLKOUT,
> >> + CAM_B_CLKOUT output clocks respectively.
> >
> > Wouldn't it be better to document the "cam_mclk_a" and "cam_mclk_b" names
> > explicitly ? Or do you expect different names to be used in different DT
> > files ? And as they correspond to the CAM_A_CLKOUT and CAM_B_CLKOUT pins,
> > shouldn't they be named "cam_a_clkout" and "cam_b_clkout" ?
>
> Basically I could use fixed names for these clocks, I just wanted to keep
> a possibility to override them in dts to avoid any possible clock name
> collisions, rather than keep a list of different names per SoC in the
> driver. Right now fixed names could also be used for all SoCs I'm aware of,
> nevertheless I would prefer to keep the clock-output-names property.
> "cam_a_clkout", "cam_b_clkout" may be indeed better names, I'll change
> that.
OK, variable names are fine with me.
> >> +Note: #clock-cells and clock-output-names are mandatory properties if
> >> external
> >> +image sensor devices reference 'camera' device node as a clock provider.
> >> +
> >
> > What's the reason not to make them always mandatory ? Backward
> > compatibility only ? If so wouldn't it make sense to document the
> > properties as mandatory from now on, and treating them as optional in the
> > driver for backward compatibility ?
>
> Yes, it's for backwards compatibility only. It may be a good idea to just
> document them as required, since this is how the device is expected to be
> described in DT from now. I'll just make these a required properties,
> the driver already handles them as optional.
OK.
> >> 'fimc' device nodes
> >> ---
> >>
> >> @@ -97,8 +112,8 @@ Image sensor nodes
> >>
> >> The sensor device nodes should be added to their control bus controller
> >>
> >> (e.g. I2C0) nodes and linked to a port node in the csis or the
> >> parallel-ports node, using the common video interfaces bindings, defined
> >> in video-interfaces.txt.
> >> -The implementation of this bindings requires clock-frequency property to
> >> be
> >> -present in the sensor device nodes.
> >> +An optional clock-frequency property needs to be present in the sensor
> >> device
> >> +nodes. Default value when this property is not present is 24 MHz.
> >
> > This bothers me. Having the FIMC driver read the clock-frequence property
> > from the sensor DT nodes feels like a layering violation. Shouldn't the
> > sensor drivers call clk_set_rate() explicitly instead ?
>
> It is supposed to do so, after this whole patch series. So the camera
> controller driver will not need such properties. What do you think about
> removing this sentence altogether ?
Sure. As the FIMC won't access the clock-frequency property of the sensor
anymore after this patch series, let's just drop the mention of clock-
frequency.
> >> Example:
> >> @@ -114,7 +129,7 @@ Example:
> >>vddio-supply = <...>;
> >>
> >>clock-frequency = <2400>;
> >>
> >> - clocks = <...>;
> >> + clocks = <&camera 1>;
> >>
> >>clock-names = "mclk";
> >>
> >>port {
> >>
> >> @@ -135,7 +150,7 @@ Example:
> >>vddio-supply = <...>;
> >>
> >>clock-frequency = <2400>;
> >>
> >> - clocks = <...>;
> >> + clocks = <&camera 0>;
> >>
> >>clock-names = "mclk";
> >>
> >>port {
> >>
> >> @@ -149,12 +164,15 @@ Example:
> >>
Re: [PATCH v6 03/10] Documentation: devicetree: Update Samsung FIMC DT binding
Hi Laurent,
Thanks for your review.
On 11/03/14 13:30, Laurent Pinchart wrote:
[...]
>> ---
>> .../devicetree/bindings/media/samsung-fimc.txt | 34 -
>> 1 file changed, 26 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt
>> b/Documentation/devicetree/bindings/media/samsung-fimc.txt index
>> 96312f6..dbd4020 100644
>> --- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
>> +++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
>> @@ -32,6 +32,21 @@ way around.
>>
>> The 'camera' node must include at least one 'fimc' child node.
>>
>> +Optional properties:
>> +
>> +- #clock-cells: from the common clock bindings
>> (../clock/clock-bindings.txt),
>> + must be 1. A clock provider is associated with the 'camera' node and it
>> should
>> + be referenced by external sensors that use clocks provided by the SoC on
>> + CAM_*_CLKOUT pins. The clock specifier cell stores an index of a clock.
>> + The indices are 0, 1 for CAM_A_CLKOUT, CAM_B_CLKOUT clocks respectively.
>> +
>> +- clock-output-names: from the common clock bindings, should contain names
>> of
>> + clocks registered by the camera subsystem corresponding to CAM_A_CLKOUT,
>> + CAM_B_CLKOUT output clocks respectively.
>
> Wouldn't it be better to document the "cam_mclk_a" and "cam_mclk_b" names
> explicitly ? Or do you expect different names to be used in different DT
> files
> ? And as they correspond to the CAM_A_CLKOUT and CAM_B_CLKOUT pins, shouldn't
> they be named "cam_a_clkout" and "cam_b_clkout" ?
Basically I could use fixed names for these clocks, I just wanted to keep
a possibility to override them in dts to avoid any possible clock name
collisions, rather than keep a list of different names per SoC in the driver.
Right now fixed names could also be used for all SoCs I'm aware of,
nevertheless I would prefer to keep the clock-output-names property.
"cam_a_clkout", "cam_b_clkout" may be indeed better names, I'll change
that.
>> +Note: #clock-cells and clock-output-names are mandatory properties if
>> external
>> +image sensor devices reference 'camera' device node as a clock provider.
>> +
>
> What's the reason not to make them always mandatory ? Backward compatibility
> only ? If so wouldn't it make sense to document the properties as mandatory
> from now on, and treating them as optional in the driver for backward
> compatibility ?
Yes, it's for backwards compatibility only. It may be a good idea to just
document them as required, since this is how the device is expected to be
described in DT from now. I'll just make these a required properties,
the driver already handles them as optional.
>> 'fimc' device nodes
>> ---
>>
>> @@ -97,8 +112,8 @@ Image sensor nodes
>> The sensor device nodes should be added to their control bus controller
>> (e.g. I2C0) nodes and linked to a port node in the csis or the
>> parallel-ports node, using the common video interfaces bindings, defined in
>> video-interfaces.txt.
>> -The implementation of this bindings requires clock-frequency property to be
>> -present in the sensor device nodes.
>> +An optional clock-frequency property needs to be present in the sensor
>> device
>> +nodes. Default value when this property is not present is 24 MHz.
>
> This bothers me. Having the FIMC driver read the clock-frequence property
> from
> the sensor DT nodes feels like a layering violation. Shouldn't the sensor
> drivers call clk_set_rate() explicitly instead ?
It is supposed to do so, after this whole patch series. So the camera
controller driver will not need such properties. What do you think about
removing this sentence altogether ?
>> Example:
>>
>> @@ -114,7 +129,7 @@ Example:
>> vddio-supply = <...>;
>>
>> clock-frequency = <2400>;
>> -clocks = <...>;
>> +clocks = <&camera 1>;
>> clock-names = "mclk";
>>
>> port {
>> @@ -135,7 +150,7 @@ Example:
>> vddio-supply = <...>;
>>
>> clock-frequency = <2400>;
>> -clocks = <...>;
>> +clocks = <&camera 0>;
>> clock-names = "mclk";
>>
>> port {
>> @@ -149,12 +164,15 @@ Example:
>>
>> camera {
>> compatible = "samsung,fimc", "simple-bus";
>> -#address-cells = <1>;
>> -#size-cells = <1>;
>> -status = "okay";
>> -
>> +clocks = <&clock 132>, <&clock 133>;
>> +clock-names = "sclk_cam0", "sclk_cam1";
>
> The documentation mentions that clock-names must contain "sclk_cam0",
> "sclk_cam1", "pxl_async0", "pxl_async1". Are the last two optional ? If so I
> think you should clarify the description of the clock-names property. This
> can
> be done in a separate patch.
"pxl_async0", "pxl_async1" are mandatory, I'l
Re: [PATCH v6 03/10] Documentation: devicetree: Update Samsung FIMC DT binding
Hi Sylwester,
Thank you for the patch.
On Thursday 06 March 2014 17:20:12 Sylwester Nawrocki wrote:
> This patch documents following updates of the Exynos4 SoC camera subsystem
> devicetree binding:
>
> - addition of #clock-cells property to 'camera' node - the #clock-cells
>property is needed when the sensor sub-devices use clock provided by
>the camera host interface,
> - addition of an optional clock-output-names property,
> - change of the clock-frequency at image sensor node from mandatory to
>an optional property - the sensor devices can now control their clock
>themselves and there should be no need to require this property by the
>camera host device binding, a default frequency value can often be used.
>
> Signed-off-by: Sylwester Nawrocki
> Acked-by: Kyungmin Park
> ---
> Changes since v5:
> - none.
>
> Changes since v4:
> - dropped a requirement of specific order of values in clocks/
>clock-names properties (Mark) and reference to clock-names in
>clock-output-names property description (Mark).
> ---
> .../devicetree/bindings/media/samsung-fimc.txt | 34 -
> 1 file changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt
> b/Documentation/devicetree/bindings/media/samsung-fimc.txt index
> 96312f6..dbd4020 100644
> --- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
> +++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
> @@ -32,6 +32,21 @@ way around.
>
> The 'camera' node must include at least one 'fimc' child node.
>
> +Optional properties:
> +
> +- #clock-cells: from the common clock bindings
> (../clock/clock-bindings.txt),
> + must be 1. A clock provider is associated with the 'camera' node and it
> should
> + be referenced by external sensors that use clocks provided by the SoC on
> + CAM_*_CLKOUT pins. The clock specifier cell stores an index of a clock.
> + The indices are 0, 1 for CAM_A_CLKOUT, CAM_B_CLKOUT clocks respectively.
> +
> +- clock-output-names: from the common clock bindings, should contain names
> of
> + clocks registered by the camera subsystem corresponding to CAM_A_CLKOUT,
> + CAM_B_CLKOUT output clocks respectively.
Wouldn't it be better to document the "cam_mclk_a" and "cam_mclk_b" names
explicitly ? Or do you expect different names to be used in different DT files
? And as they correspond to the CAM_A_CLKOUT and CAM_B_CLKOUT pins, shouldn't
they be named "cam_a_clkout" and "cam_b_clkout" ?
> +
> +Note: #clock-cells and clock-output-names are mandatory properties if
> external
> +image sensor devices reference 'camera' device node as a clock provider.
> +
What's the reason not to make them always mandatory ? Backward compatibility
only ? If so wouldn't it make sense to document the properties as mandatory
from now on, and treating them as optional in the driver for backward
compatibility ?
> 'fimc' device nodes
> ---
>
> @@ -97,8 +112,8 @@ Image sensor nodes
> The sensor device nodes should be added to their control bus controller
> (e.g. I2C0) nodes and linked to a port node in the csis or the
> parallel-ports node, using the common video interfaces bindings, defined in
> video-interfaces.txt.
> -The implementation of this bindings requires clock-frequency property to be
> -present in the sensor device nodes.
> +An optional clock-frequency property needs to be present in the sensor
> device
> +nodes. Default value when this property is not present is 24 MHz.
This bothers me. Having the FIMC driver read the clock-frequence property from
the sensor DT nodes feels like a layering violation. Shouldn't the sensor
drivers call clk_set_rate() explicitly instead ?
> Example:
>
> @@ -114,7 +129,7 @@ Example:
> vddio-supply = <...>;
>
> clock-frequency = <2400>;
> - clocks = <...>;
> + clocks = <&camera 1>;
> clock-names = "mclk";
>
> port {
> @@ -135,7 +150,7 @@ Example:
> vddio-supply = <...>;
>
> clock-frequency = <2400>;
> - clocks = <...>;
> + clocks = <&camera 0>;
> clock-names = "mclk";
>
> port {
> @@ -149,12 +164,15 @@ Example:
>
> camera {
> compatible = "samsung,fimc", "simple-bus";
> - #address-cells = <1>;
> - #size-cells = <1>;
> - status = "okay";
> -
> + clocks = <&clock 132>, <&clock 133>;
> + clock-names = "sclk_cam0", "sclk_cam1";
The documentation mentions that clock-names must contain "sclk_cam0",
"sclk_cam1", "pxl_async0", "pxl_async1". Are the last two optional ? If so I
think you should clarify the description of the clock-names property. This can
be done in a separate patch.
> + #clock-cells = <1>;
> +
[PATCH v6 03/10] Documentation: devicetree: Update Samsung FIMC DT binding
This patch documents following updates of the Exynos4 SoC camera subsystem
devicetree binding:
- addition of #clock-cells property to 'camera' node - the #clock-cells
property is needed when the sensor sub-devices use clock provided by
the camera host interface,
- addition of an optional clock-output-names property,
- change of the clock-frequency at image sensor node from mandatory to
an optional property - the sensor devices can now control their clock
themselves and there should be no need to require this property by the
camera host device binding, a default frequency value can often be used.
Signed-off-by: Sylwester Nawrocki
Acked-by: Kyungmin Park
---
Changes since v5:
- none.
Changes since v4:
- dropped a requirement of specific order of values in clocks/
clock-names properties (Mark) and reference to clock-names in
clock-output-names property description (Mark).
---
.../devicetree/bindings/media/samsung-fimc.txt | 34 +++-
1 file changed, 26 insertions(+), 8 deletions(-)
diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt
b/Documentation/devicetree/bindings/media/samsung-fimc.txt
index 96312f6..dbd4020 100644
--- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
+++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
@@ -32,6 +32,21 @@ way around.
The 'camera' node must include at least one 'fimc' child node.
+Optional properties:
+
+- #clock-cells: from the common clock bindings (../clock/clock-bindings.txt),
+ must be 1. A clock provider is associated with the 'camera' node and it
should
+ be referenced by external sensors that use clocks provided by the SoC on
+ CAM_*_CLKOUT pins. The clock specifier cell stores an index of a clock.
+ The indices are 0, 1 for CAM_A_CLKOUT, CAM_B_CLKOUT clocks respectively.
+
+- clock-output-names: from the common clock bindings, should contain names of
+ clocks registered by the camera subsystem corresponding to CAM_A_CLKOUT,
+ CAM_B_CLKOUT output clocks respectively.
+
+Note: #clock-cells and clock-output-names are mandatory properties if external
+image sensor devices reference 'camera' device node as a clock provider.
+
'fimc' device nodes
---
@@ -97,8 +112,8 @@ Image sensor nodes
The sensor device nodes should be added to their control bus controller (e.g.
I2C0) nodes and linked to a port node in the csis or the parallel-ports node,
using the common video interfaces bindings, defined in video-interfaces.txt.
-The implementation of this bindings requires clock-frequency property to be
-present in the sensor device nodes.
+An optional clock-frequency property needs to be present in the sensor device
+nodes. Default value when this property is not present is 24 MHz.
Example:
@@ -114,7 +129,7 @@ Example:
vddio-supply = <...>;
clock-frequency = <2400>;
- clocks = <...>;
+ clocks = <&camera 1>;
clock-names = "mclk";
port {
@@ -135,7 +150,7 @@ Example:
vddio-supply = <...>;
clock-frequency = <2400>;
- clocks = <...>;
+ clocks = <&camera 0>;
clock-names = "mclk";
port {
@@ -149,12 +164,15 @@ Example:
camera {
compatible = "samsung,fimc", "simple-bus";
- #address-cells = <1>;
- #size-cells = <1>;
- status = "okay";
-
+ clocks = <&clock 132>, <&clock 133>;
+ clock-names = "sclk_cam0", "sclk_cam1";
+ #clock-cells = <1>;
+ clock-output-names = "cam_mclk_a", "cam_mclk_b";
pinctrl-names = "default";
pinctrl-0 = <&cam_port_a_clk_active>;
+ status = "okay";
+ #address-cells = <1>;
+ #size-cells = <1>;
/* parallel camera ports */
parallel-ports {
--
1.7.9.5
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