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