e538d4b85b
When the power supply is shared with other peripherals the reset line can be wired in such a way that it can remain deasserted regardless of whether the supply is on or not. This is important as it can be used to avoid holding the controller in reset for extended periods of time when it remains powered, something which can lead to increased power consumption. Leaving reset deasserted also avoids leaking current through the reset circuitry pull-up resistors. Add a new 'no-reset-on-power-off' devicetree property which can be used by the OS to determine when reset needs to be asserted on power down. Note that this property can also be used when the supply cannot be turned off by the OS at all. Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20240507144821.12275-4-johan+linaro@kernel.org Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
81 lines
1.7 KiB
YAML
81 lines
1.7 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/input/elan,ekth6915.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Elan eKTH6915 touchscreen controller
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maintainers:
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- Douglas Anderson <dianders@chromium.org>
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description:
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Supports the Elan eKTH6915 touchscreen controller.
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This touchscreen controller uses the i2c-hid protocol with a reset GPIO.
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allOf:
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- $ref: /schemas/input/touchscreen/touchscreen.yaml#
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properties:
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compatible:
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oneOf:
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- items:
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- enum:
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- elan,ekth5015m
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- const: elan,ekth6915
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- const: elan,ekth6915
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reg:
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const: 0x10
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interrupts:
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maxItems: 1
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panel: true
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reset-gpios:
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description: Reset GPIO; not all touchscreens using eKTH6915 hook this up.
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no-reset-on-power-off:
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type: boolean
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description:
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Reset line is wired so that it can (and should) be left deasserted when
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the power supply is off.
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vcc33-supply:
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description: The 3.3V supply to the touchscreen.
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vccio-supply:
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description:
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The IO supply to the touchscreen. Need not be specified if this is the
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same as the 3.3V supply.
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required:
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- compatible
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- reg
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- interrupts
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- vcc33-supply
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additionalProperties: false
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examples:
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- |
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#include <dt-bindings/gpio/gpio.h>
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#include <dt-bindings/interrupt-controller/irq.h>
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i2c {
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#address-cells = <1>;
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#size-cells = <0>;
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touchscreen@10 {
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compatible = "elan,ekth5015m", "elan,ekth6915";
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reg = <0x10>;
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interrupt-parent = <&tlmm>;
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interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
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reset-gpios = <&tlmm 8 GPIO_ACTIVE_LOW>;
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vcc33-supply = <&pp3300_ts>;
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};
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};
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