During power off, after the GPIO pin has been asserted, some devices like
the Wifi chip from TI, Wl18xx, needs a delay before the host continues with
clock gating and turning off regulators as to follow a graceful shutdown
sequence.
Therefore invent an optional power-off-delay-us DT binding for
mmc-pwrseq-simple, to allow us to support this constraint.
Cc: devicetree@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mmc@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Some devices need a while to boot their firmware after providing clks /
de-asserting resets before they are ready to receive sdio commands.
This commits adds a post-power-on-delay-ms devicetree property to
mmc-pwrseq-simple for use with such devices.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Some WLAN chips attached to a SDIO interface, need an external clock
to be operational. Since this is very common, extend the simple MMC
power sequence DT binding to support an optional clock.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Many SDIO/MMC attached WLAN chips need more than one ping for their reset
sequence. Extend the pwrseq_simple binding to support more than one pin.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
To support SOCs which specifies specific MMC power sequences, document
some MMC DT bindings to be able to describe these hardwares.
Let's also document bindings for a simple MMC power sequence provider,
which purpose is to support a set of common properties between various
SOCs.
In this initial step, let's also document a top level description of
the MMC power sequence and describe the compatible string used for the
simple MMC power sequence provider.
The simple MMC power sequence provider will initially support a reset
GPIO. From several earlier posted patches, it's clear that such
hardware exists. Especially some WLAN chips which are attached to an
SDIO interface may use a GPIO reset.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Ulf Hansson