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 2FFA9401483; Wed, 20 May 2026 18:47:57 +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=1779302880; cv=none; b=c+JKZLyJ0AGDXHeGskluYTgw+S29GvxWro9LzrJBCcoTWgxEOQRlhuzbk9YzRKfQ+bzCSPvsJ5WpPvsWF7r/TddqkFb2qWPe+aawzLloMOPN92mMiIoO/cc7DTK7vDBc6GzUnohof5YX5naKxBLpP7TBmhjUn2gZKzJC8QbjdYM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779302880; c=relaxed/simple; bh=NAKLJXaclNikJUxWwSQJ6MmTIT2xLhw4PX2H22Y2uus=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JxF19QuLrRZQkM38bTNK4Np8Ja5TriNA3CDjFtVcYTn7FWsjJfE/kdzq7KxAg9G23HBJ7pbWyOaEWX8oENTgvHU2YEh+mu37JEVK4QJa+2iAgMzqBXWDXOAXQQlM0tbm1+OLP9N+MR8qsYV6cKXULs0ZaLONQ57opVByuBqX+78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cZPh6g78; 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="cZPh6g78" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D0611F000E9; Wed, 20 May 2026 18:47:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779302877; bh=AMe+69X8Zqe9jnVvz/nZ/lYr5+zwaRYyajbMlyemT/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cZPh6g78+ou0AqwTtEZsDl7VON17BOKAJMJ7HA9z/FpTrfnEY0b9n9Uel+UDLIjaK QiStZWJ/ruTt0xyMHeMO9Jy5ViZiQT7I5OVEMn1OeMECdUmgVCyJiikcKPoB9I0I5S 56uR8PhYUVi6ihJBnJqKOSXi8B4JfXELXaTXPRf0= 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 6.6 392/508] NFC: trf7970a: Ignore antenna noise when checking for RF field Date: Wed, 20 May 2026 18:23:35 +0200 Message-ID: <20260520162107.108119595@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162058.573354582@linuxfoundation.org> References: <20260520162058.573354582@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 6.6-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 9e1a34e23af26..6b8311f526a5e 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