platform/x86: thinkpad_acpi: Add support for dual fan control

This adds dual fan control for the following models:
P50, P51, P52, P70, P71, P72, P1 gen1, P2 gen2, X1E gen1 and X1E gen2.

Both fans are controlled together as if they were a single fan.

Tested on an X1 Extreme Gen1, an X1 Extreme Gen2, and a P50.

The patch is defensive, it adds only specific supported machines, and falls
back to the old behavior if both fans cannot be controlled.

Background:
I tested the BIOS default behavior on my X1E gen2 and both fans are always
changed together. So rather than adding controls for each fan, this controls
both fans together as the BIOS would do.

This was inspired by a discussion on dual fan support for the thinkfan tool
(see link below). All BIOS IDs are taken from there. The X1E gen2 ID is
verified on my machine.

Thanks to GitHub users voidworker and civic9 for the earlier patches and
BIOS IDs, and to users peter-stoll and sassman for testing the patch on
their machines.

BugLink: https://github.com/vmatare/thinkfan/issues/58Signed-off-by: Lars Hofhansl <larsh@apache.org>
[andy: massaged commit message to capitalize ID and convert to BugLink]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/thinkpad_acpi.c

@@ -318,6 +318,7 @@ static struct {
 	u32 uwb:1;
 	u32 fan_ctrl_status_undef:1;
 	u32 second_fan:1;
+	u32 second_fan_ctl:1;
 	u32 beep_needs_two_args:1;
 	u32 mixer_no_level_control:1;
 	u32 battery_force_primary:1;
@@ -8324,11 +8325,19 @@ static int fan_set_level(int level)
 
 	switch (fan_control_access_mode) {
 	case TPACPI_FAN_WR_ACPI_SFAN:
-		if (level >= 0 && level <= 7) {
+		if ((level < 0) || (level > 7))
+			return -EINVAL;
+
+		if (tp_features.second_fan_ctl) {
+			if (!fan_select_fan2() ||
+			    !acpi_evalf(sfan_handle, NULL, NULL, "vd", level)) {
+				pr_warn("Couldn't set 2nd fan level, disabling support\n");
+				tp_features.second_fan_ctl = 0;
+			}
+			fan_select_fan1();
+		}
 		if (!acpi_evalf(sfan_handle, NULL, NULL, "vd", level))
 			return -EIO;
-		} else
-			return -EINVAL;
 		break;
 
 	case TPACPI_FAN_WR_ACPI_FANS:
@@ -8345,6 +8354,15 @@ static int fan_set_level(int level)
 		else if (level & TP_EC_FAN_AUTO)
 			level |= 4;	/* safety min speed 4 */
 
+		if (tp_features.second_fan_ctl) {
+			if (!fan_select_fan2() ||
+			    !acpi_ec_write(fan_status_offset, level)) {
+				pr_warn("Couldn't set 2nd fan level, disabling support\n");
+				tp_features.second_fan_ctl = 0;
+			}
+			fan_select_fan1();
+
+		}
 		if (!acpi_ec_write(fan_status_offset, level))
 			return -EIO;
 		else
@@ -8763,6 +8781,7 @@ static const struct attribute_group fan_attr_group = {
 
 #define TPACPI_FAN_Q1	0x0001		/* Unitialized HFSP */
 #define TPACPI_FAN_2FAN	0x0002		/* EC 0x31 bit 0 selects fan2 */
+#define TPACPI_FAN_2CTL	0x0004		/* selects fan2 control */
 
 static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_QEC_IBM('1', 'Y', TPACPI_FAN_Q1),
@@ -8771,6 +8790,13 @@ static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_QEC_IBM('7', '0', TPACPI_FAN_Q1),
 	TPACPI_QEC_LNV('7', 'M', TPACPI_FAN_2FAN),
 	TPACPI_Q_LNV('N', '1', TPACPI_FAN_2FAN),
+	TPACPI_Q_LNV3('N', '1', 'D', TPACPI_FAN_2CTL),	/* P70 */
+	TPACPI_Q_LNV3('N', '1', 'E', TPACPI_FAN_2CTL),	/* P50 */
+	TPACPI_Q_LNV3('N', '1', 'T', TPACPI_FAN_2CTL),	/* P71 */
+	TPACPI_Q_LNV3('N', '1', 'U', TPACPI_FAN_2CTL),	/* P51 */
+	TPACPI_Q_LNV3('N', '2', 'C', TPACPI_FAN_2CTL),	/* P52 / P72 */
+	TPACPI_Q_LNV3('N', '2', 'E', TPACPI_FAN_2CTL),	/* P1 / X1 Extreme (1st gen) */
+	TPACPI_Q_LNV3('N', '2', 'O', TPACPI_FAN_2CTL),	/* P1 / X1 Extreme (2nd gen) */
 };
 
 static int __init fan_init(struct ibm_init_struct *iibm)
@@ -8788,6 +8814,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 	fan_watchdog_maxinterval = 0;
 	tp_features.fan_ctrl_status_undef = 0;
 	tp_features.second_fan = 0;
+	tp_features.second_fan_ctl = 0;
 	fan_control_desired_level = 7;
 
 	if (tpacpi_is_ibm()) {
@@ -8812,8 +8839,12 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 				fan_quirk1_setup();
 			if (quirks & TPACPI_FAN_2FAN) {
 				tp_features.second_fan = 1;
-				dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_FAN,
-					"secondary fan support enabled\n");
+				pr_info("secondary fan support enabled\n");
+			}
+			if (quirks & TPACPI_FAN_2CTL) {
+				tp_features.second_fan = 1;
+				tp_features.second_fan_ctl = 1;
+				pr_info("secondary fan control enabled\n");
 			}
 		} else {
 			pr_err("ThinkPad ACPI EC access misbehaving, fan status and control unavailable\n");