regulator: pca9450: Make I2C Level Translator configurable

Make the I2C Level Translator included in PCA9450 configurable from
devicetree. The reset state is off. By setting nxp,i2c-lt-enable, the
I2C Level Translator will be enabled while in STANDBY or RUN state.

Signed-off-by: Per-Daniel Olsson <perdo@axis.com>
Signed-off-by: Rickard x Andersson <rickaran@axis.com>
Link: https://lore.kernel.org/r/20220429072211.24957-2-rickaran@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Per-Daniel Olsson

drivers/regulator/pca9450-regulator.c

@@ -810,6 +810,17 @@ static int pca9450_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	if (of_property_read_bool(i2c->dev.of_node, "nxp,i2c-lt-enable")) {
+		/* Enable I2C Level Translator */
+		ret = regmap_update_bits(pca9450->regmap, PCA9450_REG_CONFIG2,
+					 I2C_LT_MASK, I2C_LT_ON_STANDBY_RUN);
+		if (ret) {
+			dev_err(&i2c->dev,
+				"Failed to enable I2C level translator\n");
+			return ret;
+		}
+	}
+
 	/*
 	 * The driver uses the LDO5CTRL_H register to control the LDO5 regulator.
 	 * This is only valid if the SD_VSEL input of the PMIC is high. Let's

include/linux/regulator/pca9450.h

@@ -226,4 +226,11 @@ enum {
 #define WDOG_B_CFG_COLD_LDO12		0x80
 #define WDOG_B_CFG_COLD			0xC0
 
+/* PCA9450_REG_CONFIG2 bits */
+#define I2C_LT_MASK			0x03
+#define I2C_LT_FORCE_DISABLE		0x00
+#define I2C_LT_ON_STANDBY_RUN		0x01
+#define I2C_LT_ON_RUN			0x02
+#define I2C_LT_FORCE_ENABLE		0x03
+
 #endif /* __LINUX_REG_PCA9450_H__ */