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1# SPDX-License-Identifier: GPL-2.02%YAML 1.23---4$id: http://devicetree.org/schemas/mmc/mmc-pwrseq-emmc.yaml#5$schema: http://devicetree.org/meta-schemas/core.yaml#6 7title: Simple eMMC hardware reset provider8 9maintainers:10 - Ulf Hansson <ulf.hansson@linaro.org>11 12description:13 The purpose of this driver is to perform standard eMMC hw reset14 procedure, as described by Jedec 4.4 specification. This procedure is15 performed just after MMC core enabled power to the given mmc host (to16 fix possible issues if bootloader has left eMMC card in initialized or17 unknown state), and before performing complete system reboot (also in18 case of emergency reboot call). The latter is needed on boards, which19 doesn't have hardware reset logic connected to emmc card and (limited or20 broken) ROM bootloaders are unable to read second stage from the emmc21 card if the card is left in unknown or already initialized state.22 23properties:24 compatible:25 const: mmc-pwrseq-emmc26 27 reset-gpios:28 minItems: 129 description:30 contains a GPIO specifier. The reset GPIO is asserted31 and then deasserted to perform eMMC card reset. To perform32 reset procedure as described in Jedec 4.4 specification, the33 gpio line should be defined as GPIO_ACTIVE_LOW.34 35required:36 - compatible37 - reset-gpios38 39additionalProperties: false40 41examples:42 - |43 #include <dt-bindings/gpio/gpio.h>44 pwrseq {45 compatible = "mmc-pwrseq-emmc";46 reset-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;47 };48...49