[v2,08/17] leds: leds-nuc: add basic support for NUC6 WMI

diff --git a/drivers/leds/leds-nuc.c b/drivers/leds/leds-nuc.c
index e0090626aeec..cd15ed824234 100644
--- a/drivers/leds/leds-nuc.c
+++ b/drivers/leds/leds-nuc.c
@@ -8,12 +8,15 @@ 
  *
  * Inspired on WMI from https://github.com/nomego/intel_nuc_led
  *
- * It follows this spec:
- *	https://www.intel.com/content/dam/support/us/en/documents/intel-nuc/WMI-Spec-Intel-NUC-NUC10ixFNx.pdf
+ * It follows those specs:
+ *   https://www.intel.com/content/www/us/en/support/articles/000023426/intel-nuc/intel-nuc-kits.html
+ *   https://raw.githubusercontent.com/nomego/intel_nuc_led/master/specs/INTEL_WMI_LED_0.64.pdf
+ *   https://www.intel.com/content/dam/support/us/en/documents/intel-nuc/WMI-Spec-Intel-NUC-NUC10ixFNx.pdf
  */
 
 #include <linux/acpi.h>
 #include <linux/bits.h>
+#include <linux/dmi.h>
 #include <linux/kernel.h>
 #include <linux/leds.h>
 #include <linux/module.h>
@@ -34,12 +37,21 @@  enum led_api_rev {
 };
 
 enum led_cmds {
+	/* NUC6-specific cmds */
+	LED_OLD_GET_STATUS              = 0x01,
+	LED_OLD_SET_LED                 = 0x02,
+
+	/* Rev 0.64 and 1.0 cmds */
+
 	LED_QUERY			= 0x03,
 	LED_NEW_GET_STATUS		= 0x04,
 	LED_SET_INDICATOR		= 0x05,
 	LED_SET_VALUE			= 0x06,
 	LED_NOTIFICATION		= 0x07,
 	LED_SWITCH_TYPE			= 0x08,
+
+	/* Rev 1.0 cmds */
+
 	LED_VERSION_CONTROL             = 0x09,
 };
 
@@ -55,6 +67,11 @@  enum led_new_get_subcmd {
 	LED_NEW_GET_CONTROL_ITEM	= 0x01,
 };
 
+enum led_old_get_subcmd {
+	LED_OLD_GET_S0_POWER		= 0x01,
+	LED_OLD_GET_S0_RING		= 0x02,
+};
+
 enum led_function {
 	LED_FUNC_BRIGHTNESS,
 	LED_FUNC_COLOR1,
@@ -146,14 +163,19 @@  static const u8 led_func_rev_1_0_singlecolor[MAX_IND][MAX_LED_FUNC] = {
 #define LED_RGB			BIT(2)
 #define	LED_SINGLE_COLOR	BIT(3)
 
+#define POWER_LED		0
+#define RING_LED		(MAX_LEDS + 1)
+
 static const char * const led_names[] = {
-	"nuc::power",
+	[POWER_LED] = "nuc::power",
 	"nuc::hdd",
 	"nuc::skull",
 	"nuc::eyes",
 	"nuc::front1",
 	"nuc::front2",
 	"nuc::front3",
+
+	[RING_LED] = "nuc::ring",		// NUC6 models
 };
 
 struct nuc_nmi_led {
@@ -276,51 +298,101 @@  static int nuc_nmi_cmd(struct device *dev,
 	return ret;
 }
 
+static int nuc_wmi_query_leds_nuc6(struct device *dev)
+{
+	// FIXME: add a check for the specific models that are known to work
+	struct nuc_wmi *priv = dev_get_drvdata(dev);
+	u8 cmd, input[NUM_INPUT_ARGS] = { 0 };
+	u8 output[NUM_OUTPUT_ARGS];
+	struct nuc_nmi_led *led;
+	int ret;
+
+	cmd = LED_OLD_GET_STATUS;
+	input[0] = LED_OLD_GET_S0_POWER;
+	ret = nuc_nmi_cmd(dev, cmd, input, output);
+	if (ret) {
+		dev_warn(dev, "Get S0 Power: error %d\n", ret);
+		return ret;
+	}
+
+	led = &priv->led[priv->num_leds];
+	led->id = POWER_LED;
+	led->color_type = LED_BLUE_AMBER;
+	led->avail_indicators = LED_IND_POWER_STATE;
+	led->indicator = fls(led->avail_indicators);
+	priv->num_leds++;
+
+	cmd = LED_OLD_GET_STATUS;
+	input[0] = LED_OLD_GET_S0_RING;
+	ret = nuc_nmi_cmd(dev, cmd, input, output);
+	if (ret) {
+		dev_warn(dev, "Get S0 Ring: error %d\n", ret);
+		return ret;
+	}
+	led = &priv->led[priv->num_leds];
+	led->id = RING_LED;
+	led->color_type = LED_BLUE_AMBER;
+	led->avail_indicators = LED_IND_SOFTWARE;
+	led->indicator = fls(led->avail_indicators);
+	priv->num_leds++;
+
+	return 0;
+}
+
 static int nuc_wmi_query_leds(struct device *dev, enum led_api_rev *api_rev)
 {
 	struct nuc_wmi *priv = dev_get_drvdata(dev);
 	u8 input[NUM_INPUT_ARGS] = { 0 };
 	u8 output[NUM_OUTPUT_ARGS];
-	int id, ret, ver = LED_API_UNKNOWN;
+	int id, ret, ver = LED_API_UNKNOWN, nuc_ver = 0;
 	u8 leds;
+	const char *dmi_name;
+
+	dmi_name = dmi_get_system_info(DMI_PRODUCT_NAME);
+	if (!dmi_name || !*dmi_name)
+		dmi_name = dmi_get_system_info(DMI_BOARD_NAME);
+
+	if (strncmp(dmi_name, "NUC", 3))
+		return -ENODEV;
+
+	dmi_name +=3;
+	while (*dmi_name) {
+		if (*dmi_name < '0' || *dmi_name > '9')
+			break;
+		nuc_ver = (*dmi_name - '0') + nuc_ver * 10;
+		dmi_name++;
+	}
+
+	if (nuc_ver < 6)
+		return -ENODEV;
+
+	if (nuc_ver < 8) {
+		*api_rev = LED_API_NUC6;
+		return nuc_wmi_query_leds_nuc6(dev);
+	}
 
-	/*
-	 * List all LED types support in the platform
-	 *
-	 * Should work with both NUC8iXXX and NUC10iXXX
-	 *
-	 * FIXME: Should add a fallback code for it to work with older NUCs,
-	 * as LED_QUERY returns an error on older devices like Skull Canyon.
-	 */
 	input[0] = LED_QUERY_LIST_ALL;
 	ret = nuc_nmi_cmd(dev, LED_QUERY, input, output);
-	if (ret == -ENOENT) {
-		ver = LED_API_NUC6;
-	} else if (ret) {
+	if (ret) {
 		dev_warn(dev, "error %d while listing all LEDs\n", ret);
 		return ret;
-	} else {
-		leds = output[0];
 	}
 
-	if (ver != LED_API_NUC6) {
-		ret = nuc_nmi_cmd(dev, LED_VERSION_CONTROL, input, output);
-		if (ret)
-			return ret;
+	leds = output[0];
 
-		ver = output[0] | output[1] << 16;
-		if (!ver)
-			ver = LED_API_REV_0_64;
-		else if (ver == 0x0126)
-			ver = LED_API_REV_1_0;
-	}
+	ret = nuc_nmi_cmd(dev, LED_VERSION_CONTROL, input, output);
+	if (ret)
+		return ret;
+
+	ver = output[0] | output[1] << 16;
+	if (!ver)
+		*api_rev = LED_API_REV_0_64;
+	else if (ver == 0x0126)
+		*api_rev = LED_API_REV_1_0;
 
-	/* Currently, only API Revision 0.64 is supported */
-	if (ver != LED_API_REV_0_64 && ver != LED_API_REV_1_0)
+	if (*api_rev == LED_API_UNKNOWN)
 		return -ENODEV;
 
-	*api_rev = ver;
-
 	if (!leds) {
 		dev_warn(dev, "No LEDs found\n");
 		return -ENODEV;
@@ -916,10 +988,16 @@  static int nuc_wmi_led_register(struct device *dev, struct nuc_nmi_led *led,
 
 	led->cdev.name = led_names[led->id];
 	led->dev = dev;
+	led->api_rev = api_rev;
+
+	if (led->api_rev == LED_API_NUC6) {
+		// FIXME: add NUC6-specific API bits here
+		return devm_led_classdev_register(dev, &led->cdev);
+	}
+
 	led->cdev.groups = nuc_wmi_led_attribute_groups;
 	led->cdev.brightness_get = nuc_wmi_get_brightness;
 	led->cdev.brightness_set_blocking = nuc_wmi_set_brightness;
-	led->api_rev = api_rev;
 
 	if (led->color_type & LED_SINGLE_COLOR) {
 		if (led->api_rev == LED_API_REV_1_0)