Message ID | 20230729160857.6332-2-clamor95@gmail.com |
---|---|
State | Changes Requested, archived |
Headers | show |
Series | GPIO-based hotplug i2c bus | expand |
Context | Check | Description |
---|---|---|
robh/checkpatch | success | |
robh/patch-applied | success | |
robh/dtbs-check | warning | build log |
robh/dt-meta-schema | success |
On 29/07/2023 18:08, Svyatoslav Ryhel wrote: > Document device tree schema which describes hot-pluggable via GPIO > i2c bus. > A nit, subject: drop second/last, redundant "binding for". The "dt-bindings" prefix is already stating that these are bindings. > Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com> > --- > .../bindings/i2c/i2c-hotplug-gpio.yaml | 65 +++++++++++++++++++ > 1 file changed, 65 insertions(+) > create mode 100644 Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > new file mode 100644 > index 000000000000..21f2b74ca6c1 > --- /dev/null > +++ b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > @@ -0,0 +1,65 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/i2c/i2c-hotplug-gpio.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: GPIO detected hot-plugged I2C bus > + > +maintainers: > + - Michał Mirosław <mirq-linux@rere.qmqm.pl> > + > +description: > + Driver for hot-plugged I2C busses, where some devices on a bus > + are hot-pluggable and their presence is indicated by GPIO line. > + > +properties: > + compatible: > + items: Drop items. > + - const: i2c-hotplug-gpio > + > + '#address-cells': > + const: 1 > + > + '#size-cells': > + const: 0 Why do you need these two? You do not have any children. > + > + interrupts-extended: Just interrupts. > + minItems: 1 maxItems instead > + > + detect-gpios: > + maxItems: 1 > + > + i2c-parent: > + maxItems: 1 Where is the type defined? Why this has maxItems? Is it an array? > + > +required: > + - compatible > + - '#address-cells' > + - '#size-cells' > + - interrupts-extended > + - detect-gpios > + - i2c-parent > + > +unevaluatedProperties: false Without any $ref, this should be additionalProperties: false. > + > +examples: > + - | > + /* > + * Asus Transformers use I2C hotplug for attachable dock keyboard > + */ > + #include <dt-bindings/gpio/gpio.h> > + #include <dt-bindings/interrupt-controller/irq.h> > + > + i2c-dock { > + compatible = "i2c-hotplug-gpio"; > + > + #address-cells = <1>; > + #size-cells = <0>; > + > + interrupts-extended = <&gpio 164 IRQ_TYPE_EDGE_BOTH>; > + detect-gpios = <&gpio 164 GPIO_ACTIVE_LOW>; > + > + i2c-parent = <&gen2_i2c>; So do you expect here any children or not? > + }; > +... Best regards, Krzysztof
On Sat, Jul 29, 2023 at 07:08:56PM +0300, Svyatoslav Ryhel wrote: > Document device tree schema which describes hot-pluggable via GPIO > i2c bus. What's that? 'hot-pluggable via GPIO i2c bus' is not coherent. > > Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com> > --- > .../bindings/i2c/i2c-hotplug-gpio.yaml | 65 +++++++++++++++++++ > 1 file changed, 65 insertions(+) > create mode 100644 Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > new file mode 100644 > index 000000000000..21f2b74ca6c1 > --- /dev/null > +++ b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml > @@ -0,0 +1,65 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/i2c/i2c-hotplug-gpio.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: GPIO detected hot-plugged I2C bus > + > +maintainers: > + - Michał Mirosław <mirq-linux@rere.qmqm.pl> > + > +description: > + Driver for hot-plugged I2C busses, where some devices on a bus Bindings are for h/w, not a driver. > + are hot-pluggable and their presence is indicated by GPIO line. > + > +properties: > + compatible: > + items: > + - const: i2c-hotplug-gpio > + > + '#address-cells': > + const: 1 > + > + '#size-cells': > + const: 0 What are these for? You don't have any child nodes. > + > + interrupts-extended: > + minItems: 1 > + > + detect-gpios: > + maxItems: 1 > + > + i2c-parent: > + maxItems: 1 > + > +required: > + - compatible > + - '#address-cells' > + - '#size-cells' > + - interrupts-extended > + - detect-gpios > + - i2c-parent > + > +unevaluatedProperties: false > + > +examples: > + - | > + /* > + * Asus Transformers use I2C hotplug for attachable dock keyboard > + */ > + #include <dt-bindings/gpio/gpio.h> > + #include <dt-bindings/interrupt-controller/irq.h> > + > + i2c-dock { > + compatible = "i2c-hotplug-gpio"; > + > + #address-cells = <1>; > + #size-cells = <0>; > + > + interrupts-extended = <&gpio 164 IRQ_TYPE_EDGE_BOTH>; > + detect-gpios = <&gpio 164 GPIO_ACTIVE_LOW>; Looks like the same signal. You should only need one of them. Probably 'detect-gpios' as I guess you need to read the state of the line. > + > + i2c-parent = <&gen2_i2c>; Couldn't you just add 'detect-gpios' to the existing bus node? It's really part of that bus and there's not a separate bus. That would be a lot simpler. I suppose you want to instantiate a driver, but that's not DT's problem. Rob
On Fri, Aug 11, 2023 at 11:37:52AM -0600, Rob Herring wrote: > On Sat, Jul 29, 2023 at 07:08:56PM +0300, Svyatoslav Ryhel wrote: [...] > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml [...] > > + - | > > + /* > > + * Asus Transformers use I2C hotplug for attachable dock keyboard > > + */ > > + #include <dt-bindings/gpio/gpio.h> > > + #include <dt-bindings/interrupt-controller/irq.h> > > + > > + i2c-dock { > > + compatible = "i2c-hotplug-gpio"; > > + > > + #address-cells = <1>; > > + #size-cells = <0>; [...] > > + i2c-parent = <&gen2_i2c>; > > Couldn't you just add 'detect-gpios' to the existing bus node? It's > really part of that bus and there's not a separate bus. That would be a > lot simpler. I suppose you want to instantiate a driver, but that's not > DT's problem. Not a driver but a group of devices (possibly discovered dynamically) behind a passive gate (like e.g. PCA9517A with EN tied to a connector pin). It's not much different to a I2C gate or mux with a single child bus (i2c-mux-gpio that has only a single child). For ASUS Transformers with only the dock plugged-in it could work with a 'detect-gpios' extension (I'll take a look at how this way would work). I think there were also different attachments made you could connect instead of the dock. Best Regards Michał Mirosław
> Not a driver but a group of devices (possibly discovered dynamically) > behind a passive gate (like e.g. PCA9517A with EN tied to a connector pin). > It's not much different to a I2C gate or mux with a single child bus > (i2c-mux-gpio that has only a single child). I agree. To prevent the the bus from spikes when connecting / disconnecting something like PCA9517A should be in place. And this one can be considered a 1:1 mux. Just with the exception that Linux cannot control the gate, but can only react to changes to the enable pin. Can't we have a driver for the PCA9517 which gets interrupts when the enable pin changes and then adds / removes the child i2c adapter?
diff --git a/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml new file mode 100644 index 000000000000..21f2b74ca6c1 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml @@ -0,0 +1,65 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-hotplug-gpio.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: GPIO detected hot-plugged I2C bus + +maintainers: + - Michał Mirosław <mirq-linux@rere.qmqm.pl> + +description: + Driver for hot-plugged I2C busses, where some devices on a bus + are hot-pluggable and their presence is indicated by GPIO line. + +properties: + compatible: + items: + - const: i2c-hotplug-gpio + + '#address-cells': + const: 1 + + '#size-cells': + const: 0 + + interrupts-extended: + minItems: 1 + + detect-gpios: + maxItems: 1 + + i2c-parent: + maxItems: 1 + +required: + - compatible + - '#address-cells' + - '#size-cells' + - interrupts-extended + - detect-gpios + - i2c-parent + +unevaluatedProperties: false + +examples: + - | + /* + * Asus Transformers use I2C hotplug for attachable dock keyboard + */ + #include <dt-bindings/gpio/gpio.h> + #include <dt-bindings/interrupt-controller/irq.h> + + i2c-dock { + compatible = "i2c-hotplug-gpio"; + + #address-cells = <1>; + #size-cells = <0>; + + interrupts-extended = <&gpio 164 IRQ_TYPE_EDGE_BOTH>; + detect-gpios = <&gpio 164 GPIO_ACTIVE_LOW>; + + i2c-parent = <&gen2_i2c>; + }; +...
Document device tree schema which describes hot-pluggable via GPIO i2c bus. Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com> --- .../bindings/i2c/i2c-hotplug-gpio.yaml | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml