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From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: [PATCH v1 2/3] regulator: fixed: add support for under-voltage IRQ
Date:   Tue, 10 Oct 2023 10:59:05 +0200
Message-Id: <20231010085906.3440452-2-o.rempel@pengutronix.de>
In-Reply-To: <20231010085906.3440452-1-o.rempel@pengutronix.de>
References: <20231010085906.3440452-1-o.rempel@pengutronix.de>
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Add interrupt support for under-voltage notification. This functionality
can be used on systems capable to detect under-voltage state and having
enough capacity to let the SoC do some emergency preparation.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/regulator/fixed.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
index 55130efae9b8..493dd244e4f4 100644
--- a/drivers/regulator/fixed.c
+++ b/drivers/regulator/fixed.c
@@ -105,6 +105,35 @@ static int reg_is_enabled(struct regulator_dev *rdev)
 	return priv->enable_counter > 0;
 }
 
+static irqreturn_t reg_fixed_under_voltage_irq_handler(int irq, void *data)
+{
+	struct fixed_voltage_data *priv = data;
+	struct regulator_dev *rdev = priv->dev;
+
+	regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE, NULL);
+
+	return IRQ_HANDLED;
+}
+
+static int reg_fixed_get_irqs(struct device *dev,
+			      struct fixed_voltage_data *priv)
+{
+	const char *uv = "under-voltage";
+	int ret;
+
+	ret = fwnode_irq_get_byname(dev_fwnode(dev), "under-voltage");
+	/* This is optional IRQ. Ignore if not found */
+	if (ret < 0)
+		return 0;
+
+	ret = devm_request_threaded_irq(dev, ret, NULL,
+					reg_fixed_under_voltage_irq_handler,
+					IRQF_ONESHOT, uv, priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request %s IRQ\n", uv);
+
+	return 0;
+}
 
 /**
  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
@@ -294,6 +323,10 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 	dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
 		drvdata->desc.fixed_uV);
 
+	ret = reg_fixed_get_irqs(dev, drvdata);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
-- 
2.39.2