linux-kernel - [PATCH 1/2] platform/x86: panasonic-laptop: de-obfuscate button codes

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Date:   Sun, 12 Jun 2022 11:05:06 +0200
From:   stefan.seyfried@...glemail.com
To:     kenneth.t.chan@...il.com
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        Stefan Seyfried <seife+kernel@...systems.com>
Subject: [PATCH 1/2] platform/x86: panasonic-laptop: de-obfuscate button codes

From: Stefan Seyfried <seife+kernel@...systems.com>

In the definition of panasonic_keymap[] the key codes are given in
decimal, later checks are done with hexadecimal values, which does
not help in understanding the code.
Additionally use two helper variables to shorten the code and make
the logic more obvious.

Signed-off-by: Stefan Seyfried <seife+kernel@...systems.com>
---
 drivers/platform/x86/panasonic-laptop.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index 37850d07987d..ca6137f4000f 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -762,6 +762,8 @@ static void acpi_pcc_generate_keyinput(struct pcc_acpi *pcc)
 	struct input_dev *hotk_input_dev = pcc->input_dev;
 	int rc;
 	unsigned long long result;
+	unsigned int key;
+	unsigned int updown;
 
 	rc = acpi_evaluate_integer(pcc->handle, METHOD_HKEY_QUERY,
 				   NULL, &result);
@@ -770,18 +772,22 @@ static void acpi_pcc_generate_keyinput(struct pcc_acpi *pcc)
 		return;
 	}
 
+	key = result & 0xf;
+	updown = result & 0x80; /* 0x80 == key down; 0x00 = key up */
+
 	/* hack: some firmware sends no key down for sleep / hibernate */
-	if ((result & 0xf) == 0x7 || (result & 0xf) == 0xa) {
-		if (result & 0x80)
+	if (key == 7 || key == 10) {
+		if (updown)
 			sleep_keydown_seen = 1;
 		if (!sleep_keydown_seen)
 			sparse_keymap_report_event(hotk_input_dev,
-					result & 0xf, 0x80, false);
+					key, 0x80, false);
 	}
 
-	if ((result & 0xf) == 0x7 || (result & 0xf) == 0x9 || (result & 0xf) == 0xa) {
+	/* for the magic values, see panasonic_keymap[] above */
+	if (key == 7 || key == 9 || key == 10) {
 		if (!sparse_keymap_report_event(hotk_input_dev,
-						result & 0xf, result & 0x80, false))
+						key, updown, false))
 			pr_err("Unknown hotkey event: 0x%04llx\n", result);
 	}
 }
-- 
2.36.1