Commit | Line | Data |
---|---|---|
726b6324 MS |
1 | * The simple eMMC hardware reset provider |
2 | ||
3 | The purpose of this driver is to perform standard eMMC hw reset | |
4 | procedure, as descibed by Jedec 4.4 specification. This procedure is | |
5 | performed just after MMC core enabled power to the given mmc host (to | |
6 | fix possible issues if bootloader has left eMMC card in initialized or | |
7 | unknown state), and before performing complete system reboot (also in | |
8 | case of emergency reboot call). The latter is needed on boards, which | |
9 | doesn't have hardware reset logic connected to emmc card and (limited or | |
10 | broken) ROM bootloaders are unable to read second stage from the emmc | |
11 | card if the card is left in unknown or already initialized state. | |
12 | ||
13 | Required 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 | ||
20 | Example: | |
21 | ||
22 | sdhci0_pwrseq { | |
23 | compatible = "mmc-pwrseq-emmc"; | |
24 | reset-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>; | |
25 | } |