| Message ID | 20211013204424.10961-2-kabel@kernel.org |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | [1/3] dt-bindings: leds: Deprecate `linux,default-trigger` property | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success | |
| robh/dt-meta-schema | fail | build log |
On Wed, 13 Oct 2021 22:44:23 +0200, Marek Behún wrote: > Some RJ-45 connectors have LEDs wired in the following way: > > LED1 > +--|>|--+ > | | > A---+--|<|--+---B > LED2 > > With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the > polarity turns LED1 OFF and LED2 ON. > > So these LEDs exclude each other. > > Add new `excludes` property to the LED binding. The property is a > phandle-array to all the other LEDs that are excluded by this LED. > > Signed-off-by: Marek Behún <kabel@kernel.org> > --- > Documentation/devicetree/bindings/leds/common.yaml | 8 ++++++++ > 1 file changed, 8 insertions(+) > My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check' on your patch (DT_CHECKER_FLAGS is new in v5.13): yamllint warnings/errors: ./Documentation/devicetree/bindings/leds/common.yaml:66:7: [error] syntax error: could not find expected ':' (syntax) dtschema/dtc warnings/errors: make[1]: *** Deleting file 'Documentation/devicetree/bindings/leds/common.example.dts' Traceback (most recent call last): File "/usr/local/bin/dt-extract-example", line 45, in <module> binding = yaml.load(open(args.yamlfile, encoding='utf-8').read()) File "/usr/local/lib/python3.8/dist-packages/ruamel/yaml/main.py", line 434, in load return constructor.get_single_data() File "/usr/local/lib/python3.8/dist-packages/ruamel/yaml/constructor.py", line 120, in get_single_data node = self.composer.get_single_node() File "_ruamel_yaml.pyx", line 706, in _ruamel_yaml.CParser.get_single_node File "_ruamel_yaml.pyx", line 724, in _ruamel_yaml.CParser._compose_document File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node File "_ruamel_yaml.pyx", line 889, in _ruamel_yaml.CParser._compose_mapping_node File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node File "_ruamel_yaml.pyx", line 889, in _ruamel_yaml.CParser._compose_mapping_node File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node File "_ruamel_yaml.pyx", line 889, in _ruamel_yaml.CParser._compose_mapping_node File "_ruamel_yaml.pyx", line 775, in _ruamel_yaml.CParser._compose_node File "_ruamel_yaml.pyx", line 891, in _ruamel_yaml.CParser._compose_mapping_node File "_ruamel_yaml.pyx", line 904, in _ruamel_yaml.CParser._parse_next_event ruamel.yaml.scanner.ScannerError: while scanning a simple key in "<unicode string>", line 65, column 7 could not find expected ':' in "<unicode string>", line 66, column 7 make[1]: *** [Documentation/devicetree/bindings/Makefile:20: Documentation/devicetree/bindings/leds/common.example.dts] Error 1 make[1]: *** Waiting for unfinished jobs.... schemas/leds/common.yaml: ignoring, error parsing file schemas/leds/common.yaml: ignoring, error parsing file ./Documentation/devicetree/bindings/leds/common.yaml: while scanning a simple key in "<unicode string>", line 65, column 7 could not find expected ':' in "<unicode string>", line 66, column 7 /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/leds/common.yaml: ignoring, error parsing file warning: no schema found in file: ./Documentation/devicetree/bindings/leds/common.yaml make: *** [Makefile:1441: dt_binding_check] Error 2 doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/patch/1540615 This check can fail if there are any dependencies. The base for a patch series is generally the most recent rc1. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit.
Hi! > Some RJ-45 connectors have LEDs wired in the following way: > > LED1 > +--|>|--+ > | | > A---+--|<|--+---B > LED2 > > With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the > polarity turns LED1 OFF and LED2 ON. > > So these LEDs exclude each other. > > Add new `excludes` property to the LED binding. The property is a > phandle-array to all the other LEDs that are excluded by this LED. I don't think this belongs to the LED binding. This is controller limitation, and the driver handling the controller needs to know about it... so it does not need to learn that from the LED binding. Best regards, Pavel
On Thu, 14 Oct 2021 12:29:18 +0200 Pavel Machek <pavel@ucw.cz> wrote: > Hi! > > > Some RJ-45 connectors have LEDs wired in the following way: > > > > LED1 > > +--|>|--+ > > | | > > A---+--|<|--+---B > > LED2 > > > > With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the > > polarity turns LED1 OFF and LED2 ON. > > > > So these LEDs exclude each other. > > > > Add new `excludes` property to the LED binding. The property is a > > phandle-array to all the other LEDs that are excluded by this LED. > > I don't think this belongs to the LED binding. > > This is controller limitation, and the driver handling the controller > needs to know about it... so it does not need to learn that from the > LED binding. It's not necessarily a controller limitation, rather a limitation of the board (or ethernet connector, in the case of LEDs on an ethernet connector). But I guess we could instead document this property in the ethernet PHY controller binding for a given PHY. Marek
Hei hei, Am Thu, Oct 14, 2021 at 12:43:09PM +0200 schrieb Marek Behún: > On Thu, 14 Oct 2021 12:29:18 +0200 > Pavel Machek <pavel@ucw.cz> wrote: > > > Hi! > > > > > Some RJ-45 connectors have LEDs wired in the following way: > > > > > > LED1 > > > +--|>|--+ > > > | | > > > A---+--|<|--+---B > > > LED2 > > > > > > With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the > > > polarity turns LED1 OFF and LED2 ON. > > > > > > So these LEDs exclude each other. > > > > > > Add new `excludes` property to the LED binding. The property is a > > > phandle-array to all the other LEDs that are excluded by this LED. > > > > I don't think this belongs to the LED binding. > > > > This is controller limitation, and the driver handling the controller > > needs to know about it... so it does not need to learn that from the > > LED binding. > > It's not necessarily a controller limitation, rather a limitation of > the board (or ethernet connector, in the case of LEDs on an ethernet > connector). Such LEDs are not limited to PHYs or ethernet connectors. There is hardware with such dual color LEDs connected to GPIO pins (either directly to the SoC or through some GPIO expander like an 74hc595 shift register). That mail points to such hardware: https://www.spinics.net/lists/linux-leds/msg11847.html I asked about how this can be modelled back in 2019 and it was also discussed last year: https://www.spinics.net/lists/linux-leds/msg11665.html https://lore.kernel.org/linux-leds/2315048.uTtSMl1LR1@ada/ The "solution" back when I first asked was treating them as ordinary GPIO-LEDs and ignore the "exclusion topic" which means in practice the LED goes OFF if both pins are ON (high) at the same time, which works well enough in practice. > But I guess we could instead document this property in the ethernet PHY > controller binding for a given PHY. Because such LEDs are not restricted to ethernet PHYs, but can also be used with GPIOs from the hardware point of view, I would not put it there. Furthermore I would not view this as a restriction of the gpio-leds controller, but it's a property of the LEDs itself or the way they are wired to the board. This could (or should as Pavel suggested back in 2019) be put to a new driver, at least for the GPIO case, but it would need some kind of new binding anyways. With that in mind I consider the proposed binding to be well comprehensible for a human reader/writer. I'm sorry, I did not have leisure time to implement such a driver yet. Breadboard hardware for that still waiting in the drawer. :-/ Greets Alex
On Thu, 14 Oct 2021 13:30:39 +0200 Alexander Dahl <ada@thorsis.com> wrote: > Hei hei, > > Am Thu, Oct 14, 2021 at 12:43:09PM +0200 schrieb Marek Behún: > > On Thu, 14 Oct 2021 12:29:18 +0200 > > Pavel Machek <pavel@ucw.cz> wrote: > > > > > Hi! > > > > > > > Some RJ-45 connectors have LEDs wired in the following way: > > > > > > > > LED1 > > > > +--|>|--+ > > > > | | > > > > A---+--|<|--+---B > > > > LED2 > > > > > > > > With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting > > > > the polarity turns LED1 OFF and LED2 ON. > > > > > > > > So these LEDs exclude each other. > > > > > > > > Add new `excludes` property to the LED binding. The property is > > > > a phandle-array to all the other LEDs that are excluded by this > > > > LED. > > > > > > I don't think this belongs to the LED binding. > > > > > > This is controller limitation, and the driver handling the > > > controller needs to know about it... so it does not need to learn > > > that from the LED binding. > > > > It's not necessarily a controller limitation, rather a limitation of > > the board (or ethernet connector, in the case of LEDs on an ethernet > > connector). > > Such LEDs are not limited to PHYs or ethernet connectors. There is > hardware with such dual color LEDs connected to GPIO pins (either > directly to the SoC or through some GPIO expander like an 74hc595 > shift register). That mail points to such hardware: > > https://www.spinics.net/lists/linux-leds/msg11847.html > > I asked about how this can be modelled back in 2019 and it was also > discussed last year: > > https://www.spinics.net/lists/linux-leds/msg11665.html > https://lore.kernel.org/linux-leds/2315048.uTtSMl1LR1@ada/ > > The "solution" back when I first asked was treating them as ordinary > GPIO-LEDs and ignore the "exclusion topic" which means in practice the > LED goes OFF if both pins are ON (high) at the same time, which works > well enough in practice. > > > But I guess we could instead document this property in the ethernet > > PHY controller binding for a given PHY. > > Because such LEDs are not restricted to ethernet PHYs, but can also be > used with GPIOs from the hardware point of view, I would not put it > there. > > Furthermore I would not view this as a restriction of the gpio-leds > controller, but it's a property of the LEDs itself or the way they are > wired to the board. > > This could (or should as Pavel suggested back in 2019) be put to a new > driver, at least for the GPIO case, but it would need some kind of new > binding anyways. With that in mind I consider the proposed binding to > be well comprehensible for a human reader/writer. > > I'm sorry, I did not have leisure time to implement such a driver yet. > Breadboard hardware for that still waiting in the drawer. :-/ That's why I think we need the `excludes` property. On the sw side, it should work like this: $ cd /sys/class/leds $ echo 1 >LED1/brightness $ cat LED1/brightness LED2/brightness 1 0 $ echo 1 >LED2/brightness $ cat LED1/brightness LED2/brightness 0 1 The drivers could also implement brightness_hw_changed for these LEDs. Marek
diff --git a/Documentation/devicetree/bindings/leds/common.yaml b/Documentation/devicetree/bindings/leds/common.yaml index a19acc781e89..03759d2e125a 100644 --- a/Documentation/devicetree/bindings/leds/common.yaml +++ b/Documentation/devicetree/bindings/leds/common.yaml @@ -59,6 +59,14 @@ properties: deprecated - use 'function' and 'color' properties instead. function-enumerator has no effect when this property is present. + excludes: + description: + List of LEDs that are excluded by this LED: if this LED is ON, the others + must be OFF. This is mostly the case when there are two LEDs connected in + parallel, but inversely: inverting the polarity of the source turns one + LED ON while the other OFF. There are RJ-45 connectors with such wiring. + $ref: /schemas/types.yaml#/definitions/phandle-array + default-state: description: The initial state of the LED. If the LED is already on or off and the
Some RJ-45 connectors have LEDs wired in the following way: LED1 +--|>|--+ | | A---+--|<|--+---B LED2 With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the polarity turns LED1 OFF and LED2 ON. So these LEDs exclude each other. Add new `excludes` property to the LED binding. The property is a phandle-array to all the other LEDs that are excluded by this LED. Signed-off-by: Marek Behún <kabel@kernel.org> --- Documentation/devicetree/bindings/leds/common.yaml | 8 ++++++++ 1 file changed, 8 insertions(+)