[PATCH] Add IdeaPad quick_charge attribute to sysfs

[Philipp Jungkamp <p.jungkamp@gmx.net>]

More recent IdeaPads allow USB-C quick-charging to be controlled via
ACPI. This seems to be mutually exclusive with the ACPI conservation
mode.

Expose a readable and writable 'quick_charge' sysfs attribute next when
support is indicated in ACPI.
---
I deduced the indicator bits from their names in the DSDT (QCHO and
QCHX). I don't have an IdeaPad except mine on hand and can't check
whether these are indeed the intended uses or their behaviour on other
IdeaPads. I can confirm that a change in the quick_charge toggle is
visible in Lenovo Vantage when dual booting into Windows 11.

Greetings,
Philipp Jungkamp

 drivers/platform/x86/ideapad-laptop.c | 64 ++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index abd0c81d62c4..dea35779264a 100644
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -54,12 +54,16 @@ enum {
 };

 enum {
-	GBMD_CONSERVATION_STATE_BIT = 5,
+	GBMD_QUICK_CHARGE_STATE_BIT   = 2,
+	GBMD_CONSERVATION_STATE_BIT   = 5,
+	GBMD_QUICK_CHARGE_SUPPORT_BIT = 17,
 };

 enum {
 	SBMC_CONSERVATION_ON  = 3,
 	SBMC_CONSERVATION_OFF = 5,
+	SBMC_QUICK_CHARGE_ON  = 7,
+	SBMC_QUICK_CHARGE_OFF = 8,
 };

 enum {
@@ -140,6 +144,7 @@ struct ideapad_private {
 		bool kbd_bl               : 1;
 		bool touchpad_ctrl_via_ec : 1;
 		bool usb_charging         : 1;
+		bool quick_charge         : 1;
 	} features;
 	struct {
 		bool initialized;
@@ -482,6 +487,12 @@ static ssize_t conservation_mode_store(struct device *dev,
 	if (err)
 		return err;

+	if (priv->features.quick_charge && state) {
+		err = exec_sbmc(priv->adev->handle, SBMC_QUICK_CHARGE_OFF);
+		if (err)
+			return err;
+	}
+
 	err = exec_sbmc(priv->adev->handle, state ? SBMC_CONSERVATION_ON : SBMC_CONSERVATION_OFF);
 	if (err)
 		return err;
@@ -491,6 +502,48 @@ static ssize_t conservation_mode_store(struct device *dev,

 static DEVICE_ATTR_RW(conservation_mode);

+static ssize_t quick_charge_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct ideapad_private *priv = dev_get_drvdata(dev);
+	unsigned long result;
+	int err;
+
+	err = eval_gbmd(priv->adev->handle, &result);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", !!test_bit(GBMD_QUICK_CHARGE_STATE_BIT, &result));
+}
+
+static ssize_t quick_charge_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct ideapad_private *priv = dev_get_drvdata(dev);
+	bool state;
+	int err;
+
+	err = kstrtobool(buf, &state);
+	if (err)
+		return err;
+
+	if (priv->features.conservation_mode && state) {
+		err = exec_sbmc(priv->adev->handle, SBMC_CONSERVATION_OFF);
+		if (err)
+			return err;
+	}
+
+	err = exec_sbmc(priv->adev->handle, state ? SBMC_QUICK_CHARGE_ON : SBMC_QUICK_CHARGE_OFF);
+	if (err)
+		return err;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(quick_charge);
+
 static ssize_t fan_mode_show(struct device *dev,
 			     struct device_attribute *attr,
 			     char *buf)
@@ -641,6 +694,7 @@ static DEVICE_ATTR_RW(usb_charging);
 static struct attribute *ideapad_attributes[] = {
 	&dev_attr_camera_power.attr,
 	&dev_attr_conservation_mode.attr,
+	&dev_attr_quick_charge.attr,
 	&dev_attr_fan_mode.attr,
 	&dev_attr_fn_lock.attr,
 	&dev_attr_touchpad.attr,
@@ -660,6 +714,8 @@ static umode_t ideapad_is_visible(struct kobject *kobj,
 		supported = test_bit(CFG_CAP_CAM_BIT, &priv->cfg);
 	else if (attr == &dev_attr_conservation_mode.attr)
 		supported = priv->features.conservation_mode;
+	else if (attr == &dev_attr_quick_charge.attr)
+		supported = priv->features.quick_charge;
 	else if (attr == &dev_attr_fan_mode.attr)
 		supported = priv->features.fan_mode;
 	else if (attr == &dev_attr_fn_lock.attr)
@@ -1546,9 +1602,13 @@ static void ideapad_check_features(struct ideapad_private *priv)
 	if (!read_ec_data(handle, VPCCMD_R_FAN, &val))
 		priv->features.fan_mode = true;

-	if (acpi_has_method(handle, "GBMD") && acpi_has_method(handle, "SBMC"))
+	if (acpi_has_method(handle, "GBMD") && acpi_has_method(handle, "SBMC")) {
 		priv->features.conservation_mode = true;

+		if (!eval_gbmd(handle,&val) && test_bit(GBMD_QUICK_CHARGE_SUPPORT_BIT, &val))
+			priv->features.quick_charge = true;
+	}
+
 	if (acpi_has_method(handle, "DYTC"))
 		priv->features.dytc = true;

--
2.37.3