Re: [PATCH v4 4/6] platform/x86: ayaneo-ec: Add controller power and modules attributes

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Wed, 12 Nov 2025, Antheas Kapenekakis wrote:

> On Wed, 12 Nov 2025 at 13:34, Ilpo Järvinen
> <ilpo.jarvinen@linux.intel.com> wrote:
> >
> > On Tue, 11 Nov 2025, Antheas Kapenekakis wrote:
> >
> > > On Tue, 11 Nov 2025 at 14:41, Ilpo Järvinen
> > > <ilpo.jarvinen@linux.intel.com> wrote:
> > > >
> > > > On Mon, 10 Nov 2025, Antheas Kapenekakis wrote:
> > > >
> > > > > The Ayaneo 3 features hot-swappable controller modules. The ejection
> > > > > and management is done through HID. However, after ejecting the modules,
> > > > > the controller needs to be power cycled via the EC to re-initialize.
> > > > >
> > > > > For this, the EC provides a variable that holds whether the left or
> > > > > right modules are connected, and a power control register to turn
> > > > > the controller on or off. After ejecting the modules, the controller
> > > > > should be turned off. Then, after both modules are reinserted,
> > > > > the controller may be powered on again to re-initialize.
> > > > >
> > > > > This patch introduces two new sysfs attributes:
> > > > >  - `controller_modules`: a read-only attribute that indicates whether
> > > > >    the left and right modules are connected (none, left, right, both).
> > > > >  - `controller_power`: a read-write attribute that allows the user
> > > > >    to turn the controller on or off (with '1'/'0').
> > > > >
> > > > > Therefore, after ejection is complete, userspace can power off the
> > > > > controller, then wait until both modules have been reinserted
> > > > > (`controller_modules` will return 'both') to turn on the controller.
> > > > >
> > > > > Reviewed-by: Armin Wolf <W_Armin@gmx.de>
> > > > > Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
> > > > > ---
> > > > >  .../ABI/testing/sysfs-platform-ayaneo-ec      |  19 ++++
> > > > >  MAINTAINERS                                   |   1 +
> > > > >  drivers/platform/x86/ayaneo-ec.c              | 106 ++++++++++++++++++
> > > > >  3 files changed, 126 insertions(+)
> > > > >  create mode 100644 Documentation/ABI/testing/sysfs-platform-ayaneo-ec
> > > > >
> > > > > diff --git a/Documentation/ABI/testing/sysfs-platform-ayaneo-ec b/Documentation/ABI/testing/sysfs-platform-ayaneo-ec
> > > > > new file mode 100644
> > > > > index 000000000000..4cffbf5fc7ca
> > > > > --- /dev/null
> > > > > +++ b/Documentation/ABI/testing/sysfs-platform-ayaneo-ec
> > > > > @@ -0,0 +1,19 @@
> > > > > +What:                /sys/devices/platform/ayaneo-ec/controller_power
> > > > > +Date:                Nov 2025
> > > > > +KernelVersion:       6.19
> > > > > +Contact:     "Antheas Kapenekakis" <lkml@antheas.dev>
> > > > > +Description:
> > > > > +             Current controller power state. Allows turning on and off
> > > > > +             the controller power (e.g. for power savings). Write 1 to
> > > > > +             turn on, 0 to turn off. File is readable and writable.
> > > > > +
> > > > > +What:                /sys/devices/platform/ayaneo-ec/controller_modules
> > > > > +Date:                Nov 2025
> > > > > +KernelVersion:       6.19
> > > > > +Contact:     "Antheas Kapenekakis"  <lkml@antheas.dev>
> > > > > +Description:
> > > > > +             Shows which controller modules are currently connected to
> > > > > +             the device. Possible values are "left", "right" and "both".
> > > > > +             File is read-only. The Windows software for this device
> > > > > +             will only set controller power to 1 if both module sides
> > > > > +             are connected (i.e. this file returns "both").
> > > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > > index c5bf7207c45f..f8ab009b6224 100644
> > > > > --- a/MAINTAINERS
> > > > > +++ b/MAINTAINERS
> > > > > @@ -4196,6 +4196,7 @@ AYANEO PLATFORM EC DRIVER
> > > > >  M:   Antheas Kapenekakis <lkml@antheas.dev>
> > > > >  L:   platform-driver-x86@vger.kernel.org
> > > > >  S:   Maintained
> > > > > +F:   Documentation/ABI/testing/sysfs-platform-ayaneo
> > > > >  F:   drivers/platform/x86/ayaneo-ec.c
> > > > >
> > > > >  AZ6007 DVB DRIVER
> > > > > diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
> > > > > index 697bb053a7d6..0652c044ad76 100644
> > > > > --- a/drivers/platform/x86/ayaneo-ec.c
> > > > > +++ b/drivers/platform/x86/ayaneo-ec.c
> > > > > @@ -8,6 +8,7 @@
> > > > >   */
> > > > >
> > > > >  #include <linux/acpi.h>
> > > > > +#include <linux/bits.h>
> > > > >  #include <linux/dmi.h>
> > > > >  #include <linux/err.h>
> > > > >  #include <linux/hwmon.h>
> > > > > @@ -16,6 +17,7 @@
> > > > >  #include <linux/module.h>
> > > > >  #include <linux/platform_device.h>
> > > > >  #include <linux/power_supply.h>
> > > > > +#include <linux/sysfs.h>
> > > > >  #include <acpi/battery.h>
> > > > >
> > > > >  #define AYANEO_PWM_ENABLE_REG         0x4A
> > > > > @@ -32,9 +34,17 @@
> > > > >  #define AYANEO_CHARGE_VAL_AUTO               0xaa
> > > > >  #define AYANEO_CHARGE_VAL_INHIBIT    0x55
> > > > >
> > > > > +#define AYANEO_POWER_REG     0x2d
> > > > > +#define AYANEO_POWER_OFF     0xfe
> > > > > +#define AYANEO_POWER_ON              0xff
> > > > > +#define AYANEO_MODULE_REG    0x2f
> > > > > +#define AYANEO_MODULE_LEFT   BIT(0)
> > > > > +#define AYANEO_MODULE_RIGHT  BIT(1)
> > > > > +
> > > > >  struct ayaneo_ec_quirk {
> > > > >       bool has_fan_control;
> > > > >       bool has_charge_control;
> > > > > +     bool has_magic_modules;
> > > > >  };
> > > > >
> > > > >  struct ayaneo_ec_platform_data {
> > > > > @@ -46,6 +56,7 @@ struct ayaneo_ec_platform_data {
> > > > >  static const struct ayaneo_ec_quirk quirk_ayaneo3 = {
> > > > >       .has_fan_control = true,
> > > > >       .has_charge_control = true,
> > > > > +     .has_magic_modules = true,
> > > > >  };
> > > > >
> > > > >  static const struct dmi_system_id dmi_table[] = {
> > > > > @@ -266,6 +277,100 @@ static int ayaneo_remove_battery(struct power_supply *battery,
> > > > >       return 0;
> > > > >  }
> > > > >
> > > > > +static ssize_t controller_power_store(struct device *dev,
> > > > > +                                   struct device_attribute *attr,
> > > > > +                                   const char *buf,
> > > > > +                                   size_t count)
> > > > > +{
> > > > > +     bool value;
> > > > > +     int ret;
> > > > > +
> > > > > +     ret = kstrtobool(buf, &value);
> > > > > +     if (ret)
> > > > > +             return ret;
> > > > > +
> > > > > +     ret = ec_write(AYANEO_POWER_REG, value ? AYANEO_POWER_ON : AYANEO_POWER_OFF);
> > > > > +     if (ret)
> > > > > +             return ret;
> > > > > +
> > > > > +     return count;
> > > > > +}
> > > > > +
> > > > > +static ssize_t controller_power_show(struct device *dev,
> > > > > +                                  struct device_attribute *attr,
> > > > > +                                  char *buf)
> > > > > +{
> > > > > +     int ret;
> > > > > +     u8 val;
> > > > > +
> > > > > +     ret = ec_read(AYANEO_POWER_REG, &val);
> > > > > +     if (ret)
> > > > > +             return ret;
> > > > > +
> > > > > +     return sysfs_emit(buf, "%d\n", val == AYANEO_POWER_ON);
> > > > > +}
> > > > > +
> > > > > +static DEVICE_ATTR_RW(controller_power);
> > > > > +
> > > > > +static ssize_t controller_modules_show(struct device *dev,
> > > > > +                                    struct device_attribute *attr, char *buf)
> > > > > +{
> > > > > +     char *out;
> > > > > +     int ret;
> > > > > +     u8 val;
> > > > > +
> > > > > +     ret = ec_read(AYANEO_MODULE_REG, &val);
> > > > > +     if (ret)
> > > > > +             return ret;
> > > > > +
> > > > > +     switch (~val & (AYANEO_MODULE_LEFT | AYANEO_MODULE_RIGHT)) {
> > > >
> > > > This too is constructing mask still here which is ugly.
> > >
> > > I can bring back the bools :-)
> > >
> > > I agree but that's what I came up with to remove them
> >
> > Just Add a define for the mask instead as was requested. There's no need
> > to make this any harder than that.
> 
> Should the mask be:
> 
> (AYANEO_MODULE_LEFT | AYANEO_MODULE_RIGHT)
> 
> or
> 
> GENMASK(2,0)ish

This has a wrong bit index.

> I find the latter a bit more error prone since it redefines. I can
> move forward with the former one later today if there arent any other
> comments

Either way is fine with me, as long as it's not in the switch itself.
I think I lean a bit more to the former one.

-- 
 i.