linux-kernel - [PATCH v2] regulator: wm8994: Add an off-on delay for WM8994 variant

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Message-ID: <CY4PR04MB056771CFB80DC447C30D5A31CB1D9@CY4PR04MB0567.namprd04.prod.outlook.com>
Date:   Sun, 27 Mar 2022 18:01:54 -0700
From:   Jonathan Bakker <xc-racer2@...e.ca>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     patches@...nsource.cirrus.com, linux-kernel@...r.kernel.org,
        Jonathan Bakker <xc-racer2@...e.ca>
Subject: [PATCH v2] regulator: wm8994: Add an off-on delay for WM8994 variant

As per Table 130 of the wm8994 datasheet at [1], there is an off-on
delay for LDO1 and LDO2.  In the wm8958 datasheet [2], I could not
find any reference to it.  I could not find a wm1811 datasheet to
double-check there, but as no one has complained presumably it works
without it.

This solves the issue on Samsung Aries boards with a wm8994 where
register writes fail when the device is powered off and back-on
quickly.

[1] https://statics.cirrus.com/pubs/proDatasheet/WM8994_Rev4.6.pdf
[2] https://statics.cirrus.com/pubs/proDatasheet/WM8958_v3.5.pdf

Signed-off-by: Jonathan Bakker <xc-racer2@...e.ca>
---
Changes in v2
- Duplicate regulator_desc, keep it const, and select which one
  instead of modifying the one existing one
---
 drivers/regulator/wm8994-regulator.c | 42 ++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/wm8994-regulator.c b/drivers/regulator/wm8994-regulator.c
index cadea0344486..40befdd9dfa9 100644
--- a/drivers/regulator/wm8994-regulator.c
+++ b/drivers/regulator/wm8994-regulator.c
@@ -71,6 +71,35 @@ static const struct regulator_ops wm8994_ldo2_ops = {
 };
 
 static const struct regulator_desc wm8994_ldo_desc[] = {
+	{
+		.name = "LDO1",
+		.id = 1,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = WM8994_LDO1_MAX_SELECTOR + 1,
+		.vsel_reg = WM8994_LDO_1,
+		.vsel_mask = WM8994_LDO1_VSEL_MASK,
+		.ops = &wm8994_ldo1_ops,
+		.min_uV = 2400000,
+		.uV_step = 100000,
+		.enable_time = 3000,
+		.off_on_delay = 36000,
+		.owner = THIS_MODULE,
+	},
+	{
+		.name = "LDO2",
+		.id = 2,
+		.type = REGULATOR_VOLTAGE,
+		.n_voltages = WM8994_LDO2_MAX_SELECTOR + 1,
+		.vsel_reg = WM8994_LDO_2,
+		.vsel_mask = WM8994_LDO2_VSEL_MASK,
+		.ops = &wm8994_ldo2_ops,
+		.enable_time = 3000,
+		.off_on_delay = 36000,
+		.owner = THIS_MODULE,
+	},
+};
+
+static const struct regulator_desc wm8958_ldo_desc[] = {
 	{
 		.name = "LDO1",
 		.id = 1,
@@ -172,9 +201,16 @@ static int wm8994_ldo_probe(struct platform_device *pdev)
 	 * regulator core and we need not worry about it on the
 	 * error path.
 	 */
-	ldo->regulator = devm_regulator_register(&pdev->dev,
-						 &wm8994_ldo_desc[id],
-						 &config);
+	if (ldo->wm8994->type == WM8994) {
+		ldo->regulator = devm_regulator_register(&pdev->dev,
+							 &wm8994_ldo_desc[id],
+							 &config);
+	} else {
+		ldo->regulator = devm_regulator_register(&pdev->dev,
+							 &wm8958_ldo_desc[id],
+							 &config);
+	}
+
 	if (IS_ERR(ldo->regulator)) {
 		ret = PTR_ERR(ldo->regulator);
 		dev_err(wm8994->dev, "Failed to register LDO%d: %d\n",
-- 
2.20.1