Hi Adam,

On Tue, Jan 02, 2018 at 03:50:54PM +0000, Adam Thomson wrote:
> This commit adds a power_supply class instance to represent a
> PD source's voltage and current properties. This provides an
> interface for reading these properties from user-space or other
> drivers.
> 
> For PPS enabled Sources, this also provides write access to set
> the current and voltage and allows for swapping between standard
> PDO and PPS APDO.
> 
> As this represents a superset of the information provided in the
> fusb302 driver, the power_supply instance in that code is removed
> as part of this change, so reverting the commit titled
> 'typec: tcpm: Represent source supply through power_supply class'



> Signed-off-by: Adam Thomson <[email protected]>
> ---
>  .../ABI/testing/sysfs-class-power-tcpm-source-psy  |  92 ++++++++
>  drivers/usb/typec/Kconfig                          |   1 +
>  drivers/usb/typec/fusb302/Kconfig                  |   2 +-
>  drivers/usb/typec/fusb302/fusb302.c                |  63 +-----
>  drivers/usb/typec/tcpm.c                           | 233 
> ++++++++++++++++++++-
>  5 files changed, 328 insertions(+), 63 deletions(-)
>  create mode 100644 
> Documentation/ABI/testing/sysfs-class-power-tcpm-source-psy
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-power-tcpm-source-psy 
> b/Documentation/ABI/testing/sysfs-class-power-tcpm-source-psy
> new file mode 100644
> index 0000000..4986cba
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-power-tcpm-source-psy
> @@ -0,0 +1,92 @@
> +What:                /sys/class/power_supply/tcpm-source-psy/type
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-only property describes the main type of source supply.
> +     Type-C is a USB standard so this property always returns "USB".
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/connected_type
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-only property describes the type of source supply that is
> +     connected, if the supply is online. The value is always Type C
> +     unless a source has been attached which is identified as USB-PD capable.
> +
> +     Valid values:
> +             - "USB_TYPE_C"  : Type C connected supply, not UBS-PD capable
> +                               (default value)
> +             - "USB_PD"      : USB-PD capable source supply connected
> +             - "USB_PD_PPS"  : USB-PD PPS capable source supply connected
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/online
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-write property describes the online state of the source
> +     supply. When the value of this property is not 0, and the supply allows
> +     it, then it's possible to switch between online states (i.e. 1 -> 2,
> +     2 -> 1)
> +
> +     Valid values:
> +             - 0     : Offline, no source supply attached
> +             - 1     : Fixed Online, Type-C or USB-PD capable supply
> +                       attached, non-configurable current and voltage
> +                       properties in this state.
> +             - 2     : PPS Online, USB-PD PPS feature enabled, 'current_now'
> +                       and 'voltage_now' properties can be modified in this
> +                       state. Re-writing of this value again, once already
> +                       set, will re-request the same configured voltage and
> +                       current values. This can be used as a keep-alive for
> +                       the PPS connection.
> +                       [NOTE: This is value only selectable if
> +                        'connected_type' reports a value of "USB_PD_PPS"]
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/voltage_min
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-only property describes the minimum voltage the source supply
> +     can provide.
> +
> +     Value in microvolts.
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/voltage_max
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-only property describes the maximum voltage the source supply
> +     can provide.
> +
> +     Value in microvolts.
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/voltage_now
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-write property describes the voltage the source supply is
> +     providing now. This property can only be written to if the source supply
> +     is in online state '2' (PPS enabled), otherwise it's read-only
> +     information.
> +
> +     Value in microvolts.
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/current_max
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-only property describes the maximum current the source supply
> +     can provide.
> +
> +     Value in microamps.
> +
> +What:                /sys/class/power_supply/tcpm-source-psy/current_now
> +Date:                December 2017
> +Contact:     Adam Thomson <[email protected]>
> +Description:
> +     This read-write property describes the current the source supply can
> +     provide now. This property can only be written to if the source supply
> +     is in online state '2' (PPS enabled), otherwise it's read-only
> +     information.
> +
> +     Value in microamps.

I think those should be documented for the entire psy class, not just
for this driver.

> diff --git a/drivers/usb/typec/Kconfig b/drivers/usb/typec/Kconfig
> index bcb2744..1ef606d 100644
> --- a/drivers/usb/typec/Kconfig
> +++ b/drivers/usb/typec/Kconfig
> @@ -48,6 +48,7 @@ if TYPEC
>  config TYPEC_TCPM
>       tristate "USB Type-C Port Controller Manager"
>       depends on USB
> +     select POWER_SUPPLY

I'm a little bit uncomfortable with such a strong dependency on an
other subsystem that we may not always need, but let's see what
Guenter says.


Thanks,

-- 
heikki
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