linux-kernel - [PATCH v3 6/9] regulator: pca9450: Handle hardware with fixed SD

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Message-ID: <20241218152842.97483-7-frieder@fris.de>
Date: Wed, 18 Dec 2024 16:27:29 +0100
From: Frieder Schrempf <frieder@...s.de>
To: linux-arm-kernel@...ts.infradead.org,
	Marek Vasut <marex@...x.de>,
	Conor Dooley <conor@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	linux-kernel@...r.kernel.org,
	Mark Brown <broonie@...nel.org>
Cc: Frieder Schrempf <frieder.schrempf@...tron.de>,
	Bo Liu <liubo03@...pur.com>,
	Frank Li <Frank.Li@....com>,
	Joy Zou <joy.zou@....com>,
	Robin Gong <yibin.gong@....com>
Subject: [PATCH v3 6/9] regulator: pca9450: Handle hardware with fixed SD_VSEL for LDO5

From: Frieder Schrempf <frieder.schrempf@...tron.de>

There are two ways to set the output voltage of the LD05
regulator. First by writing to the voltage selection registers
and second by toggling the SD_VSEL signal.

Usually board designers connect SD_VSEL to the VSELECT signal
controlled by the USDHC controller, but in some cases the
signal is hardwired to a fixed low level (therefore selecting
3.3V as initial value for allowing to boot from the SD card).

In these cases, the voltage is only determined by the value
of the LDO5CTRL_L register. Introduce a property
nxp,sd-vsel-fixed-low to let the driver know that SD_VSEL
is low and there is no GPIO to actually get that
information from dynamically.

Signed-off-by: Frieder Schrempf <frieder.schrempf@...tron.de>
---
Changes for v3:
* Rebase to next-20241218

Changes for v2:
* new patch
---
 drivers/regulator/pca9450-regulator.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/regulator/pca9450-regulator.c b/drivers/regulator/pca9450-regulator.c
index 4519e725706cd..fd40b50318d96 100644
--- a/drivers/regulator/pca9450-regulator.c
+++ b/drivers/regulator/pca9450-regulator.c
@@ -36,6 +36,7 @@ struct pca9450 {
 	enum pca9450_chip_type type;
 	unsigned int rcnt;
 	int irq;
+	bool sd_vsel_fixed_low;
 };
 
 static const struct regmap_range pca9450_status_range = {
@@ -102,6 +103,9 @@ static unsigned int pca9450_ldo5_get_reg_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pca9450 *pca9450 = rdev_get_drvdata(rdev);
 
+	if (pca9450->sd_vsel_fixed_low)
+		return PCA9450_REG_LDO5CTRL_L;
+
 	if (pca9450->sd_vsel_gpio && !gpiod_get_value(pca9450->sd_vsel_gpio))
 		return PCA9450_REG_LDO5CTRL_L;
 
@@ -1112,6 +1116,9 @@ static int pca9450_i2c_probe(struct i2c_client *i2c)
 		return ret;
 	}
 
+	pca9450->sd_vsel_fixed_low =
+		of_property_read_bool(ldo5->dev.of_node, "nxp,sd-vsel-fixed-low");
+
 	dev_info(&i2c->dev, "%s probed.\n",
 		type == PCA9450_TYPE_PCA9450A ? "pca9450a" :
 		(type == PCA9450_TYPE_PCA9451A ? "pca9451a" : "pca9450bc"));
-- 
2.47.1