From nobody Wed Sep 17 23:49:11 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9CA86C4332F for ; Wed, 14 Dec 2022 12:39:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238127AbiLNMjx (ORCPT ); Wed, 14 Dec 2022 07:39:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238302AbiLNMj0 (ORCPT ); Wed, 14 Dec 2022 07:39:26 -0500 Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C88121E08 for ; Wed, 14 Dec 2022 04:38:08 -0800 (PST) Received: from localhost.localdomain (85-222-111-42.dynamic.chello.pl [85.222.111.42]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: lukma@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 978F385169; Wed, 14 Dec 2022 13:38:06 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1671021487; bh=azo7orbjiRSezN63u1QFsZfaSV1rIV/pBSbsk2QFUuQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TPftpv/VbeTQrvMqbqLhmRtuiZNvMJGxbLDrpQ8ADXPp3FvRUIYsm0CXNFt+46N1E kewJiPCBbL74uQ/zqtkbpGza9v3QmS1f2Ox7BtQolwsxASqF/kpJeVqJkLxY4ZEBlI N4eprHJ00BubbAo8pl93pVWnPm0hXn9e9PSulBgBd1N8I834/dRV3LxlO2yfLRVcl+ dymehn2B7u7L03eb/sv95hriJ18UGDyTeJrIKCfHxOiE4Nym6Ws23uwWrt64gFVXPK rTYJ0YhnJ/O3mk8pmfLsakNruTA9H+Lcu4CQ0DeGE1gfpW/sS1V4QpngjNU0VziuZy 9b3ZbaiiToFEQ== From: Lukasz Majewski To: Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , Charles Keepax , Stephen Kitt Cc: patches@opensource.cirrus.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Lukasz Majewski Subject: [PATCH 4/4] ASoC: wm8940: Read chip ID when wm8940 codec probing Date: Wed, 14 Dec 2022 13:37:43 +0100 Message-Id: <20221214123743.3713843-5-lukma@denx.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221214123743.3713843-1-lukma@denx.de> References: <20221214123743.3713843-1-lukma@denx.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: clamav-milter 0.103.6 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The wm8940 provides the chip ID information via I2C. In this patch this information is read and if not matching expected value, the probe function is aborted. This prevents from using (i.e. inserting) other wm89* modules which use the sam I2C bus address. Signed-off-by: Lukasz Majewski Acked-by: Charles Keepax --- sound/soc/codecs/wm8940.c | 11 +++++++++++ sound/soc/codecs/wm8940.h | 3 +++ 2 files changed, 14 insertions(+) diff --git a/sound/soc/codecs/wm8940.c b/sound/soc/codecs/wm8940.c index 13cb57210b4b..244998ebab4d 100644 --- a/sound/soc/codecs/wm8940.c +++ b/sound/soc/codecs/wm8940.c @@ -769,6 +769,17 @@ static int wm8940_probe(struct snd_soc_component *comp= onent) int ret; u16 reg; =20 + /* + * Check chip ID for wm8940 - value of 0x00 offset + * SOFTWARE_RESET on write + * CHIP_ID on read + */ + reg =3D snd_soc_component_read(component, WM8940_SOFTRESET); + if (reg !=3D WM8940_CHIP_ID) { + dev_err(component->dev, "Wrong wm8940 chip ID: 0x%x\n", reg); + return -ENODEV; + } + ret =3D wm8940_reset(component); if (ret < 0) { dev_err(component->dev, "Failed to issue reset\n"); diff --git a/sound/soc/codecs/wm8940.h b/sound/soc/codecs/wm8940.h index eb051ed29bb8..8fbddcaa7449 100644 --- a/sound/soc/codecs/wm8940.h +++ b/sound/soc/codecs/wm8940.h @@ -98,5 +98,8 @@ struct wm8940_setup_data { /* Bit definitions */ #define WM8940_SPKMUTE BIT(6) =20 +/* Chip ID */ +#define WM8940_CHIP_ID 0x8940 + #endif /* _WM8940_H */ =20 --=20 2.20.1