guess: add guessing touchscreen modules

Signed-off-by: Egor Shestakov <ved@altlinux.org>

guess/touchscreen/README.md

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+# Guess module: touchscreen
+
+This module tries to guess modules for touchscreen devices.

guess/touchscreen/action

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+#!/bin/bash -eu
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+. guess-functions
+
+$TRACE_SOURCE "Processing ..."
+
+# The idea comes from tslib. Touchscreen devices have
+# the INPUT_PROP_DIRECT property, which is determined
+# by the first from zero bit of the property number
+
+INPUT_PROP_DIRECT=1
+bitmask=$((1 << $INPUT_PROP_DIRECT))
+
+for i in "$SYSFS_PATH"/class/input/event*/device/ ; do
+    readline prop "$i"/properties
+
+    if (($prop & $bitmask)); then
+        p="$(readlink -e "$i")"
+
+        while [ "$p" != "$SYSFS_PATH"/devices ]; do
+            if [ -f "$p"/modalias ]; then
+                readline alias "$p"/modalias
+                guess_modalias "$alias"
+            fi
+            p="${p%/*}"
+        done
+    fi
+done

guess/touchscreen/rules.mk

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+# SPDX-License-Identifier: GPL-3.0-or-later
+.PHONY: guess-touchscreen
+
+guess-touchscreen:
+	$V echo "Processing $@ ..."
+	@ GUESS_SUFFIX=rescue:$@ \
+	    $(DETECTDIR)/touchscreen/action
+
+guess: guess-touchscreen