From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1CD1815820C; Tue, 11 Mar 2025 15:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741706205; cv=none; b=I+YK2zSbf6g4DiVrEt4HoCYh1bAi2yQ9DFdCrbf5+Dy9uo6V5+HUv5VkiJzUns3ckRxCLbihHo8BgV9mvTyvWKsy67U1XN8oxdHgrHimmcHcov7jfE4zPKv8ueXdTZyv9HGGaNLr0RaCeYfptjQLLzbZT4euM1NRon5A3149jsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741706205; c=relaxed/simple; bh=Ph+ubgudyPSCPwmkFZidSH9W5kIBWQ9iaAzKbIGYuWA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uNWW1iEOdhShw4WInrqw3pE8sju/3Fxt4Jmvaj6WqkBYcKlfgM+rMeW+cnDG1PUAy+ouZIDaT8hHFy970FFwkKA8cCzyrvii0yACkol2DkQbcvf1UGzkAmUMmhRdI1bBoqKrQzgBXyLydVKB1jlfhX3i9H1m1QjgiILu1pOjAms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Bp1QIuMM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Bp1QIuMM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B17FC4CEE9; Tue, 11 Mar 2025 15:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741706205; bh=Ph+ubgudyPSCPwmkFZidSH9W5kIBWQ9iaAzKbIGYuWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bp1QIuMMyc6SqiapcJ4rEgZ9joEjUGNYznkkRsKN3DcR4wwi+PoVdfYtBWzij1o8z u2tqVkpE/BU6pvMDiQSuMGBxTnZkt5w/fQTFMMsDTLDaSExP3friYM7FP+xP8bNQvd q/WY02qw6bSwXZ+KbNZumyj+PzJZhf9opjmXKmIw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Titus Rwantare , Guenter Roeck , Sasha Levin Subject: [PATCH 5.4 298/328] hwmon: (pmbus) Initialise page count in pmbus_identify() Date: Tue, 11 Mar 2025 16:01:08 +0100 Message-ID: <20250311145726.748757710@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145714.865727435@linuxfoundation.org> References: <20250311145714.865727435@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Titus Rwantare [ Upstream commit 6b6e2e8fd0de3fa7c6f4f8fe6841b01770b2e7bc ] The `pmbus_identify()` function fails to correctly determine the number of supported pages on PMBus devices. This occurs because `info->pages` is implicitly zero-initialised, and `pmbus_set_page()` does not perform writes to the page register if `info->pages` is not yet initialised. Without this patch, `info->pages` is always set to the maximum after scanning. This patch initialises `info->pages` to `PMBUS_PAGES` before the probing loop, enabling `pmbus_set_page()` writes to make it out onto the bus correctly identifying the number of pages. `PMBUS_PAGES` seemed like a reasonable non-zero number because that's the current result of the identification process. Testing was done with a PMBus device in QEMU. Signed-off-by: Titus Rwantare Fixes: 442aba78728e7 ("hwmon: PMBus device driver") Link: https://lore.kernel.org/r/20250227222455.2583468-1-titusr@google.com Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- drivers/hwmon/pmbus/pmbus.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/hwmon/pmbus/pmbus.c b/drivers/hwmon/pmbus/pmbus.c index c0bc43d010186..81d4e9e85d3ea 100644 --- a/drivers/hwmon/pmbus/pmbus.c +++ b/drivers/hwmon/pmbus/pmbus.c @@ -101,6 +101,8 @@ static int pmbus_identify(struct i2c_client *client, if (pmbus_check_byte_register(client, 0, PMBUS_PAGE)) { int page; + info->pages = PMBUS_PAGES; + for (page = 1; page < PMBUS_PAGES; page++) { if (pmbus_set_page(client, page) < 0) break; -- 2.39.5