[PATCH v3 00/12] usb/mmc/power: Generic power sequence (and fix USB/LAN when TFTP booting)

[Heiko Stübner]

Hi,

Am Mittwoch, 1. Juni 2016, 10:02:09 schrieb Krzysztof Kozlowski:
> My third approach for a USB power sequence which fixes usb3503+lan
> on Odroid U3 board if it was initialized by bootloader
> (e.g. for TFTP boot).

I was just tackling a similar bringup problem regarding an embedded usb hub 
and usb-sata bridge and stumbled upon this series.

While on my (rockchip-)boards it's always "just" a reset pin that needs 
handling, this series looks like it would solve exactly that problem in a very 
nice way.

So while I cannot provide any meaningful insight right now, it would be cool 
if you could keep me in the loop, as I'm really looking forward to this series 
progressing.


Thanks
Heiko


> Changes since v2
> ================
> 1. Add Javier's reviewed-by tags. Address some comments.
> 2. Re-use existing properties for GPIOs etc by pwrseq-simple
>    driver.  New property is still added: "power-sequence".
>    I tried to address and do according to Rob's comments.
> 
>    Please look at patch 6/12 ("power: pwrseq: simple: Add support
>    for regulator and generic property") for bindings and the
>    new code around matching "power-sequence" property.
> 
> 3. I marked the usb code as "EXAMPLE" because that part
>    is left to Peter Chen.
> 
> 
> Problem
> =======
> When Odroid U3 (usb3503 + smsc95xx + max77686) boots from network (TFTP),
> the usb3503 and LAN smsc95xx do not show up in "lsusb". Hard-reset
> is required, e.g. by suspend to RAM. The actual TFTP boot does
> not have to happen. Just "usb start" from U-Boot is sufficient.
> 
> From the schematics, the regulator is a supply only to LAN, however
> without toggling it off/on, the usb3503 hub won appear neither.
> 
> 
> Solution
> ========
> This is very similar to the MMC pwrseq behavior so the idea is to:
> 1. Move MMC pwrseq drivers to generic place,
> 2. Extend the pwrseq-simple with regulator toggling,
> 3. Add support to USB hub and port core for pwrseq,
> 4. Toggle the regulator when needed.
> 
> Best regards,
> Krzysztof
> 
> Krzysztof Kozlowski (12):
>   power/mmc: Move pwrseq drivers to power/pwrseq
>   MAINTAINERS: Retain Ulf Hansson as the same maintainer of pwrseq
>   power: pwrseq: Enable COMPILE_TEST for drivers
>   power: pwrseq: Remove mmc prefix from mmc_pwrseq
>   power: pwrseq: Generalize mmc_pwrseq operations by removing mmc prefix
>   power: pwrseq: simple: Add support for regulator and generic property
>   power: pwrseq: Add support for USB hubs with external power
>   usb: hub: Handle deferred probe
>   EXAMPLE CODE: usb: port: Parse pwrseq phandle from Device Tree
>   EXAMPLE CODE: usb: hub: Power sequence the ports on activation
>   ARM: dts: exynos: Switch the buck8 to GPIO mode on Odroid U3
>   ARM: dts: exynos: Fix LAN and HUB after bootloader initialization on
>     Odroid U3
> 
>  .../pwrseq/pwrseq-emmc.txt}                        |   0
>  .../pwrseq/pwrseq-simple.txt}                      |  29 +++-
>  MAINTAINERS                                        |   9 ++
>  arch/arm/boot/dts/exynos4412-odroidu3.dts          |   5 +
>  drivers/mmc/Kconfig                                |   2 -
>  drivers/mmc/core/Makefile                          |   3 -
>  drivers/mmc/core/core.c                            |   8 +-
>  drivers/mmc/core/host.c                            |   2 +-
>  drivers/mmc/core/pwrseq.c                          | 110 ---------------
>  drivers/mmc/core/pwrseq.h                          |  52 -------
>  drivers/power/Kconfig                              |   1 +
>  drivers/power/Makefile                             |   1 +
>  drivers/{mmc/core => power/pwrseq}/Kconfig         |  22 ++-
>  drivers/power/pwrseq/Makefile                      |   3 +
>  drivers/power/pwrseq/pwrseq.c                      | 153
> +++++++++++++++++++++ drivers/{mmc/core => power/pwrseq}/pwrseq_emmc.c   | 
> 17 +--
>  drivers/{mmc/core => power/pwrseq}/pwrseq_simple.c | 110 ++++++++++++---
>  drivers/usb/core/hub.c                             |  16 ++-
>  drivers/usb/core/hub.h                             |   3 +
>  drivers/usb/core/port.c                            |  15 ++
>  include/linux/mmc/host.h                           |   4 +-
>  include/linux/pwrseq.h                             |  63 +++++++++
>  22 files changed, 414 insertions(+), 214 deletions(-)
>  rename Documentation/devicetree/bindings/{mmc/mmc-pwrseq-emmc.txt =>
> power/pwrseq/pwrseq-emmc.txt} (100%) rename
> Documentation/devicetree/bindings/{mmc/mmc-pwrseq-simple.txt =>
> power/pwrseq/pwrseq-simple.txt} (53%) delete mode 100644
> drivers/mmc/core/pwrseq.c
>  delete mode 100644 drivers/mmc/core/pwrseq.h
>  rename drivers/{mmc/core => power/pwrseq}/Kconfig (60%)
>  create mode 100644 drivers/power/pwrseq/Makefile
>  create mode 100644 drivers/power/pwrseq/pwrseq.c
>  rename drivers/{mmc/core => power/pwrseq}/pwrseq_emmc.c (88%)
>  rename drivers/{mmc/core => power/pwrseq}/pwrseq_simple.c (52%)
>  create mode 100644 include/linux/pwrseq.h