linux-kernel - [RFC 5/8] regulator: anatop: fix min dropout for bypass mode

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Message-ID: <cd944a7223cfe68788c299082a5f262e8bea2136.1490199005.git.leonard.crestez@nxp.com>
Date:   Wed, 22 Mar 2017 18:53:07 +0200
From:   Leonard Crestez <leonard.crestez@....com>
To:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>
CC:     Leonard Crestez <leonard.crestez@....com>,
        Robin Gong <yibin.gong@....com>,
        Anson Huang <Anson.Huang@....com>,
        Irina Tirdea <irina.tirdea@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        Octavian Purdila <octavian.purdila@....com>,
        <linux-pm@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [RFC 5/8] regulator: anatop: fix min dropout for bypass mode

From: Irina Tirdea <irina.tirdea@....com>

In bypass mode, the anatop digital regulators do not have any minimum
dropout value (the input voltage is equal to the output voltage according
to documentation).

Having a min dropout value of 125mV will lead to an increased voltage
for PMIC supplies.

Only set minimum dropout value for ldo enabled mode.

Signed-off-by: Irina Tirdea <irina.tirdea@....com>
Signed-off-by: Leonard Crestez <leonard.crestez@....com>
---
 drivers/regulator/anatop-regulator.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c
index b041f27..64554e8 100644
--- a/drivers/regulator/anatop-regulator.c
+++ b/drivers/regulator/anatop-regulator.c
@@ -38,6 +38,8 @@
 #define LDO_POWER_GATE			0x00
 #define LDO_FET_FULL_ON			0x1f
 
+#define LDO_MIN_DROPOUT_UV		125000
+
 struct anatop_regulator {
 	const char *name;
 	u32 control_reg;
@@ -153,6 +155,10 @@ static int anatop_regmap_set_bypass(struct regulator_dev *reg, bool enable)
 
 	sel = enable ? LDO_FET_FULL_ON : anatop_reg->sel;
 	anatop_reg->bypass = enable;
+	if (anatop_reg->bypass)
+		anatop_reg->rdesc.min_dropout_uV = 0;
+	else
+		anatop_reg->rdesc.min_dropout_uV = LDO_MIN_DROPOUT_UV;
 
 	return regulator_set_voltage_sel_regmap(reg, sel);
 }
@@ -264,7 +270,7 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 	rdesc->vsel_reg = sreg->control_reg;
 	rdesc->vsel_mask = ((1 << sreg->vol_bit_width) - 1) <<
 			   sreg->vol_bit_shift;
-	rdesc->min_dropout_uV = 125000;
+	rdesc->min_dropout_uV = LDO_MIN_DROPOUT_UV;
 
 	config.dev = &pdev->dev;
 	config.init_data = initdata;
@@ -286,6 +292,7 @@ static int anatop_regulator_probe(struct platform_device *pdev)
 		if (sreg->sel == LDO_FET_FULL_ON) {
 			sreg->sel = 0;
 			sreg->bypass = true;
+			rdesc->min_dropout_uV = 0;
 		}
 
 		/*
-- 
2.7.4