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Message-Id: <f0454d78-0fe9-431d-a0c9-6f7db7809039@app.fastmail.com>
Date: Wed, 22 Oct 2025 20:43:20 +0200
From: "Mark Pearson" <mpearson-lenovo@...ebb.ca>
To: "Rong Zhang" <i@...g.moe>, "Ike Panhc" <ikepanhc@...il.com>,
"Derek J . Clark" <derekjohn.clark@...il.com>,
"Hans de Goede" <hansg@...nel.org>,
Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:
"platform-driver-x86@...r.kernel.org" <platform-driver-x86@...r.kernel.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] platform/x86: ideapad-laptop: Add charge_types:Fast (Rapid
Charge)
Hi Rong
On Mon, Oct 20, 2025, at 9:24 PM, Rong Zhang wrote:
> The GBMD/SBMC interface supports Rapid Charge mode (charge_types: Fast)
> in addition to Conservation Mode (charge_types: Long_Life).
>
> Expose these two modes while carefully maintaining their mutually
> exclusive state, which aligns with the behavior of manufacturer
> utilities on Windows.
>
> Signed-off-by: Rong Zhang <i@...g.moe>
> ---
> drivers/platform/x86/lenovo/ideapad-laptop.c | 61 ++++++++++++++++++--
> 1 file changed, 56 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/x86/lenovo/ideapad-laptop.c
> b/drivers/platform/x86/lenovo/ideapad-laptop.c
> index 9f956f51ec8db..d2bfaa532020a 100644
> --- a/drivers/platform/x86/lenovo/ideapad-laptop.c
> +++ b/drivers/platform/x86/lenovo/ideapad-laptop.c
> @@ -62,13 +62,26 @@ enum {
> CFG_OSD_CAM_BIT = 31,
> };
>
> +/*
> + * There are two charge modes supported by the GBMD/SBMC interface:
> + * - "Rapid Charge": increase power to speed up charging
> + * - "Conservation Mode": stop charging at 60-80% (depends on model)
> + *
> + * The interface doesn't prohibit enabling both modes at the same time.
> + * However, doing so is essentially meaningless, and the manufacturer utilities
> + * on Windows always make them mutually exclusive.
> + */
> +
> enum {
> + GBMD_RAPID_CHARGE_STATE_BIT = 2,
> GBMD_CONSERVATION_STATE_BIT = 5,
> };
>
> enum {
> SBMC_CONSERVATION_ON = 3,
> SBMC_CONSERVATION_OFF = 5,
> + SBMC_RAPID_CHARGE_ON = 7,
> + SBMC_RAPID_CHARGE_OFF = 8,
> };
>
> enum {
> @@ -632,6 +645,10 @@ static ssize_t conservation_mode_show(struct device *dev,
> return err;
> }
>
> + /*
> + * For backward compatibility, ignore Rapid Charge while reporting the
> + * state of Conservation Mode.
> + */
> return sysfs_emit(buf, "%d\n",
> !!test_bit(GBMD_CONSERVATION_STATE_BIT, &result));
> }
>
> @@ -651,6 +668,16 @@ static ssize_t conservation_mode_store(struct device *dev,
>
> guard(mutex)(&priv->gbmd_sbmc_mutex);
>
> + /*
> + * Prevent mutually exclusive modes from being set at the same time,
> + * but do not disable Rapid Charge while disabling Conservation Mode.
> + */
> + if (state) {
> + err = exec_sbmc(priv->adev->handle, SBMC_RAPID_CHARGE_OFF);
> + if (err)
> + return err;
> + }
> +
> err = exec_sbmc(priv->adev->handle, state ? SBMC_CONSERVATION_ON :
> SBMC_CONSERVATION_OFF);
> if (err)
> return err;
> @@ -2015,14 +2042,21 @@ static int ideapad_psy_ext_set_prop(struct
> power_supply *psy,
> const union power_supply_propval *val)
> {
> struct ideapad_private *priv = ext_data;
> - unsigned long op;
> + unsigned long op1, op2;
> + int err;
>
> switch (val->intval) {
> + case POWER_SUPPLY_CHARGE_TYPE_FAST:
> + op1 = SBMC_CONSERVATION_OFF;
> + op2 = SBMC_RAPID_CHARGE_ON;
> + break;
> case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
> - op = SBMC_CONSERVATION_ON;
> + op1 = SBMC_RAPID_CHARGE_OFF;
> + op2 = SBMC_CONSERVATION_ON;
> break;
> case POWER_SUPPLY_CHARGE_TYPE_STANDARD:
> - op = SBMC_CONSERVATION_OFF;
> + op1 = SBMC_RAPID_CHARGE_OFF;
> + op2 = SBMC_CONSERVATION_OFF;
> break;
> default:
> return -EINVAL;
> @@ -2030,7 +2064,11 @@ static int ideapad_psy_ext_set_prop(struct
> power_supply *psy,
>
> guard(mutex)(&priv->gbmd_sbmc_mutex);
>
> - return exec_sbmc(priv->adev->handle, op);
> + err = exec_sbmc(priv->adev->handle, op1);
> + if (err)
> + return err;
> +
> + return exec_sbmc(priv->adev->handle, op2);
> }
>
> static int ideapad_psy_ext_get_prop(struct power_supply *psy,
> @@ -2042,6 +2080,7 @@ static int ideapad_psy_ext_get_prop(struct
> power_supply *psy,
> struct ideapad_private *priv = ext_data;
> unsigned long result;
> int err;
> + bool is_rapid_charge, is_conservation;
>
> scoped_guard(mutex, &priv->gbmd_sbmc_mutex) {
> err = eval_gbmd(priv->adev->handle, &result);
> @@ -2049,7 +2088,18 @@ static int ideapad_psy_ext_get_prop(struct
> power_supply *psy,
> return err;
> }
>
> - if (test_bit(GBMD_CONSERVATION_STATE_BIT, &result))
> + is_rapid_charge = test_bit(GBMD_RAPID_CHARGE_STATE_BIT, &result);
> + is_conservation = test_bit(GBMD_CONSERVATION_STATE_BIT, &result);
> +
> + if (unlikely(is_rapid_charge && is_conservation)) {
> + dev_err(&priv->platform_device->dev,
> + "unexpected charge_types: both [Fast] and [Long_Life] are
> enabled\n");
> + return -EINVAL;
> + }
> +
> + if (is_rapid_charge)
> + val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
> + else if (is_conservation)
> val->intval = POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
> else
> val->intval = POWER_SUPPLY_CHARGE_TYPE_STANDARD;
> @@ -2074,6 +2124,7 @@ static const struct power_supply_ext
> ideapad_battery_ext = {
> .properties = ideapad_power_supply_props,
> .num_properties = ARRAY_SIZE(ideapad_power_supply_props),
> .charge_types = (BIT(POWER_SUPPLY_CHARGE_TYPE_STANDARD) |
> + BIT(POWER_SUPPLY_CHARGE_TYPE_FAST) |
> BIT(POWER_SUPPLY_CHARGE_TYPE_LONGLIFE)),
> .get_property = ideapad_psy_ext_get_prop,
> .set_property = ideapad_psy_ext_set_prop,
> --
> 2.51.0
I can't comment on the functionality as I don't have hooks into the Ideapad team to confirm - but the implementation looks good to me.
Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
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