From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DD357348C55; Sat, 30 May 2026 17:24:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161884; cv=none; b=PP6i7E1TwlEfuNL7I87ThcbPGhLILk7T1W/ckLaTCZ4UHCHxzpnmH/MuUl7LqTzYh2aeT4cQnroQX4bOM4i5rZvI2L4ffiK2HMkV7rhV8MYix1R/IUc34aNdqg+q/8PvtkMjG1Yrkeh9olHkVEXXP1VJL0ctaEZmbcKw5S/YlOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161884; c=relaxed/simple; bh=AhxfZ/32oZ4lddNgoGHqiGYcnAGDzA41mZhPTtnNehU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VM5MQwIWV0iFwsCEHtDY0JuhiP+Awe2MEUW/urTrpMJUgQIlZn8B5jcPxMAQq9jpFnm7QkKqPPEwONSCqutSxI6uiWHtPx3FmazwAGpUJNUg3VrZhV4n3LKeYpPQ0t/5BLo4boji+txAcmOX167XOGnDQsV5PbgLfa1jLJwfcWU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xLXo0mKc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xLXo0mKc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDD1A1F00893; Sat, 30 May 2026 17:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780161882; bh=21GLyUZFq1AWMRnMVSntb3kAdv7pjZhEs712V3SMK9s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xLXo0mKctzgetY1EZuHmrmuKPVyCxv62GzHpIw2T8kor/TPCAMTMduKdGHl6MvJVG DqRbb+RXWdlKlum+WrwYLKAIFR6ugXjpHfdO7f2MNUiAU0uoLz7bT4zltYi2vPFZTp CIQfsbGGnFDp0cFG7NfwaesUarBVRLBaiunnBmMo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paul Geurts , Krzysztof Kozlowski , Mark Greer , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 755/969] NFC: trf7970a: Ignore antenna noise when checking for RF field Date: Sat, 30 May 2026 18:04:39 +0200 Message-ID: <20260530160321.413442386@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Geurts [ Upstream commit a9bc28aa4e64320668131349436a650bf42591a5 ] The main channel Received Signal Strength Indicator (RSSI) measurement is used to determine whether an RF field is present or not. RSSI != 0 is interpreted as an RF Field is present. This does not take RF noise and measurement inaccuracy into account, and results in false positives in the field. Define a noise level and make sure the RF field is only interpreted as present when the RSSI is above the noise level. Fixes: 851ee3cbf850 ("NFC: trf7970a: Don't turn on RF if there is already an RF field") Signed-off-by: Paul Geurts Reviewed-by: Krzysztof Kozlowski Reviewed-by: Mark Greer Link: https://patch.msgid.link/20260422100930.581237-1-paul.geurts@prodrive-technologies.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/nfc/trf7970a.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index 7968baa626d16..b7a8d525e3c29 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -311,6 +311,7 @@ #define TRF7970A_RSSI_OSC_STATUS_RSSI_MASK (BIT(2) | BIT(1) | BIT(0)) #define TRF7970A_RSSI_OSC_STATUS_RSSI_X_MASK (BIT(5) | BIT(4) | BIT(3)) #define TRF7970A_RSSI_OSC_STATUS_RSSI_OSC_OK BIT(6) +#define TRF7970A_RSSI_OSC_STATUS_RSSI_NOISE_LEVEL 1 #define TRF7970A_SPECIAL_FCN_REG1_COL_7_6 BIT(0) #define TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL BIT(1) @@ -1253,7 +1254,7 @@ static int trf7970a_is_rf_field(struct trf7970a *trf, bool *is_rf_field) if (ret) return ret; - if (rssi & TRF7970A_RSSI_OSC_STATUS_RSSI_MASK) + if ((rssi & TRF7970A_RSSI_OSC_STATUS_RSSI_MASK) > TRF7970A_RSSI_OSC_STATUS_RSSI_NOISE_LEVEL) *is_rf_field = true; else *is_rf_field = false; -- 2.53.0