From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Peter Chen <peter.chen@nxp.com>
Cc: gregkh@linuxfoundation.org, stern@rowland.harvard.edu,
        ulf.hansson@linaro.org, broonie@kernel.org, sre@kernel.org,
        robh+dt@kernel.org, shawnguo@kernel.org, dbaryshkov@gmail.com,
        heiko@sntech.de, linux-arm-kernel@lists.infradead.org,
        p.zabel@pengutronix.de, devicetree@vger.kernel.org, pawel.moll@arm.com,
        mark.rutland@arm.com, linux-usb@vger.kernel.org, arnd@arndb.de,
        s.hauer@pengutronix.de, mail@maciej.szmigiero.name,
        troy.kisky@boundarydevices.com, festevam@gmail.com, oscar@naiandei.net,
        stephen.boyd@linaro.org, linux-pm@vger.kernel.org,
        stillcompiling@gmail.com, linux-kernel@vger.kernel.org,
        mka@chromium.org, vaibhav.hiremath@linaro.org
Subject: Re: [PATCH v8 0/8] power: add power sequence library
Date: Fri, 14 Oct 2016 14:09:31 +0200
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On Friday, October 14, 2016 10:59:47 AM Peter Chen wrote:
> Hi all,
> 
> This is a follow-up for my last power sequence framework patch set [1].
> According to Rob Herring and Ulf Hansson's comments[2]. The kinds of
> power sequence instances will be added at postcore_initcall, the match
> criteria is compatible string first, if the compatible string is not
> matched between dts and library, it will try to use generic power sequence.
> 	 
> The host driver just needs to call of_pwrseq_on/of_pwrseq_off
> if only one power sequence instance is needed, for more power sequences
> are used, using of_pwrseq_on_list/of_pwrseq_off_list instead (eg, USB hub driver).
> 
> In future, if there are special power sequence requirements, the special
> power sequence library can be created.
> 
> This patch set is tested on i.mx6 sabresx evk using a dts change, I use
> two hot-plug devices to simulate this use case, the related binding
> change is updated at patch [1/6], The udoo board changes were tested
> using my last power sequence patch set.[3]
> 
> Except for hard-wired MMC and USB devices, I find the USB ULPI PHY also
> need to power on itself before it can be found by ULPI bus.
> 
> [1] http://www.spinics.net/lists/linux-usb/msg142755.html
> [2] http://www.spinics.net/lists/linux-usb/msg143106.html
> [3] http://www.spinics.net/lists/linux-usb/msg142815.html
> 
> Changes for v8:
> - Allocate one extra pwrseq instance if pwrseq_get has succeed, it can avoid
>   preallocate instances problem which the number of instance is decided at
>   compile time, thanks for Heiko Stuebner's suggestion [Patch 2/8]
> - Delete pwrseq_compatible_sample.c which is the demo purpose to show compatible
>   match method. [Patch 2/8]
> - Add Maciej S. Szmigiero's tested-by. [Patch 7/8]
> 
> Changes for v7:
> - Create kinds of power sequence instance at postcore_initcall, and match
>   the instance with node using compatible string, the beneit of this is
>   the host driver doesn't need to consider which pwrseq instance needs
>   to be used, and pwrseq core will match it, however, it eats some memories
>   if less power sequence instances are used. [Patch 2/8]
> - Add pwrseq_compatible_sample.c to test match pwrseq using device_id. [Patch 2/8]
> - Fix the comments Vaibhav Hiremath adds for error path for clock and do not
>   use device_node for parameters at pwrseq_on. [Patch 2/8]
> - Simplify the caller to use power sequence, follows Alan's commnets [Patch 4/8]
> - Tested three pwrseq instances together using both specific compatible string and
>   generic libraries.
> 
> Changes for v6:
> - Add Matthias Kaehlcke's Reviewed-by and Tested-by. (patch [2/6])
> - Change chipidea core of_node assignment for coming user. (patch [5/6])
> - Applies Joshua Clayton's three dts changes for two boards,
>   the USB device's reg has only #address-cells, but without #size-cells.
> 
> Changes for v5:
> - Delete pwrseq_register/pwrseq_unregister, which is useless currently
> - Fix the linker error when the pwrseq user is compiled as module
> 
> Changes for v4:
> - Create the patch on next-20160722 
> - Fix the of_node is not NULL after chipidea driver is unbinded [Patch 5/6]
> - Using more friendly wait method for reset gpio [Patch 2/6]
> - Support multiple input clocks [Patch 2/6]
> - Add Rob Herring's ack for DT changes
> - Add Joshua Clayton's Tested-by
> 
> Changes for v3:
> - Delete "power-sequence" property at binding-doc, and change related code
>   at both library and user code.
> - Change binding-doc example node name with Rob's comments
> - of_get_named_gpio_flags only gets the gpio, but without setting gpio flags,
>   add additional code request gpio with proper gpio flags
> - Add Philipp Zabel's Ack and MAINTAINER's entry
> 
> Changes for v2:
> - Delete "pwrseq" prefix and clock-names for properties at dt binding
> - Should use structure not but its pointer for kzalloc
> - Since chipidea core has no of_node, let core's of_node equals glue
>   layer's at core's probe
> 
> Joshua Clayton (2):
>   ARM: dts: imx6qdl: Enable usb node children with <reg>
>   ARM: dts: imx6q-evi: Fix onboard hub reset line
> 
> Peter Chen (6):
>   binding-doc: power: pwrseq-generic: add binding doc for generic power
>     sequence library
>   power: add power sequence library
>   binding-doc: usb: usb-device: add optional properties for power
>     sequence
>   usb: core: add power sequence handling for USB devices
>   usb: chipidea: let chipidea core device of_node equal's glue layer
>     device of_node
>   ARM: dts: imx6qdl-udoo.dtsi: fix onboard USB HUB property
> 
>  .../bindings/power/pwrseq/pwrseq-generic.txt       |  48 ++++++
>  .../devicetree/bindings/usb/usb-device.txt         |  10 +-
>  MAINTAINERS                                        |   9 +
>  arch/arm/boot/dts/imx6q-evi.dts                    |  25 +--
>  arch/arm/boot/dts/imx6qdl-udoo.dtsi                |  26 ++-
>  arch/arm/boot/dts/imx6qdl.dtsi                     |   6 +
>  drivers/power/Kconfig                              |   1 +
>  drivers/power/Makefile                             |   1 +
>  drivers/power/pwrseq/Kconfig                       |  19 ++
>  drivers/power/pwrseq/Makefile                      |   2 +
>  drivers/power/pwrseq/core.c                        | 191 +++++++++++++++++++++
>  drivers/power/pwrseq/pwrseq_generic.c              | 183 ++++++++++++++++++++
>  drivers/usb/chipidea/core.c                        |  27 ++-
>  drivers/usb/core/hub.c                             |  41 ++++-
>  drivers/usb/core/hub.h                             |   1 +
>  include/linux/power/pwrseq.h                       |  72 ++++++++
>  16 files changed, 621 insertions(+), 41 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
>  create mode 100644 drivers/power/pwrseq/Kconfig
>  create mode 100644 drivers/power/pwrseq/Makefile
>  create mode 100644 drivers/power/pwrseq/core.c
>  create mode 100644 drivers/power/pwrseq/pwrseq_generic.c
>  create mode 100644 include/linux/power/pwrseq.h

Meta question: Who's the maintainer you are targetting this at?

Thanks,
Rafael