49 lines
1.5 KiB
YAML
49 lines
1.5 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/mmc/mmc-pwrseq-emmc.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Simple eMMC hardware reset provider
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maintainers:
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- Ulf Hansson <ulf.hansson@linaro.org>
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description:
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The purpose of this driver is to perform standard eMMC hw reset
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procedure, as described by Jedec 4.4 specification. This procedure is
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performed just after MMC core enabled power to the given mmc host (to
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fix possible issues if bootloader has left eMMC card in initialized or
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unknown state), and before performing complete system reboot (also in
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case of emergency reboot call). The latter is needed on boards, which
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doesn't have hardware reset logic connected to emmc card and (limited or
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broken) ROM bootloaders are unable to read second stage from the emmc
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card if the card is left in unknown or already initialized state.
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properties:
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compatible:
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const: mmc-pwrseq-emmc
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reset-gpios:
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minItems: 1
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description:
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contains a GPIO specifier. The reset GPIO is asserted
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and then deasserted to perform eMMC card reset. To perform
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reset procedure as described in Jedec 4.4 specification, the
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gpio line should be defined as GPIO_ACTIVE_LOW.
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required:
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- compatible
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- reset-gpios
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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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pwrseq {
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compatible = "mmc-pwrseq-emmc";
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reset-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;
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};
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...
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