License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

34 files changed, 34 insertions, 0 deletions

diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 93c769cd99bf..b16b2e9ddc40 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the industrial I/O core.
 #
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 31fba1974e95..703e7c21f547 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O accelerometer drivers
 #
diff --git a/drivers/iio/accel/bmc150-accel.h b/drivers/iio/accel/bmc150-accel.h
index 38a8b11f8c19..ae6118ae11b1 100644
--- a/drivers/iio/accel/bmc150-accel.h
+++ b/drivers/iio/accel/bmc150-accel.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _BMC150_ACCEL_H_
 #define _BMC150_ACCEL_H_
 
diff --git a/drivers/iio/accel/kxsd9-i2c.c b/drivers/iio/accel/kxsd9-i2c.c
index 95e20855d2ef..98fbb628d5bd 100644
--- a/drivers/iio/accel/kxsd9-i2c.c
+++ b/drivers/iio/accel/kxsd9-i2c.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
diff --git a/drivers/iio/accel/kxsd9.h b/drivers/iio/accel/kxsd9.h
index 7e8a28168310..5e3ca212f5be 100644
--- a/drivers/iio/accel/kxsd9.h
+++ b/drivers/iio/accel/kxsd9.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/device.h>
 #include <linux/kernel.h>
 
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9874e05f52d7..9572c1090f35 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for IIO ADC drivers
 #
diff --git a/drivers/iio/adc/qcom-vadc-common.c b/drivers/iio/adc/qcom-vadc-common.c
index 102fc51b10aa..47d24ae5462f 100644
--- a/drivers/iio/adc/qcom-vadc-common.c
+++ b/drivers/iio/adc/qcom-vadc-common.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/bitops.h>
diff --git a/drivers/iio/adc/qcom-vadc-common.h b/drivers/iio/adc/qcom-vadc-common.h
index 63c872a70adc..1d5354ff5c72 100644
--- a/drivers/iio/adc/qcom-vadc-common.h
+++ b/drivers/iio/adc/qcom-vadc-common.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Code shared between the different Qualcomm PMIC voltage ADCs
  */
diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile
index 85beaae831ae..95f9f41c58b7 100644
--- a/drivers/iio/buffer/Makefile
+++ b/drivers/iio/buffer/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the industrial I/O buffer implementations
 #
diff --git a/drivers/iio/common/Makefile b/drivers/iio/common/Makefile
index 6fa760e1bdd5..4bc30bb548e2 100644
--- a/drivers/iio/common/Makefile
+++ b/drivers/iio/common/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the IIO common modules.
 # Common modules contains modules, which can be shared among multiple
diff --git a/drivers/iio/common/ssp_sensors/ssp_iio_sensor.h b/drivers/iio/common/ssp_sensors/ssp_iio_sensor.h
index 541c6590d69c..4528ab55eb68 100644
--- a/drivers/iio/common/ssp_sensors/ssp_iio_sensor.h
+++ b/drivers/iio/common/ssp_sensors/ssp_iio_sensor.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __SSP_IIO_SENSOR_H__
 #define __SSP_IIO_SENSOR_H__
 
diff --git a/drivers/iio/common/st_sensors/Makefile b/drivers/iio/common/st_sensors/Makefile
index 9f3e24f3024b..f7fb3b79b64c 100644
--- a/drivers/iio/common/st_sensors/Makefile
+++ b/drivers/iio/common/st_sensors/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the STMicroelectronics sensor common modules.
 #
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.h b/drivers/iio/common/st_sensors/st_sensors_core.h
index cd88098ff6f1..e8894be55660 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.h
+++ b/drivers/iio/common/st_sensors/st_sensors_core.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Local functions in the ST Sensors core
  */
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 603587cc2f07..993511ba4b17 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O DAC drivers
 #
diff --git a/drivers/iio/dummy/Makefile b/drivers/iio/dummy/Makefile
index 0765e93d7804..f14fe20f365c 100644
--- a/drivers/iio/dummy/Makefile
+++ b/drivers/iio/dummy/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the IIO Dummy Driver
 #
diff --git a/drivers/iio/dummy/iio_dummy_evgen.h b/drivers/iio/dummy/iio_dummy_evgen.h
index d044b946e74a..e0bf64fe9d67 100644
--- a/drivers/iio/dummy/iio_dummy_evgen.h
+++ b/drivers/iio/dummy/iio_dummy_evgen.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _IIO_DUMMY_EVGEN_H_
 #define _IIO_DUMMY_EVGEN_H_
 
diff --git a/drivers/iio/gyro/Makefile b/drivers/iio/gyro/Makefile
index f0e149a606b0..295ec780c4eb 100644
--- a/drivers/iio/gyro/Makefile
+++ b/drivers/iio/gyro/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O gyroscope sensor drivers
 #
diff --git a/drivers/iio/gyro/bmg160.h b/drivers/iio/gyro/bmg160.h
index 72db723c8fb6..6bcff6562249 100644
--- a/drivers/iio/gyro/bmg160.h
+++ b/drivers/iio/gyro/bmg160.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef BMG160_H_
 #define BMG160_H_
 
diff --git a/drivers/iio/gyro/mpu3050.h b/drivers/iio/gyro/mpu3050.h
index bef87a714dc5..835b0249c376 100644
--- a/drivers/iio/gyro/mpu3050.h
+++ b/drivers/iio/gyro/mpu3050.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/iio/iio.h>
 #include <linux/mutex.h>
 #include <linux/regmap.h>
diff --git a/drivers/iio/humidity/Makefile b/drivers/iio/humidity/Makefile
index be0dedeb8f3c..ae4204995017 100644
--- a/drivers/iio/humidity/Makefile
+++ b/drivers/iio/humidity/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for IIO humidity sensor drivers
 #
diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
index 8b563c3323b5..68629c68b19b 100644
--- a/drivers/iio/imu/Makefile
+++ b/drivers/iio/imu/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for Inertial Measurement Units
 #
diff --git a/drivers/iio/imu/adis16400_buffer.c b/drivers/iio/imu/adis16400_buffer.c
index 90c24a23c679..e70a5339acb1 100644
--- a/drivers/iio/imu/adis16400_buffer.c
+++ b/drivers/iio/imu/adis16400_buffer.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
 #include <linux/kernel.h>
diff --git a/drivers/iio/imu/bmi160/bmi160.h b/drivers/iio/imu/bmi160/bmi160.h
index d2ae6ed70271..e7b11e74fd1d 100644
--- a/drivers/iio/imu/bmi160/bmi160.h
+++ b/drivers/iio/imu/bmi160/bmi160.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef BMI160_H_
 #define BMI160_H_
 
diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
index 734af5e6cef9..70ffe0d13d8c 100644
--- a/drivers/iio/imu/inv_mpu6050/Makefile
+++ b/drivers/iio/imu/inv_mpu6050/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for Invensense MPU6050 device.
 #
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index fa32fa459e2e..c263469b7ce9 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for IIO Light sensors
 #
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index b86d6cb7f285..664b2f866472 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O Magnetometer sensor drivers
 #
diff --git a/drivers/iio/magnetometer/bmc150_magn.h b/drivers/iio/magnetometer/bmc150_magn.h
index 9a8e26812ca8..3b69232afd2c 100644
--- a/drivers/iio/magnetometer/bmc150_magn.h
+++ b/drivers/iio/magnetometer/bmc150_magn.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _BMC150_MAGN_H_
 #define _BMC150_MAGN_H_
 
diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile
index 2260d40e0936..1afd1e70f8cc 100644
--- a/drivers/iio/potentiometer/Makefile
+++ b/drivers/iio/potentiometer/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O potentiometer drivers
 #
diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
index 838642789389..c2058d7b2f93 100644
--- a/drivers/iio/pressure/Makefile
+++ b/drivers/iio/pressure/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O pressure drivers
 #
diff --git a/drivers/iio/pressure/bmp280-regmap.c b/drivers/iio/pressure/bmp280-regmap.c
index 6807113ec09f..08c00ac32bda 100644
--- a/drivers/iio/pressure/bmp280-regmap.c
+++ b/drivers/iio/pressure/bmp280-regmap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
index 61347438b779..eda50ef65706 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/regmap.h>
diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
index ed1b6f4cc209..ad6686391f08 100644
--- a/drivers/iio/proximity/Makefile
+++ b/drivers/iio/proximity/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for IIO proximity sensors
 #
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
index ad1d668de546..34bd9023727b 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for industrial I/O temperature drivers
 #
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
index 0a72a2a76cb2..f3d11acb8a0b 100644
--- a/drivers/iio/trigger/Makefile
+++ b/drivers/iio/trigger/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for triggers not associated with iio-devices
 #