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 DB7563C1082; Wed, 16 Sep 2026 21:05:22 +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=1789592738; cv=none; b=Y52pb73flFGKB/b4FTwSSeh+zRUSujQaehbaL4nlBabj12EWfjb90t0ca0qe+Q7MCel6WMe6qQv93TGOo5HukUKT5hCtSeDYYLx67+wWbyEEkoh6mvNtVc5aofOyOwyIGOmWjxiEs+wYREQZtn9rV20cg18JsyDWzjguupLU74g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789592738; c=relaxed/simple; bh=ym8Mn69WwsoUw+FEJrRP/a/gIZFRUAApM5SNiDbIZfs=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=AIaQRG80GUeW2hTKOM1x4D8a1SHlMuxJ+K/jqraawam9uH2lDRAwYq3MUjHQG7rsHDiINoUYDvFgYooPfyjOk/AMxzWMF+Xn6ddB7iLL5bazciQt5kqFYe8xqXg/OUTOg1EqXUSNBhTKYZEzxEFgcaswP0dxe9YRIsRci5ho7ZM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C7c2NGLp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="C7c2NGLp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96B6A1F000FF; Wed, 16 Sep 2026 21:05:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789592720; bh=bUixq2NWUuTmrM/rpny4As14DsG1jrVEKpVkZkXCu4M=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=C7c2NGLpXs4Mdfk5pK0rbmhjF7/CQCYxU9gDdejcpVTHY568ZqJcFx+TBR5L4blPH FvfDs0CpKfHpmEN0obyE+jwcd3FcOjVauiPCnw9wDSe6Xi0FBHFrHNOO1yholvUC/j BPEsKxbGdEhKdCsSRTemXyYFKNlI640s1PLMtV3X/Edi02jb45TuVDNMPYHX73KHgw B+70SToksSn0VgyYgieur0thTGkPWVAVvyFQ7eCec5hF9IhOFhiBVIC4TqPRtXosz9 5uxHJGd9YapE4bomqz+O434t4+0iErTdxQ7s7xDtfuJtIhC/7vS6uSkRIxhjATPhVH L21EU5Caprd0Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v7 7/9] rtc: abx80x: replace read-modify-write pattern with regmap helpers Reply-To: sashiko-reviews@lists.linux.dev To: "Antoni Pokusinski" Cc: linux-rtc@vger.kernel.org, "Alexandre Belloni" , devicetree@vger.kernel.org, robh@kernel.org, conor+dt@kernel.org In-Reply-To: <20260916205138.16771-8-apokusinski01@gmail.com> References: <20260916205138.16771-1-apokusinski01@gmail.com> <20260916205138.16771-8-apokusinski01@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 16 Sep 2026 21:05:20 +0000 Message-Id: <20260916210520.96B6A1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] rtc: abx80x: hardware unlock broken by regmap RMW helpers -- commit aad0cc39d854acf9e4ccd3b1fa7b17484a428c9a Author: Antoni Pokusinski rtc: abx80x: replace read-modify-write pattern with regmap helpers This commit refactors the driver to replace open-coded read-modify-write sequences with the regmap_update_bits() and regmap_write_bits() helpers to simplify the code. > diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c > --- a/drivers/rtc/rtc-abx80x.c > +++ b/drivers/rtc/rtc-abx80x.c [ ... ] > @@ -403,13 +388,15 @@ static int abx80x_rtc_set_autocalibration(struct de= vice *dev, > flags |=3D (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512); > } > =20 > + guard(mutex)(&priv->lock); > + > /* Unlock write access to Oscillator Control Register */ > if (abx80x_write_config_key(dev, ABX8XX_CFG_KEY_OSC) < 0) > return -EIO; > =20 > - retval =3D regmap_write(priv->regmap, ABX8XX_REG_OSC, flags); > - > - return retval; > + return regmap_write_bits(priv->regmap, ABX8XX_REG_OSC, > + ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512, > + flags); > } [Severity: High] Since regmap_write_bits() performs an internal read-modify-write cycle, will the initial read operation consume the configuration key unlock?=20 It looks like writing the configuration key only unlocks the very next=20 transaction. If the regmap helper reads first, the actual write might fail= =20 silently and the hardware would reject the autocalibration settings. [ ... ] > @@ -486,24 +472,14 @@ static ssize_t oscillator_store(struct device *dev, > =20 > guard(mutex)(&priv->lock); > =20 > - retval =3D regmap_read(priv->regmap, ABX8XX_REG_OSC, &flags); > - if (retval < 0) > - return retval; > - > - if (rc_mode =3D=3D 0) > - flags &=3D ~(ABX8XX_OSC_OSEL); > - else > - flags |=3D (ABX8XX_OSC_OSEL); > - > /* Unlock write access on Oscillator Control register */ > if (abx80x_write_config_key(dev->parent, ABX8XX_CFG_KEY_OSC) < 0) > return -EIO; > =20 > - retval =3D regmap_write(priv->regmap, ABX8XX_REG_OSC, flags); > - if (retval < 0) { > + retval =3D regmap_write_bits(priv->regmap, ABX8XX_REG_OSC, ABX8XX_OSC_O= SEL, > + rc_mode =3D=3D 0 ? 0 : (ABX8XX_OSC_OSEL)); > + if (retval < 0) > dev_err(dev, "Failed to write Oscillator Control register\n"); [Severity: High] Does the same issue apply here in oscillator_store()? The internal read=20 within regmap_write_bits() may consume the unlock key, preventing the=20 oscillator selection from being properly updated. [ ... ] > @@ -946,8 +889,14 @@ static int abx80x_probe(struct i2c_client *client) > if (abx80x_write_config_key(&client->dev, ABX8XX_CFG_KEY_MISC) < 0) > return -EIO; > =20 > - err =3D regmap_write(regmap, ABX8XX_REG_OUT_CTRL, > - data | ABX8XX_OUT_CTRL_EXDS); > + /* > + * Avoid extra power leakage. The RV1805 uses smaller > + * 10pin package and the EXTI input is not present. > + * Disable it to avoid leakage. > + */ > + err =3D regmap_write_bits(regmap, ABX8XX_REG_OUT_CTRL, > + ABX8XX_OUT_CTRL_EXDS, > + ABX8XX_OUT_CTRL_EXDS); > if (err < 0) { [Severity: High] Could this cause the power leakage mitigation write in abx80x_probe() to be= =20 rejected by the hardware because the unlock transaction was already consume= d=20 by the regmap_write_bits() read phase? [ ... ] > @@ -1014,11 +949,10 @@ static int abx80x_probe(struct i2c_client *client) > if (abx80x_write_config_key(client, ABX8XX_CFG_KEY_OSC) < 0) > return -EIO; > =20 > - err =3D regmap_write(regmap, ABX8XX_REG_OSC, > - data & ~(ABX8XX_OSC_ACIE | > - ABX8XX_OSC_OFIE)); > + err =3D regmap_write_bits(regmap, ABX8XX_REG_OSC, > + ABX8XX_OSC_ACIE | ABX8XX_OSC_OFIE, 0); > if (err < 0) { [Severity: High] Will the interrupt disable write also fail silently here due to the unlock= =20 being consumed by the regmap read? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260916205138.1677= 1-1-apokusinski01@gmail.com?part=3D7