linux-kernel - [PATCH RFC v4 07/13] regulator: find active protections during initialization

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Message-Id: <20230419-dynamic-vmon-v4-7-4d3734e62ada@skidata.com>
Date:   Tue, 20 Jun 2023 22:03:00 +0200
From:   Benjamin Bara <bbara93@...il.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     support.opensource@...semi.com,
        DLG-Adam.Ward.opensource@...renesas.com,
        Martin Fuzzey <martin.fuzzey@...wbird.group>,
        linux-kernel@...r.kernel.org,
        Matti Vaittinen <mazziesaccount@...il.com>,
        Benjamin Bara <benjamin.bara@...data.com>
Subject: [PATCH RFC v4 07/13] regulator: find active protections during
 initialization

From: Benjamin Bara <benjamin.bara@...data.com>

It can happen that monitors are activated before the kernel is started,
e.g. by bootloader or by OTP. If monitoring workarounds are active on a
regulator, the core shouldn't perform the state changes without applying
the workaround to the regulator. Therefore, warn the user already during
initialization that the device-tree should be adapted.

Warning can be fixed by enabling (or disabling) monitoring in the DT,
e.g.:
regulator-uv-protection-microvolt = <1>;
or
regulator-ov-error-microvolt = <0>;

Constraints regarding the monitoring of a regulator can usually be found
in the docu.

Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>
---
 drivers/regulator/core.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ca5d6ba889dc..9bddab17450e 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1564,6 +1564,47 @@ static int set_machine_constraints(struct regulator_dev *rdev)
 		}
 	}
 
+	/*
+	 * When the core is in charge of handling monitoring workarounds,
+	 * it is essential to know if a monitor is already active during
+	 * initialization.
+	 */
+	if (rdev->desc->mon_disable_reg_disabled ||
+	    rdev->desc->mon_disable_reg_set_higher ||
+	    rdev->desc->mon_disable_reg_set_lower ||
+	    rdev->desc->mon_unsupported_reg_modes) {
+		unsigned int monitor_state = REGULATOR_MONITOR_NONE;
+
+		ret = ops->get_active_protections(rdev, &monitor_state);
+		if (ret)
+			return ret;
+
+		if (!rdev->constraints->over_voltage_detection &&
+		    (monitor_state & REGULATOR_MONITOR_OVER_VOLTAGE)) {
+			rdev_err(rdev, "dt unaware of active %s monitor!\n",
+				       "over-voltage");
+			return -EINVAL;
+		}
+		if (!rdev->constraints->under_voltage_detection &&
+		    (monitor_state & REGULATOR_MONITOR_UNDER_VOLTAGE)) {
+			rdev_err(rdev, "dt unaware of active %s monitor!\n",
+				       "under-voltage");
+			return -EINVAL;
+		}
+		if (!rdev->constraints->over_current_detection &&
+		    (monitor_state & REGULATOR_MONITOR_OVER_CURRENT)) {
+			rdev_err(rdev, "dt unaware of active %s monitor!\n",
+				       "over-current");
+			return -EINVAL;
+		}
+		if (!rdev->constraints->over_temp_detection &&
+		    (monitor_state & REGULATOR_MONITOR_OVER_TEMPERATURE)) {
+			rdev_err(rdev, "dt unaware of active %s monitor!\n",
+				       "over-temperature");
+			return -EINVAL;
+		}
+	}
+
 	if (rdev->constraints->over_current_detection)
 		ret = handle_notify_limits(rdev,
 					   ops->set_over_current_protection,

-- 
2.34.1