From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 18 Feb 2026 13:43:41 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vsgu4-00338q-0r for lore@lore.pengutronix.de; Wed, 18 Feb 2026 13:43:41 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1vsgu4-0004lM-KF for lore@pengutronix.de; Wed, 18 Feb 2026 13:43:41 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:To:From:Reply-To:Cc:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=txOEjyEfzH4/aAUuLtayMixTS35lmDPnjenFoKjBAps=; b=L5WOQnrRKzgZyq4XkxWXHzX6FZ 85DAONSswdxQWruzwajDxtAIf/wlmwFsm465k1k3v92CxFG9jLC9dT+eLx6Z3my2v/Pi5Irq4koZD okWdLddfftWmjbUcffLpOGFzpJ3auD/slV/5XUMvinoPyTcNy8z3r9WD1d5sctYO/e1OYqtN0k5Lz xPaKuueVRWbA2r00IFonGTTknyIF8LSmagFAnDniCA0nVakCriXaZvYUF/DEjZ+TfKEtd74CFJYzO FXeoX33F3ZRzflkmejjoRDYpxArPUKy7HW008k8MwbCAwuY54xBekFLmRJum+eP+jF8oF0q9fXdIa sX2P1Slw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vsgte-00000009nnP-1SyH; Wed, 18 Feb 2026 12:43:14 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vsgtc-00000009nmi-07yx for barebox@lists.infradead.org; Wed, 18 Feb 2026 12:43:13 +0000 Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1vsgtZ-0004hW-2z for barebox@lists.infradead.org; Wed, 18 Feb 2026 13:43:09 +0100 From: Marco Felsch To: barebox@lists.infradead.org Date: Wed, 18 Feb 2026 13:42:48 +0100 Message-ID: <20260218124307.2358552-1-m.felsch@pengutronix.de> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260218_044312_068759_F58AFE83 X-CRM114-Status: UNSURE ( 9.53 ) X-CRM114-Notice: Please train this message. X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-3.9 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH] eeprom: at24: verify that chip is accessible during probe X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Perform a basic sanity check to verify that the EEPROM is actually accessible by reading 1-byte. Linux does the same sanity check for all non-ACPI platforms. Signed-off-by: Marco Felsch --- drivers/eeprom/at24.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/eeprom/at24.c b/drivers/eeprom/at24.c index 06a2a4b22697..a08d42fe3e14 100644 --- a/drivers/eeprom/at24.c +++ b/drivers/eeprom/at24.c @@ -373,6 +373,7 @@ static int at24_probe(struct device *dev) unsigned i, num_addresses; const char *devname; const char *alias; + u8 test_byte; if (dev->platform_data) { chip = *(struct at24_platform_data *)dev->platform_data; @@ -487,6 +488,12 @@ static int at24_probe(struct device *dev) at24->nvmem_config.size = chip.byte_len; at24->nvmem_config.id = devid; + /* Perform a one-byte test read to verify that the chip is functional */ + if (at24_read(at24, &test_byte, 0, 1) != 1) { + err = -ENODEV; + goto err_devfs_create; + } + at24->nvmem = nvmem_register(&at24->nvmem_config); err = PTR_ERR_OR_ZERO(at24->nvmem); if (err) -- 2.47.3