[PATCH v2 2/4] platform/x86/uniwill: Implement USB-C power priority setting

[Werner Sembach <wse@tuxedocomputers.com>]

On some devices Uniwill offers the option to set the USB-C port to
prioritise charging or performance. This patch exposes this setting to the
userspace via sysfs for all TUXEDO devices supporting it.

Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
---
 drivers/platform/x86/uniwill/uniwill-acpi.c | 103 ++++++++++++++++++--
 1 file changed, 97 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/uniwill/uniwill-acpi.c b/drivers/platform/x86/uniwill/uniwill-acpi.c
index 7ab82cf16f388..a34b1eed74eb2 100644
--- a/drivers/platform/x86/uniwill/uniwill-acpi.c
+++ b/drivers/platform/x86/uniwill/uniwill-acpi.c
@@ -266,8 +266,8 @@
 #define BATTERY_CHARGE_FULL_OVER_24H	BIT(3)
 #define BATTERY_ERM_STATUS_REACHED	BIT(4)
 
-#define EC_ADDR_CHARGE_PRIO		0x07CC
-#define CHARGING_PERFORMANCE		BIT(7)
+#define EC_ADDR_USB_C_POWER_PRIORITY	0x07CC
+#define USB_C_POWER_PRIORITY		BIT(7)
 
 /* Same bits as EC_ADDR_LIGHTBAR_AC_CTRL except LIGHTBAR_S3_OFF */
 #define EC_ADDR_LIGHTBAR_BAT_CTRL	0x07E2
@@ -324,6 +324,7 @@
 #define UNIWILL_FEATURE_PRIMARY_FAN		BIT(7)
 #define UNIWILL_FEATURE_SECONDARY_FAN		BIT(8)
 #define UNIWILL_FEATURE_NVIDIA_CTGP_CONTROL	BIT(9)
+#define UNIWILL_FEATURE_USB_C_POWER_PRIORITY	BIT(10)
 
 struct uniwill_data {
 	struct device *dev;
@@ -343,6 +344,8 @@ struct uniwill_data {
 	struct mutex input_lock;	/* Protects input sequence during notify */
 	struct input_dev *input_device;
 	struct notifier_block nb;
+	struct mutex usb_c_power_priority_lock; /* Protects dependent bit write and state safe */
+	unsigned int last_usb_c_power_priority;
 };
 
 struct uniwill_battery_entry {
@@ -527,6 +530,7 @@ static bool uniwill_writeable_reg(struct device *dev, unsigned int reg)
 	case EC_ADDR_CTGP_DB_CTGP_OFFSET:
 	case EC_ADDR_CTGP_DB_TPP_OFFSET:
 	case EC_ADDR_CTGP_DB_DB_OFFSET:
+	case EC_ADDR_USB_C_POWER_PRIORITY:
 		return true;
 	default:
 		return false;
@@ -565,6 +569,7 @@ static bool uniwill_readable_reg(struct device *dev, unsigned int reg)
 	case EC_ADDR_CTGP_DB_CTGP_OFFSET:
 	case EC_ADDR_CTGP_DB_TPP_OFFSET:
 	case EC_ADDR_CTGP_DB_DB_OFFSET:
+	case EC_ADDR_USB_C_POWER_PRIORITY:
 		return true;
 	default:
 		return false;
@@ -587,6 +592,7 @@ static bool uniwill_volatile_reg(struct device *dev, unsigned int reg)
 	case EC_ADDR_TRIGGER:
 	case EC_ADDR_SWITCH_STATUS:
 	case EC_ADDR_CHARGE_CTRL:
+	case EC_ADDR_USB_C_POWER_PRIORITY:
 		return true;
 	default:
 		return false;
@@ -883,6 +889,78 @@ static int uniwill_nvidia_ctgp_init(struct uniwill_data *data)
 	return 0;
 }
 
+enum usb_c_power_priority_options {
+	USB_C_POWER_PRIORITY_OPTIONS_CHARGING = 0,
+	USB_C_POWER_PRIORITY_OPTIONS_PERFORMANCE,
+};
+
+static const char * const USB_C_POWER_PRIORITY_OPTIONS_TEXT[] = {
+	[USB_C_POWER_PRIORITY_OPTIONS_CHARGING]		= "charging",
+	[USB_C_POWER_PRIORITY_OPTIONS_PERFORMANCE]	= "performance",
+};
+
+static const u8 USB_C_POWER_PRIORITY_OPTIONS_VALUE[] = {
+	[USB_C_POWER_PRIORITY_OPTIONS_CHARGING]		= 0,
+	[USB_C_POWER_PRIORITY_OPTIONS_PERFORMANCE]	= USB_C_POWER_PRIORITY,
+};
+
+static ssize_t usb_c_power_priority_store(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t count)
+{
+	struct uniwill_data *data = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	ret = sysfs_match_string(USB_C_POWER_PRIORITY_OPTIONS_TEXT, buf);
+	if (ret < 0)
+		return ret;
+
+	value = USB_C_POWER_PRIORITY_OPTIONS_VALUE[ret];
+
+	guard(mutex)(&data->usb_c_power_priority_lock);
+
+	ret = regmap_update_bits(data->regmap, EC_ADDR_USB_C_POWER_PRIORITY,
+				 USB_C_POWER_PRIORITY, value);
+	if (ret < 0)
+		return ret;
+
+	data->last_usb_c_power_priority = value;
+
+	return count;
+}
+
+static ssize_t usb_c_power_priority_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct uniwill_data *data = dev_get_drvdata(dev);
+	unsigned int value;
+	ssize_t count = 0;
+	int ret;
+
+	ret = regmap_read(data->regmap, EC_ADDR_USB_C_POWER_PRIORITY, &value);
+	if (ret < 0)
+		return ret;
+
+	value &= USB_C_POWER_PRIORITY;
+
+	for (int i = 0; i < ARRAY_SIZE(USB_C_POWER_PRIORITY_OPTIONS_VALUE); ++i) {
+		if (USB_C_POWER_PRIORITY_OPTIONS_VALUE[i] == value)
+			count += sysfs_emit_at(buf, count, "[%s] ",
+					       USB_C_POWER_PRIORITY_OPTIONS_TEXT[i]);
+		else
+			count += sysfs_emit_at(buf, count, "%s ",
+					       USB_C_POWER_PRIORITY_OPTIONS_TEXT[i]);
+	}
+	if (count)
+		buf[count - 1] = '\n';
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(usb_c_power_priority);
+
 static struct attribute *uniwill_attrs[] = {
 	/* Keyboard-related */
 	&dev_attr_fn_lock.attr,
@@ -893,6 +971,7 @@ static struct attribute *uniwill_attrs[] = {
 	&dev_attr_breathing_in_suspend.attr,
 	/* Power-management-related */
 	&dev_attr_ctgp_offset.attr,
+	&dev_attr_usb_c_power_priority.attr,
 	NULL
 };
 
@@ -927,6 +1006,11 @@ static umode_t uniwill_attr_is_visible(struct kobject *kobj, struct attribute *a
 			return attr->mode;
 	}
 
+	if (attr == &dev_attr_usb_c_power_priority.attr) {
+		if (uniwill_device_supports(data, UNIWILL_FEATURE_USB_C_POWER_PRIORITY))
+			return attr->mode;
+	}
+
 	return 0;
 }
 
@@ -1417,11 +1501,13 @@ static int uniwill_notifier_call(struct notifier_block *nb, unsigned long action
 
 		return NOTIFY_OK;
 	case UNIWILL_OSD_DC_ADAPTER_CHANGED:
-		/* noop for the time being, will change once charging priority
-		 * gets implemented.
-		 */
+		if (!uniwill_device_supports(data, UNIWILL_FEATURE_USB_C_POWER_PRIORITY))
+			return NOTIFY_DONE;
 
-		return NOTIFY_OK;
+		return notifier_from_errno(regmap_update_bits(data->regmap,
+							      EC_ADDR_OEM_4,
+							      USB_C_POWER_PRIORITY,
+							      data->last_usb_c_power_priority));
 	case UNIWILL_OSD_FN_LOCK:
 		if (!uniwill_device_supports(data, UNIWILL_FEATURE_FN_LOCK))
 			return NOTIFY_DONE;
@@ -1515,10 +1601,15 @@ static int uniwill_probe(struct platform_device *pdev)
 		return PTR_ERR(regmap);
 
 	data->regmap = regmap;
+
 	ret = devm_mutex_init(&pdev->dev, &data->super_key_lock);
 	if (ret < 0)
 		return ret;
 
+	ret = devm_mutex_init(&pdev->dev, &data->usb_c_power_priority_lock);
+	if (ret < 0)
+		return ret;
+
 	ret = uniwill_ec_init(data);
 	if (ret < 0)
 		return ret;
-- 
2.43.0