Some devices, like WiFi chipsets AP6335 require a specific power-up sequence ordering before being used. You must enable the vqmmc power supply and wait until it reaches its minimum voltage, gate the clock and wait at least two cycles and then assert the reset line. See DS 1/ Currently, there is no generic manner for doing this with pwrseq_simple. This set of patches proposes an approach to support this use case. It is related to the old patch 2/ 1. http://www.t-firefly.com/download/firefly-rk3288/hardware/AP6335%20datasheet_V1.3_02102014.pdf 2. http://lists.infradead.org/pipermail/linux-arm-kernel/2017-March/490681.html Romain Perier (4): mmc: core: Add post_ios_power_on callback for power sequences mmc: pwrseq-simple: Add optional op. for post_ios_power_on callback mmc: pwrseq_simple: Add an optional pre-power-on-delay arm: dts: rockchip: Enable post_ios_power_on and pre-power-on-delay-ms .../devicetree/bindings/mmc/mmc-pwrseq-simple.txt | 2 ++ arch/arm/boot/dts/rk3288-rock2-square.dts | 2 ++ drivers/mmc/core/core.c | 1 + drivers/mmc/core/pwrseq.c | 8 ++++++++ drivers/mmc/core/pwrseq.h | 2 ++ drivers/mmc/core/pwrseq_simple.c | 21 ++++++++++++++++++++- 6 files changed, 35 insertions(+), 1 deletion(-) -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
