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48 lines
1.5 KiB
48 lines
1.5 KiB
# 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 binding |
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maintainers: |
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- Ulf Hansson <[email protected]> |
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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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sdhci0_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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