regulator: rk808: reduce 'struct rk808' usage

Reduce usage of 'struct rk808' (driver data of the parent MFD), so
that only the chip variant field is still being accessed directly.
This allows restructuring the MFD driver to support SPI based
PMICs.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20221020204251.108565-3-sebastian.reichel@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/rk808-regulator.c

@@ -14,7 +14,6 @@
 
 #include <linux/delay.h>
 #include <linux/gpio.h>
-#include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
@@ -1286,19 +1285,23 @@ dt_parse_end:
 static int rk808_regulator_probe(struct platform_device *pdev)
 {
 	struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
-	struct i2c_client *client = rk808->i2c;
 	struct regulator_config config = {};
 	struct regulator_dev *rk808_rdev;
 	struct rk808_regulator_data *pdata;
 	const struct regulator_desc *regulators;
+	struct regmap *regmap;
 	int ret, i, nregulators;
 
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap)
+		return -ENODEV;
+
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
 
-	ret = rk808_regulator_dt_parse_pdata(&pdev->dev, &client->dev,
-					     rk808->regmap, pdata);
+	ret = rk808_regulator_dt_parse_pdata(&pdev->dev, pdev->dev.parent,
+					     regmap, pdata);
 	if (ret < 0)
 		return ret;
 
@@ -1326,21 +1329,22 @@ static int rk808_regulator_probe(struct platform_device *pdev)
 		nregulators = RK818_NUM_REGULATORS;
 		break;
 	default:
-		dev_err(&client->dev, "unsupported RK8XX ID %lu\n",
+		dev_err(&pdev->dev, "unsupported RK8XX ID %lu\n",
 			rk808->variant);
 		return -EINVAL;
 	}
 
-	config.dev = &client->dev;
+	config.dev = &pdev->dev;
+	config.dev->of_node = pdev->dev.parent->of_node;
 	config.driver_data = pdata;
-	config.regmap = rk808->regmap;
+	config.regmap = regmap;
 
 	/* Instantiate the regulators */
 	for (i = 0; i < nregulators; i++) {
 		rk808_rdev = devm_regulator_register(&pdev->dev,
 						     &regulators[i], &config);
 		if (IS_ERR(rk808_rdev)) {
-			dev_err(&client->dev,
+			dev_err(&pdev->dev,
 				"failed to register %d regulator\n", i);
 			return PTR_ERR(rk808_rdev);
 		}