[PATCH v2] hwmon: yogafan: add Lenovo Yoga Pro 9 16IMH9

The Lenovo Yoga Pro 9 16IMH9 (83DN) exposes its fan tachometers at
ACPI paths different from the generic Yoga configuration. Add a
model-specific two-fan configuration for the PC00.LPCB.EC0 namespace
and document the corrected mapping.

Tested on a Lenovo Yoga Pro 9 16IMH9 (83DN) with BIOS NKCN35WW: the
patched module registers fan1_input and fan2_input, both reporting 1800
RPM at idle.

---

Changes from v1:
- Wrap the new comment in kernel block-comment style.
- Wrap the commit message to 75 columns.

Signed-off-by: rahlquist <[email protected]>
---
 Documentation/hwmon/yogafan.rst |  3 ++-
 drivers/hwmon/yogafan.c         | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Documentation/hwmon/yogafan.rst b/Documentation/hwmon/yogafan.rst
index 6876194..cd7206b 100644
--- a/Documentation/hwmon/yogafan.rst
+++ b/Documentation/hwmon/yogafan.rst
@@ -89,7 +89,8 @@ immediately to ensure the user knows the fan has stopped.
  ----------------------------------------------------------------------------------------------------
  82N7           | Yoga 14cACN      | 0x06      | \_SB.PCI0.LPC0.EC0.FANS        |  8-bit | 100
  80V2 / 81C3    | Yoga 710/720     | 0x06      | \_SB.PCI0.LPC0.EC0.FAN0        |  8-bit | 100
- 83E2 / 83DN    | Yoga Pro 7/9     | 0xFE      | \_SB.PCI0.LPC0.EC0.FANS        |  8-bit | 100
+ 83E2           | Yoga Pro 7       | 0xFE      | \_SB.PCI0.LPC0.EC0.FANS        |  8-bit | 100
+ 83DN           | Yoga Pro 9 16IMH9 | 0x06/0xFE | \_SB.PC00.LPCB.EC0.FANS/FA2S  |  8-bit | 100
  82A2 / 82A3    | Yoga Slim 7      | 0x06      | \_SB.PCI0.LPC0.EC0.FANS        |  8-bit | 100
  81YM / 82FG    | IdeaPad 5        | 0x06      | \_SB.PCI0.LPC0.EC0.FAN0        |  8-bit | 100
  82JW / 82JU    | Legion 5 (AMD)   | 0xFE/0xFF | \_SB.PCI0.LPC0.EC0.FANS (Fan1) | 16-bit | 1
diff --git a/drivers/hwmon/yogafan.c b/drivers/hwmon/yogafan.c
index 605cc92..6cfbad3 100644
--- a/drivers/hwmon/yogafan.c
+++ b/drivers/hwmon/yogafan.c
@@ -71,6 +71,17 @@ static const struct yogafan_config legion_16bit_dual_cfg = {
 	.paths = { "\\_SB.PCI0.LPC0.EC0.FANS", "\\_SB.PCI0.LPC0.EC0.FA2S" }
 };
 
+/*
+ * Lenovo Yoga Pro 9 16IMH9 (83DN) uses the PC00 namespace and has two
+ * 8-bit fan tachometer fields.
+ */
+static const struct yogafan_config yoga_pro_83dn_cfg = {
+	.multiplier = 100,
+	.fan_count = 2,
+	.paths = { "\\_SB.PC00.LPCB.EC0.FANS",
+		   "\\_SB.PC00.LPCB.EC0.FA2S" }
+};
+
 static void apply_rllag_filter(struct yoga_fan_data *data, int idx, long raw_rpm)
 {
 	ktime_t now = ktime_get_boottime();
@@ -170,6 +181,14 @@ static const struct hwmon_chip_info yoga_fan_chip_info = {
 };
 
 static const struct dmi_system_id yogafan_quirks[] = {
+	{
+		.ident = "Lenovo Yoga Pro 9 16IMH9 (83DN)",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "83DN"),
+		},
+		.driver_data = (void *)&yoga_pro_83dn_cfg,
+	},
 	{
 		.ident = "Lenovo Yoga",
 		.matches = {
-- 
2.55.0