From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.3]) (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 A494830594E; Wed, 5 Aug 2026 06:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.3 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785910669; cv=none; b=QoSqSmAkqeQpS0HDg0F6PS+f29BxCZjiGOsnmii+FF2TVaEL+iyaQ7nbbVZj9/MbpfU6ucqwFNhq8G15VlZmUJO+1DAm0gTUA1XKnpuC+2KKHCUgbGZ076oYah0YrFC5WyMCC7uRe0AkGq8+mJod3M92xmWsKi7I8WfDM4rOZb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785910669; c=relaxed/simple; bh=lhzLqsrndnNJhWgkqKmgG6tcM3mBtatoSFldp/c8Vhw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gZMJGSwcpxOqSYukfN1GaXS5YDGiQsN1farDwCWuxUAGrH4f0QFnC6bB4g2vd1wdLuDiD4g9xVhlqp4EdVTC8CR35iua9A3zUkB6Vv+NTu364wSXU9yYFfC3+EenJkpbs2whBUWaP3+zdkIHAEMZpQ5E68cAOtyCgz9/e3kNPhI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=aH3fWfc+; arc=none smtp.client-ip=220.197.31.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="aH3fWfc+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=S8 Y7wmETonOkBVlAyxxvjrp4BxFFLhG4WbKKcCtgQ1s=; b=aH3fWfc+10NLjd3gUJ BXBh56rKPPW/j0013S3pqBnKsd2CRjU5KaLgFvvHh50Ah061xcUjdgct6jqGhhsk +C08v20gqAQIGHVEhgqk0m+p4NlYNR32RewYTl5eI+6mlR87FkUNDhWvxjR+1HQc QHK5wGRFBtDf0e/acDzvtSzKs= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-2 (Coremail) with SMTP id _____wD3f3VQ1XJq+86dNQ--.40182S2; Wed, 05 Aug 2026 14:16:49 +0800 (CST) From: Qingshuang Fu To: Guenter Roeck , Liam Girdwood , Mark Brown , Sam Povilus Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, Qingshuang Fu , Qingshuang Fu Subject: [PATCH v4] hwmon: (ads7828) Fix external VREF regulator handling Date: Wed, 5 Aug 2026 14:16:45 +0800 Message-Id: <20260805061645.1331652-1-fffsqian@163.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wD3f3VQ1XJq+86dNQ--.40182S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxZFy8CrW3trWfCry3Gw4UJwb_yoW5WF13pr WkGF9rZr48AFy8WrWxAFW2q3WFq3W8Jws5CFykGw4av3Z8JFyfWr9IkFyYyF17C3yku3W2 vryqyay8Ka9rJFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pRHvV_UUUUU= X-CM-SenderInfo: 5iii21xldqqiywtou0bp/xtbCwRHAi2py1VHa8AAA3t From: Qingshuang Fu The driver currently has two issues with the external VREF regulator handling in ads7828_probe(): 1. All errors from devm_regulator_get_optional() are ignored, causing the driver to incorrectly fall back to internal VREF even for transient errors like -EPROBE_DEFER or genuine failures like -ENOMEM. 2. The external regulator is never enabled. The driver calls regulator_get_voltage() without first calling regulator_enable(), so the VREF pin may remain unpowered if the regulator is not configured as always-on. Fix both issues by switching to devm_regulator_get_enable_read_voltage(), which handles regulator get, enable, and voltage read in one call. Only -ENODEV (no regulator specified in device tree) should trigger the fallback to internal VREF. All other errors are propagated to the caller. Fixes: a8ddfea09566 ("hwmon: (ads7828) Accept optional parameters from device tree") Signed-off-by: Qingshuang Fu --- Changes in v4: - Invert the control flow to check errors first (if (vref_uv < 0) { ... } else { ... }), as requested by Guenter Roeck. Changes in v3: - Switch to devm_regulator_get_enable_read_voltage() to also enable the external regulator, as suggested by Guenter Roeck. Changes in v2: - Broaden the error check to handle all errors except -ENODEV, instead of only checking for -EPROBE_DEFER. This addresses the Sashiko AI review concern about masking genuine errors like -ENOMEM and -EINVAL. drivers/hwmon/ads7828.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c index 149cfcec78dc..f8f2f621dfea 100644 --- a/drivers/hwmon/ads7828.c +++ b/drivers/hwmon/ads7828.c @@ -106,12 +106,11 @@ static int ads7828_probe(struct i2c_client *client) struct ads7828_data *data; struct device *hwmon_dev; unsigned int vref_mv = ADS7828_INT_VREF_MV; - unsigned int vref_uv; + int vref_uv; bool diff_input = false; bool ext_vref = false; unsigned int regval; enum ads7828_chips chip; - struct regulator *reg; data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL); if (!data) @@ -125,9 +124,11 @@ static int ads7828_probe(struct i2c_client *client) } else if (dev->of_node) { diff_input = of_property_read_bool(dev->of_node, "ti,differential-input"); - reg = devm_regulator_get_optional(dev, "vref"); - if (!IS_ERR(reg)) { - vref_uv = regulator_get_voltage(reg); + vref_uv = devm_regulator_get_enable_read_voltage(dev, "vref"); + if (vref_uv < 0) { + if (vref_uv != -ENODEV) + return vref_uv; + } else { vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000); if (vref_mv < ADS7828_EXT_VREF_MV_MIN || vref_mv > ADS7828_EXT_VREF_MV_MAX) -- 2.25.1