selftests: gpio: add test cases for gpio-sim

Add a set of tests for the new gpio-sim module. This is a pure shell
test-suite and uses the helper programs available in the gpio selftests
directory. These test-cases only test the functionalities exposed by the
gpio-sim driver, not those handled by core gpiolib code.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

tools/testing/selftests/gpio/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
-TEST_PROGS := gpio-mockup.sh
+TEST_PROGS := gpio-mockup.sh gpio-sim.sh
 TEST_FILES := gpio-mockup-sysfs.sh
 TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info gpio-line-name
 

tools/testing/selftests/gpio/config

 CONFIG_GPIOLIB=y
 CONFIG_GPIO_CDEV=y
 CONFIG_GPIO_MOCKUP=m
+CONFIG_GPIO_SIM=m

tools/testing/selftests/gpio/gpio-sim.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
+
+BASE_DIR=`dirname $0`
+CONFIGFS_DIR="/sys/kernel/config/gpio-sim"
+MODULE="gpio-sim"
+
+fail() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test FAIL"
+	exit 1
+}
+
+skip() {
+	echo "$*" >&2
+	echo "GPIO $MODULE test SKIP"
+	exit 4
+}
+
+remove_chip() {
+	local CHIP=$1
+
+	for FILE in $CONFIGFS_DIR/$CHIP/*; do
+		BANK=`basename $FILE`
+		if [ "$BANK" == "live" ] || [ "$BANK" == "dev_name" ]; then
+			continue
+		fi
+
+		LINES=`ls $CONFIGFS_DIR/$CHIP/$BANK/ | egrep ^line`
+		if [ "$?" == 0 ]; then
+			for LINE in $LINES; do
+				if [ -e $CONFIGFS_DIR/$CHIP/$BANK/$LINE/hog ]; then
+					rmdir $CONFIGFS_DIR/$CHIP/$BANK/$LINE/hog || \
+						fail "Unable to remove the hog"
+				fi
+
+				rmdir $CONFIGFS_DIR/$CHIP/$BANK/$LINE || \
+					fail "Unable to remove the line"
+			done
+		fi
+
+		rmdir $CONFIGFS_DIR/$CHIP/$BANK
+	done
+
+	rmdir $CONFIGFS_DIR/$CHIP || fail "Unable to remove the chip"
+}
+
+configfs_cleanup() {
+	for CHIP in `ls $CONFIGFS_DIR/`; do
+		remove_chip $CHIP
+	done
+}
+
+create_chip() {
+	local CHIP=$1
+
+	mkdir $CONFIGFS_DIR/$CHIP
+}
+
+create_bank() {
+	local CHIP=$1
+	local BANK=$2
+
+	mkdir $CONFIGFS_DIR/$CHIP/$BANK
+}
+
+set_label() {
+	local CHIP=$1
+	local BANK=$2
+	local LABEL=$3
+
+	echo $LABEL > $CONFIGFS_DIR/$CHIP/$BANK/label || fail "Unable to set the chip label"
+}
+
+set_num_lines() {
+	local CHIP=$1
+	local BANK=$2
+	local NUM_LINES=$3
+
+	echo $NUM_LINES > $CONFIGFS_DIR/$CHIP/$BANK/num_lines || \
+		fail "Unable to set the number of lines"
+}
+
+set_line_name() {
+	local CHIP=$1
+	local BANK=$2
+	local OFFSET=$3
+	local NAME=$4
+	local LINE_DIR=$CONFIGFS_DIR/$CHIP/$BANK/line$OFFSET
+
+	test -d $LINE_DIR || mkdir $LINE_DIR
+	echo $NAME > $LINE_DIR/name || fail "Unable to set the line name"
+}
+
+enable_chip() {
+	local CHIP=$1
+
+	echo 1 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to enable the chip"
+}
+
+disable_chip() {
+	local CHIP=$1
+
+	echo 0 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to disable the chip"
+}
+
+configfs_chip_name() {
+	local CHIP=$1
+	local BANK=$2
+
+	cat $CONFIGFS_DIR/$CHIP/$BANK/chip_name 2> /dev/null || \
+		fail "unable to read the chip name from configfs"
+}
+
+configfs_dev_name() {
+	local CHIP=$1
+
+	cat $CONFIGFS_DIR/$CHIP/dev_name 2> /dev/null || \
+		fail "unable to read the device name from configfs"
+}
+
+get_chip_num_lines() {
+	local CHIP=$1
+	local BANK=$2
+
+	$BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP $BANK` num-lines || \
+		fail "unable to read the number of lines from the character device"
+}
+
+get_chip_label() {
+	local CHIP=$1
+	local BANK=$2
+
+	$BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP $BANK` label || \
+		fail "unable to read the chip label from the character device"
+}
+
+get_line_name() {
+	local CHIP=$1
+	local BANK=$2
+	local OFFSET=$3
+
+	$BASE_DIR/gpio-line-name /dev/`configfs_chip_name $CHIP $BANK` $OFFSET || \
+		fail "unable to read the line name from the character device"
+}
+
+sysfs_set_pull() {
+	local DEV=$1
+	local BANK=$2
+	local OFFSET=$3
+	local PULL=$4
+	local DEVNAME=`configfs_dev_name $DEV`
+	local CHIPNAME=`configfs_chip_name $DEV $BANK`
+	local SYSFSPATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio$OFFSET/pull"
+
+	echo $PULL > $SYSFSPATH || fail "Unable to set line pull in sysfs"
+}
+
+# Load the gpio-sim module. This will pull in configfs if needed too.
+modprobe gpio-sim || skip "unable to load the gpio-sim module"
+# Make sure configfs is mounted at /sys/kernel/config. Wait a bit if needed.
+for IDX in `seq 5`; do
+	if [ "$IDX" -eq "5" ]; then
+		skip "configfs not mounted at /sys/kernel/config"
+	fi
+
+	mountpoint -q /sys/kernel/config && break
+	sleep 0.1
+done
+# If the module was already loaded: remove all previous chips
+configfs_cleanup
+
+trap "exit 1" SIGTERM SIGINT
+trap configfs_cleanup EXIT
+
+echo "1. chip_name and dev_name attributes"
+
+echo "1.1. Chip name is communicated to user"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -n `cat $CONFIGFS_DIR/chip/bank/chip_name` || fail "chip_name doesn't work"
+remove_chip chip
+
+echo "1.2. chip_name returns 'none' if the chip is still pending"
+create_chip chip
+create_bank chip bank
+test "`cat $CONFIGFS_DIR/chip/bank/chip_name`" = "none" || \
+	fail "chip_name doesn't return 'none' for a pending chip"
+remove_chip chip
+
+echo "1.3. Device name is communicated to user"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -n `cat $CONFIGFS_DIR/chip/dev_name` || fail "dev_name doesn't work"
+remove_chip chip
+
+echo "2. Creating and configuring simulated chips"
+
+echo "2.1. Default number of lines is 1"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test "`get_chip_num_lines chip bank`" = "1" || fail "default number of lines is not 1"
+remove_chip chip
+
+echo "2.2. Number of lines can be specified"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 16
+enable_chip chip
+test "`get_chip_num_lines chip bank`" = "16" || fail "number of lines is not 16"
+remove_chip chip
+
+echo "2.3. Label can be set"
+create_chip chip
+create_bank chip bank
+set_label chip bank foobar
+enable_chip chip
+test "`get_chip_label chip bank`" = "foobar" || fail "label is incorrect"
+remove_chip chip
+
+echo "2.4. Label can be left empty"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+test -z "`cat $CONFIGFS_DIR/chip/bank/label`" || fail "label is not empty"
+remove_chip chip
+
+echo "2.5. Line names can be configured"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 16
+set_line_name chip bank 0 foo
+set_line_name chip bank 2 bar
+enable_chip chip
+test "`get_line_name chip bank 0`" = "foo" || fail "line name is incorrect"
+test "`get_line_name chip bank 2`" = "bar" || fail "line name is incorrect"
+remove_chip chip
+
+echo "2.6. Line config can remain unused if offset is greater than number of lines"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 2
+set_line_name chip bank 5 foobar
+enable_chip chip
+test "`get_line_name chip bank 0`" = "" || fail "line name is incorrect"
+test "`get_line_name chip bank 1`" = "" || fail "line name is incorrect"
+remove_chip chip
+
+echo "2.7. Line configfs directory names are sanitized"
+create_chip chip
+create_bank chip bank
+mkdir $CONFIGFS_DIR/chip/bank/line12foobar 2> /dev/null && \
+	fail "invalid configfs line name accepted"
+mkdir $CONFIGFS_DIR/chip/bank/line_no_offset 2> /dev/null && \
+	fail "invalid configfs line name accepted"
+remove_chip chip
+
+echo "2.8. Multiple chips can be created"
+CHIPS="chip0 chip1 chip2"
+for CHIP in $CHIPS; do
+	create_chip $CHIP
+	create_bank $CHIP bank
+	enable_chip $CHIP
+done
+for CHIP in $CHIPS; do
+	remove_chip $CHIP
+done
+
+echo "2.9. Can't modify settings when chip is live"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+echo foobar > $CONFIGFS_DIR/chip/bank/label 2> /dev/null && \
+	fail "Setting label of a live chip should fail"
+echo 8 > $CONFIGFS_DIR/chip/bank/num_lines 2> /dev/null && \
+	fail "Setting number of lines of a live chip should fail"
+remove_chip chip
+
+echo "2.10. Can't create line items when chip is live"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+mkdir $CONFIGFS_DIR/chip/bank/line0 2> /dev/null && fail "Creating line item should fail"
+remove_chip chip
+
+echo "2.11. Probe errors are propagated to user-space"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 99999
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Probe error was not propagated"
+remove_chip chip
+
+echo "2.12. Cannot enable a chip without any GPIO banks"
+create_chip chip
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Chip enabled without any GPIO banks"
+remove_chip chip
+
+echo "2.13. Duplicate chip labels are not allowed"
+create_chip chip
+create_bank chip bank0
+set_label chip bank0 foobar
+create_bank chip bank1
+set_label chip bank1 foobar
+echo 1 > $CONFIGFS_DIR/chip/live 2> /dev/null && fail "Duplicate chip labels were not rejected"
+remove_chip chip
+
+echo "2.14. Lines can be hogged"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+mkdir -p $CONFIGFS_DIR/chip/bank/line4/hog
+enable_chip chip
+$BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 4 2> /dev/null && \
+	fail "Setting the value of a hogged line shouldn't succeed"
+remove_chip chip
+
+echo "3. Controlling simulated chips"
+
+echo "3.1. Pull can be set over sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+sysfs_set_pull chip bank 0 pull-up
+$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 0
+test "$?" = "1" || fail "pull set incorrectly"
+sysfs_set_pull chip bank 0 pull-down
+$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 1
+test "$?" = "0" || fail "pull set incorrectly"
+remove_chip chip
+
+echo "3.2. Pull can be read from sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH=/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull
+test `cat $SYSFS_PATH` = "pull-down" || fail "reading the pull failed"
+sysfs_set_pull chip bank 0 pull-up
+test `cat $SYSFS_PATH` = "pull-up" || fail "reading the pull failed"
+remove_chip chip
+
+echo "3.3. Incorrect input in sysfs is rejected"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull"
+echo foobar > $SYSFS_PATH 2> /dev/null && fail "invalid input not detected"
+remove_chip chip
+
+echo "3.4. Can't write to value"
+create_chip chip
+create_bank chip bank
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
+echo 1 > $SYSFS_PATH 2> /dev/null && fail "writing to 'value' succeeded unexpectedly"
+remove_chip chip
+
+echo "4. Simulated GPIO chips are functional"
+
+echo "4.1. Values can be read from sysfs"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+DEVNAME=`configfs_dev_name chip`
+CHIPNAME=`configfs_chip_name chip bank`
+SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value"
+test `cat $SYSFS_PATH` = "0" || fail "incorrect value read from sysfs"
+$BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 0 &
+sleep 0.1 # FIXME Any better way?
+test `cat $SYSFS_PATH` = "1" || fail "incorrect value read from sysfs"
+kill $!
+remove_chip chip
+
+echo "4.2. Bias settings work correctly"
+create_chip chip
+create_bank chip bank
+set_num_lines chip bank 8
+enable_chip chip
+$BASE_DIR/gpio-mockup-cdev -b pull-up /dev/`configfs_chip_name chip bank` 0
+test `cat $SYSFS_PATH` = "1" || fail "bias setting does not work"
+remove_chip chip
+
+echo "GPIO $MODULE test PASS"