1* The simple eMMC hardware reset provider 2 3The purpose of this driver is to perform standard eMMC hw reset 4procedure, as described by Jedec 4.4 specification. This procedure is 5performed just after MMC core enabled power to the given mmc host (to 6fix possible issues if bootloader has left eMMC card in initialized or 7unknown state), and before performing complete system reboot (also in 8case of emergency reboot call). The latter is needed on boards, which 9doesn't have hardware reset logic connected to emmc card and (limited or 10broken) ROM bootloaders are unable to read second stage from the emmc 11card if the card is left in unknown or already initialized state. 12 13Required properties: 14- compatible : contains "mmc-pwrseq-emmc". 15- reset-gpios : contains a GPIO specifier. The reset GPIO is asserted 16 and then deasserted to perform eMMC card reset. To perform 17 reset procedure as described in Jedec 4.4 specification, the 18 gpio line should be defined as GPIO_ACTIVE_LOW. 19 20Example: 21 22 sdhci0_pwrseq { 23 compatible = "mmc-pwrseq-emmc"; 24 reset-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>; 25 } 26