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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 13/49] regulator: pwm: Fix machine constraints application
Date:   Mon, 21 Sep 2020 18:27:57 +0200
Message-Id: <20200921162035.250314532@linuxfoundation.org>
In-Reply-To: <20200921162034.660953761@linuxfoundation.org>
References: <20200921162034.660953761@linuxfoundation.org>
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From: Vincent Whitchurch <vincent.whitchurch@axis.com>

[ Upstream commit 59ae97a7a9e1499c2070e29841d1c4be4ae2994a ]

If the zero duty cycle doesn't correspond to any voltage in the voltage
table, the PWM regulator returns an -EINVAL from get_voltage_sel() which
results in the core erroring out with a "failed to get the current
voltage" and ending up not applying the machine constraints.

Instead, return -ENOTRECOVERABLE which makes the core set the voltage
since it's at an unknown value.

For example, with this device tree:

	fooregulator {
		compatible = "pwm-regulator";
		pwms = <&foopwm 0 100000>;
		regulator-min-microvolt = <2250000>;
		regulator-max-microvolt = <2250000>;
		regulator-name = "fooregulator";
		regulator-always-on;
		regulator-boot-on;
		voltage-table = <2250000 30>;
	};

Before this patch:

  fooregulator: failed to get the current voltage(-22)

After this patch:

  fooregulator: Setting 2250000-2250000uV
  fooregulator: 2250 mV

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20200902130952.24880-1-vincent.whitchurch@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/regulator/pwm-regulator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index a2fd140eff81a..34f3b9778ffa1 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -285,7 +285,7 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 		return ret;
 	}
 
-	drvdata->state			= -EINVAL;
+	drvdata->state			= -ENOTRECOVERABLE;
 	drvdata->duty_cycle_table	= duty_cycle_table;
 	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 	       sizeof(drvdata->ops));
-- 
2.25.1