Thread (10 messages) 10 messages, 3 authors, 2015-02-11

[PATCH V4 1/4] mmc: core: Initial support for MMC power sequences

From: javier@dowhile0.org (Javier Martinez Canillas)
Date: 2015-01-28 10:17:22
Also in: linux-devicetree, linux-mmc

Hello Ulf,

On Mon, Jan 19, 2015 at 10:13 AM, Ulf Hansson [off-list ref] wrote:
System on chip designs may specify a specific MMC power sequence. To
successfully detect an (e)MMC/SD/SDIO card, that power sequence must
be followed while initializing the card.

To be able to handle these SOC specific power sequences, let's add a
MMC power sequence interface. It provides the following functions to
help the mmc core to deal with these power sequences.

mmc_pwrseq_alloc() - Invoked from mmc_of_parse(), to initialize data.
mmc_pwrseq_pre_power_on()- Invoked in the beginning of mmc_power_up().
mmc_pwrseq_post_power_on()- Invoked at the end in mmc_power_up().
mmc_pwrseq_power_off()- Invoked from mmc_power_off().
mmc_pwrseq_free() - Invoked from mmc_free_host(), to free data.

Each MMC power sequence provider will be responsible to implement a set
of callbacks. These callbacks mirrors the functions above.

This patch adds the skeleton, following patches will extend the core of
the MMC power sequence and add support for a specific simple MMC power
sequence.

Do note, since the mmc_pwrseq_alloc() is invoked from mmc_of_parse(),
host drivers needs to make use of this API to enable the support for
MMC power sequences. Moreover the MMC power sequence support depends on
CONFIG_OF.

Signed-off-by: Ulf Hansson <redacted>
---
Patch looks good to me and I could successfully get the SDIO wlan chip
in the Snow Chromebook after extending the pwrseq_simple driver so on
Exynos5250 Snow Chromebook:

Tested-by: Javier Martinez Canillas <redacted>
Reviewed-by: Javier Martinez Canillas <redacted>

Best regards,
Javier
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