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2023-12-06 08f87f769b595151be1afeff53e144f543faa614 
 kernel/drivers/hwmon/dell-smm-hwmon.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
34  *
....@@ -6,17 +7,7 @@
67  * Hwmon integration:
78  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
89  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
9
- * Copyright (C) 2014, 2015  Pali Rohár <pali.rohar@gmail.com>
10
- *
11
- * This program is free software; you can redistribute it and/or modify it
12
- * under the terms of the GNU General Public License as published by the
13
- * Free Software Foundation; either version 2, or (at your option) any
14
- * later version.
15
- *
16
- * This program is distributed in the hope that it will be useful, but
17
- * WITHOUT ANY WARRANTY; without even the implied warranty of
18
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19
- * General Public License for more details.
10
+ * Copyright (C) 2014, 2015  Pali Rohár <pali@kernel.org>
2011  */
2112 
2213 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
....@@ -77,17 +68,25 @@
7768 static uint i8k_fan_max = I8K_FAN_HIGH;
7869 static bool disallow_fan_type_call;
7970 static bool disallow_fan_support;
71
+static unsigned int manual_fan;
72
+static unsigned int auto_fan;
8073 
8174 #define I8K_HWMON_HAVE_TEMP1	(1 << 0)
8275 #define I8K_HWMON_HAVE_TEMP2	(1 << 1)
8376 #define I8K_HWMON_HAVE_TEMP3	(1 << 2)
8477 #define I8K_HWMON_HAVE_TEMP4	(1 << 3)
85
-#define I8K_HWMON_HAVE_FAN1	(1 << 4)
86
-#define I8K_HWMON_HAVE_FAN2	(1 << 5)
87
-#define I8K_HWMON_HAVE_FAN3	(1 << 6)
78
+#define I8K_HWMON_HAVE_TEMP5	(1 << 4)
79
+#define I8K_HWMON_HAVE_TEMP6	(1 << 5)
80
+#define I8K_HWMON_HAVE_TEMP7	(1 << 6)
81
+#define I8K_HWMON_HAVE_TEMP8	(1 << 7)
82
+#define I8K_HWMON_HAVE_TEMP9	(1 << 8)
83
+#define I8K_HWMON_HAVE_TEMP10	(1 << 9)
84
+#define I8K_HWMON_HAVE_FAN1	(1 << 10)
85
+#define I8K_HWMON_HAVE_FAN2	(1 << 11)
86
+#define I8K_HWMON_HAVE_FAN3	(1 << 12)
8887 
8988 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
90
-MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
89
+MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
9190 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
9291 MODULE_LICENSE("GPL");
9392 MODULE_ALIAS("i8k");
....@@ -301,6 +300,20 @@
301300 
302301 	regs.ebx = (fan & 0xff) | (speed << 8);
303302 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
303
+}
304
+
305
+/*
306
+ * Enable or disable automatic BIOS fan control support
307
+ */
308
+static int i8k_enable_fan_auto_mode(bool enable)
309
+{
310
+	struct smm_regs regs = { };
311
+
312
+	if (disallow_fan_support)
313
+		return -EINVAL;
314
+
315
+	regs.eax = enable ? auto_fan : manual_fan;
316
+	return i8k_smm(&regs);
304317 }
305318 
306319 /*
....@@ -586,13 +599,12 @@
586599 	return single_open(file, i8k_proc_show, NULL);
587600 }
588601 
589
-static const struct file_operations i8k_fops = {
590
-	.owner		= THIS_MODULE,
591
-	.open		= i8k_open_fs,
592
-	.read		= seq_read,
593
-	.llseek		= seq_lseek,
594
-	.release	= single_release,
595
-	.unlocked_ioctl	= i8k_ioctl,
602
+static const struct proc_ops i8k_proc_ops = {
603
+	.proc_open	= i8k_open_fs,
604
+	.proc_read	= seq_read,
605
+	.proc_lseek	= seq_lseek,
606
+	.proc_release	= single_release,
607
+	.proc_ioctl	= i8k_ioctl,
596608 };
597609 
598610 static struct proc_dir_entry *entry;
....@@ -600,7 +612,7 @@
600612 static void __init i8k_init_procfs(void)
601613 {
602614 	/* Register the proc entry */
603
-	entry = proc_create("i8k", 0, NULL, &i8k_fops);
615
+	entry = proc_create("i8k", 0, NULL, &i8k_proc_ops);
604616 }
605617 
606618 static void __exit i8k_exit_procfs(void)
....@@ -625,7 +637,7 @@
625637  * Hwmon interface
626638  */
627639 
628
-static ssize_t i8k_hwmon_show_temp_label(struct device *dev,
640
+static ssize_t i8k_hwmon_temp_label_show(struct device *dev,
629641 					 struct device_attribute *devattr,
630642 					 char *buf)
631643 {
....@@ -648,7 +660,7 @@
648660 	return sprintf(buf, "%s\n", labels[type]);
649661 }
650662 
651
-static ssize_t i8k_hwmon_show_temp(struct device *dev,
663
+static ssize_t i8k_hwmon_temp_show(struct device *dev,
652664 				   struct device_attribute *devattr,
653665 				   char *buf)
654666 {
....@@ -661,7 +673,7 @@
661673 	return sprintf(buf, "%d\n", temp * 1000);
662674 }
663675 
664
-static ssize_t i8k_hwmon_show_fan_label(struct device *dev,
676
+static ssize_t i8k_hwmon_fan_label_show(struct device *dev,
665677 					struct device_attribute *devattr,
666678 					char *buf)
667679 {
....@@ -692,9 +704,8 @@
692704 	return sprintf(buf, "%s%s\n", (dock ? "Docking " : ""), labels[type]);
693705 }
694706 
695
-static ssize_t i8k_hwmon_show_fan(struct device *dev,
696
-				  struct device_attribute *devattr,
697
-				  char *buf)
707
+static ssize_t i8k_hwmon_fan_show(struct device *dev,
708
+				  struct device_attribute *devattr, char *buf)
698709 {
699710 	int index = to_sensor_dev_attr(devattr)->index;
700711 	int fan_speed;
....@@ -705,9 +716,8 @@
705716 	return sprintf(buf, "%d\n", fan_speed);
706717 }
707718 
708
-static ssize_t i8k_hwmon_show_pwm(struct device *dev,
709
-				  struct device_attribute *devattr,
710
-				  char *buf)
719
+static ssize_t i8k_hwmon_pwm_show(struct device *dev,
720
+				  struct device_attribute *devattr, char *buf)
711721 {
712722 	int index = to_sensor_dev_attr(devattr)->index;
713723 	int status;
....@@ -718,9 +728,9 @@
718728 	return sprintf(buf, "%d\n", clamp_val(status * i8k_pwm_mult, 0, 255));
719729 }
720730 
721
-static ssize_t i8k_hwmon_set_pwm(struct device *dev,
722
-				 struct device_attribute *attr,
723
-				 const char *buf, size_t count)
731
+static ssize_t i8k_hwmon_pwm_store(struct device *dev,
732
+				   struct device_attribute *attr,
733
+				   const char *buf, size_t count)
724734 {
725735 	int index = to_sensor_dev_attr(attr)->index;
726736 	unsigned long val;
....@@ -738,35 +748,65 @@
738748 	return err < 0 ? -EIO : count;
739749 }
740750 
741
-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 0);
742
-static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
743
-			  0);
744
-static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 1);
745
-static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
746
-			  1);
747
-static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
748
-static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
749
-			  2);
750
-static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
751
-static SENSOR_DEVICE_ATTR(temp4_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
752
-			  3);
753
-static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL, 0);
754
-static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
755
-			  0);
756
-static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
757
-			  i8k_hwmon_set_pwm, 0);
758
-static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
759
-			  1);
760
-static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
761
-			  1);
762
-static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
763
-			  i8k_hwmon_set_pwm, 1);
764
-static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
765
-			  2);
766
-static SENSOR_DEVICE_ATTR(fan3_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
767
-			  2);
768
-static SENSOR_DEVICE_ATTR(pwm3, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
769
-			  i8k_hwmon_set_pwm, 2);
751
+static ssize_t i8k_hwmon_pwm_enable_store(struct device *dev,
752
+					  struct device_attribute *attr,
753
+					  const char *buf, size_t count)
754
+{
755
+	int err;
756
+	bool enable;
757
+	unsigned long val;
758
+
759
+	if (!auto_fan)
760
+		return -ENODEV;
761
+
762
+	err = kstrtoul(buf, 10, &val);
763
+	if (err)
764
+		return err;
765
+
766
+	if (val == 1)
767
+		enable = false;
768
+	else if (val == 2)
769
+		enable = true;
770
+	else
771
+		return -EINVAL;
772
+
773
+	mutex_lock(&i8k_mutex);
774
+	err = i8k_enable_fan_auto_mode(enable);
775
+	mutex_unlock(&i8k_mutex);
776
+
777
+	return err ? err : count;
778
+}
779
+
780
+static SENSOR_DEVICE_ATTR_RO(temp1_input, i8k_hwmon_temp, 0);
781
+static SENSOR_DEVICE_ATTR_RO(temp1_label, i8k_hwmon_temp_label, 0);
782
+static SENSOR_DEVICE_ATTR_RO(temp2_input, i8k_hwmon_temp, 1);
783
+static SENSOR_DEVICE_ATTR_RO(temp2_label, i8k_hwmon_temp_label, 1);
784
+static SENSOR_DEVICE_ATTR_RO(temp3_input, i8k_hwmon_temp, 2);
785
+static SENSOR_DEVICE_ATTR_RO(temp3_label, i8k_hwmon_temp_label, 2);
786
+static SENSOR_DEVICE_ATTR_RO(temp4_input, i8k_hwmon_temp, 3);
787
+static SENSOR_DEVICE_ATTR_RO(temp4_label, i8k_hwmon_temp_label, 3);
788
+static SENSOR_DEVICE_ATTR_RO(temp5_input, i8k_hwmon_temp, 4);
789
+static SENSOR_DEVICE_ATTR_RO(temp5_label, i8k_hwmon_temp_label, 4);
790
+static SENSOR_DEVICE_ATTR_RO(temp6_input, i8k_hwmon_temp, 5);
791
+static SENSOR_DEVICE_ATTR_RO(temp6_label, i8k_hwmon_temp_label, 5);
792
+static SENSOR_DEVICE_ATTR_RO(temp7_input, i8k_hwmon_temp, 6);
793
+static SENSOR_DEVICE_ATTR_RO(temp7_label, i8k_hwmon_temp_label, 6);
794
+static SENSOR_DEVICE_ATTR_RO(temp8_input, i8k_hwmon_temp, 7);
795
+static SENSOR_DEVICE_ATTR_RO(temp8_label, i8k_hwmon_temp_label, 7);
796
+static SENSOR_DEVICE_ATTR_RO(temp9_input, i8k_hwmon_temp, 8);
797
+static SENSOR_DEVICE_ATTR_RO(temp9_label, i8k_hwmon_temp_label, 8);
798
+static SENSOR_DEVICE_ATTR_RO(temp10_input, i8k_hwmon_temp, 9);
799
+static SENSOR_DEVICE_ATTR_RO(temp10_label, i8k_hwmon_temp_label, 9);
800
+static SENSOR_DEVICE_ATTR_RO(fan1_input, i8k_hwmon_fan, 0);
801
+static SENSOR_DEVICE_ATTR_RO(fan1_label, i8k_hwmon_fan_label, 0);
802
+static SENSOR_DEVICE_ATTR_RW(pwm1, i8k_hwmon_pwm, 0);
803
+static SENSOR_DEVICE_ATTR_WO(pwm1_enable, i8k_hwmon_pwm_enable, 0);
804
+static SENSOR_DEVICE_ATTR_RO(fan2_input, i8k_hwmon_fan, 1);
805
+static SENSOR_DEVICE_ATTR_RO(fan2_label, i8k_hwmon_fan_label, 1);
806
+static SENSOR_DEVICE_ATTR_RW(pwm2, i8k_hwmon_pwm, 1);
807
+static SENSOR_DEVICE_ATTR_RO(fan3_input, i8k_hwmon_fan, 2);
808
+static SENSOR_DEVICE_ATTR_RO(fan3_label, i8k_hwmon_fan_label, 2);
809
+static SENSOR_DEVICE_ATTR_RW(pwm3, i8k_hwmon_pwm, 2);
770810 
771811 static struct attribute *i8k_attrs[] = {
772812 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
....@@ -777,25 +817,38 @@
777817 	&sensor_dev_attr_temp3_label.dev_attr.attr,	/* 5 */
778818 	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 6 */
779819 	&sensor_dev_attr_temp4_label.dev_attr.attr,	/* 7 */
780
-	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 8 */
781
-	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 9 */
782
-	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 10 */
783
-	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 11 */
784
-	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 12 */
785
-	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 13 */
786
-	&sensor_dev_attr_fan3_input.dev_attr.attr,	/* 14 */
787
-	&sensor_dev_attr_fan3_label.dev_attr.attr,	/* 15 */
788
-	&sensor_dev_attr_pwm3.dev_attr.attr,		/* 16 */
820
+	&sensor_dev_attr_temp5_input.dev_attr.attr,	/* 8 */
821
+	&sensor_dev_attr_temp5_label.dev_attr.attr,	/* 9 */
822
+	&sensor_dev_attr_temp6_input.dev_attr.attr,	/* 10 */
823
+	&sensor_dev_attr_temp6_label.dev_attr.attr,	/* 11 */
824
+	&sensor_dev_attr_temp7_input.dev_attr.attr,	/* 12 */
825
+	&sensor_dev_attr_temp7_label.dev_attr.attr,	/* 13 */
826
+	&sensor_dev_attr_temp8_input.dev_attr.attr,	/* 14 */
827
+	&sensor_dev_attr_temp8_label.dev_attr.attr,	/* 15 */
828
+	&sensor_dev_attr_temp9_input.dev_attr.attr,	/* 16 */
829
+	&sensor_dev_attr_temp9_label.dev_attr.attr,	/* 17 */
830
+	&sensor_dev_attr_temp10_input.dev_attr.attr,	/* 18 */
831
+	&sensor_dev_attr_temp10_label.dev_attr.attr,	/* 19 */
832
+	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 20 */
833
+	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 21 */
834
+	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 22 */
835
+	&sensor_dev_attr_pwm1_enable.dev_attr.attr,	/* 23 */
836
+	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 24 */
837
+	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 25 */
838
+	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 26 */
839
+	&sensor_dev_attr_fan3_input.dev_attr.attr,	/* 27 */
840
+	&sensor_dev_attr_fan3_label.dev_attr.attr,	/* 28 */
841
+	&sensor_dev_attr_pwm3.dev_attr.attr,		/* 29 */
789842 	NULL
790843 };
791844 
792845 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
793846 			      int index)
794847 {
795
-	if (disallow_fan_support && index >= 8)
848
+	if (disallow_fan_support && index >= 20)
796849 		return 0;
797850 	if (disallow_fan_type_call &&
798
-	    (index == 9 || index == 12 || index == 15))
851
+	    (index == 21 || index == 25 || index == 28))
799852 		return 0;
800853 	if (index >= 0 && index <= 1 &&
801854 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
....@@ -809,14 +862,36 @@
809862 	if (index >= 6 && index <= 7 &&
810863 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
811864 		return 0;
812
-	if (index >= 8 && index <= 10 &&
865
+	if (index >= 8 && index <= 9 &&
866
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP5))
867
+		return 0;
868
+	if (index >= 10 && index <= 11 &&
869
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP6))
870
+		return 0;
871
+	if (index >= 12 && index <= 13 &&
872
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP7))
873
+		return 0;
874
+	if (index >= 14 && index <= 15 &&
875
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP8))
876
+		return 0;
877
+	if (index >= 16 && index <= 17 &&
878
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP9))
879
+		return 0;
880
+	if (index >= 18 && index <= 19 &&
881
+	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP10))
882
+		return 0;
883
+
884
+	if (index >= 20 && index <= 23 &&
813885 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
814886 		return 0;
815
-	if (index >= 11 && index <= 13 &&
887
+	if (index >= 24 && index <= 26 &&
816888 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
817889 		return 0;
818
-	if (index >= 14 && index <= 16 &&
890
+	if (index >= 27 && index <= 29 &&
819891 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN3))
892
+		return 0;
893
+
894
+	if (index == 23 && !auto_fan)
820895 		return 0;
821896 
822897 	return attr->mode;
....@@ -848,6 +923,24 @@
848923 	err = i8k_get_temp_type(3);
849924 	if (err >= 0)
850925 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
926
+	err = i8k_get_temp_type(4);
927
+	if (err >= 0)
928
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP5;
929
+	err = i8k_get_temp_type(5);
930
+	if (err >= 0)
931
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP6;
932
+	err = i8k_get_temp_type(6);
933
+	if (err >= 0)
934
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP7;
935
+	err = i8k_get_temp_type(7);
936
+	if (err >= 0)
937
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP8;
938
+	err = i8k_get_temp_type(8);
939
+	if (err >= 0)
940
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP9;
941
+	err = i8k_get_temp_type(9);
942
+	if (err >= 0)
943
+		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP10;
851944 
852945 	/* First fan attributes, if fan status or type is OK */
853946 	err = i8k_get_fan_status(0);
....@@ -987,27 +1080,12 @@
9871080 		},
9881081 	},
9891082 	{
990
-		.ident = "Dell XPS421",
991
-		.matches = {
992
-			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
993
-			DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
994
-		},
995
-	},
996
-	{
9971083 		.ident = "Dell Studio",
9981084 		.matches = {
9991085 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
10001086 			DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
10011087 		},
10021088 		.driver_data = (void *)&i8k_config_data[DELL_STUDIO],
1003
-	},
1004
-	{
1005
-		.ident = "Dell XPS 13",
1006
-		.matches = {
1007
-			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1008
-			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13"),
1009
-		},
1010
-		.driver_data = (void *)&i8k_config_data[DELL_XPS],
10111089 	},
10121090 	{
10131091 		.ident = "Dell XPS M140",
....@@ -1018,10 +1096,10 @@
10181096 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
10191097 	},
10201098 	{
1021
-		.ident = "Dell XPS 15 9560",
1099
+		.ident = "Dell XPS",
10221100 		.matches = {
10231101 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1024
-			DMI_MATCH(DMI_PRODUCT_NAME, "XPS 15 9560"),
1102
+			DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
10251103 		},
10261104 	},
10271105 	{ }
....@@ -1088,6 +1166,57 @@
10881166 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
10891167 		},
10901168 	},
1169
+	{
1170
+		.ident = "Dell XPS 15 L502X",
1171
+		.matches = {
1172
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1173
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L502X"),
1174
+		},
1175
+	},
1176
+	{ }
1177
+};
1178
+
1179
+struct i8k_fan_control_data {
1180
+	unsigned int manual_fan;
1181
+	unsigned int auto_fan;
1182
+};
1183
+
1184
+enum i8k_fan_controls {
1185
+	I8K_FAN_34A3_35A3,
1186
+};
1187
+
1188
+static const struct i8k_fan_control_data i8k_fan_control_data[] = {
1189
+	[I8K_FAN_34A3_35A3] = {
1190
+		.manual_fan = 0x34a3,
1191
+		.auto_fan = 0x35a3,
1192
+	},
1193
+};
1194
+
1195
+static struct dmi_system_id i8k_whitelist_fan_control[] __initdata = {
1196
+	{
1197
+		.ident = "Dell Precision 5530",
1198
+		.matches = {
1199
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1200
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
1201
+		},
1202
+		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1203
+	},
1204
+	{
1205
+		.ident = "Dell Latitude 5480",
1206
+		.matches = {
1207
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1208
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5480"),
1209
+		},
1210
+		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1211
+	},
1212
+	{
1213
+		.ident = "Dell Latitude E6440",
1214
+		.matches = {
1215
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1216
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
1217
+		},
1218
+		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1219
+	},
10911220 	{ }
10921221 };
10931222 
....@@ -1096,7 +1225,7 @@
10961225  */
10971226 static int __init i8k_probe(void)
10981227 {
1099
-	const struct dmi_system_id *id;
1228
+	const struct dmi_system_id *id, *fan_control;
11001229 	int fan, ret;
11011230 
11021231 	/*
....@@ -1156,6 +1285,15 @@
11561285 	i8k_fan_max = fan_max ? : I8K_FAN_HIGH;	/* Must not be 0 */
11571286 	i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
11581287 
1288
+	fan_control = dmi_first_match(i8k_whitelist_fan_control);
1289
+	if (fan_control && fan_control->driver_data) {
1290
+		const struct i8k_fan_control_data *data = fan_control->driver_data;
1291
+
1292
+		manual_fan = data->manual_fan;
1293
+		auto_fan = data->auto_fan;
1294
+		pr_info("enabling support for setting automatic/manual fan control\n");
1295
+	}
1296
+
11591297 	if (!fan_mult) {
11601298 		/*
11611299 		 * Autodetect fan multiplier based on nominal rpm