bindings/i2c/i2c-arb-gpio-challenge.yaml

1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
3 ---
4 $id: http://devicetree.org/schemas/i2c/i2c-arb-gpio-challenge.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: GPIO-based I2C Arbitration Using a Challenge & Response Mechanism
10   - Doug Anderson <dianders@chromium.org>
11   - Peter Rosin <peda@axentia.se>
15   the master of an I2C bus in a multimaster situation.
18   standard I2C multi-master rules.  Using GPIOs is generally useful in the case
23    * It is nonstandard (not using standard I2C multimaster)
25      problems (hard to tell if i2c issues were caused by one master, another,
30   others can see. These are all active low with pull-ups enabled.  We'll
47   6. Go back to 1 (until retry time has expired).
51     const: i2c-arb-gpio-challenge
53   i2c-parent:
56       The I2C bus that this multiplexer's master-side port is connected to.
58   our-claim-gpios:
63   slew-delay-us:
68   their-claim-gpios:
75   wait-free-us:
80   wait-retry-us:
85   i2c-arb:
87     $ref: /schemas/i2c/i2c-controller.yaml
90       I2C arbitration bus node.
93   - compatible
94   - i2c-arb
95   - our-claim-gpios
96   - their-claim-gpios
101   - |
102     #include <dt-bindings/gpio/gpio.h>
103     #include <dt-bindings/interrupt-controller/irq.h>
105     i2c-arbitrator {
106         compatible = "i2c-arb-gpio-challenge";
107         i2c-parent = <&i2c_4>;
109         our-claim-gpios = <&gpf0 3 GPIO_ACTIVE_LOW>;
110         their-claim-gpios = <&gpe0 4 GPIO_ACTIVE_LOW>;
111         slew-delay-us = <10>;
112         wait-retry-us = <3000>;
113         wait-free-us = <50000>;
115         i2c-arb {
116             #address-cells = <1>;
117             #size-cells = <0>;
119             sbs-battery@b {
120                 compatible = "sbs,sbs-battery";
122                 sbs,poll-retry-count = <1>;
125             embedded-controller@1e {
126                 compatible = "google,cros-ec-i2c";
129                 interrupt-parent = <&gpx1>;
130                 pinctrl-names = "default";
131                 pinctrl-0 = <&ec_irq>;
132                 wakeup-source;