[PATCH 04/10 v4] iio: pressure: bmp280: support supply regulators

[Linus Walleij <linus.walleij@linaro.org>]

The BMP085/BMP180/BMP280 is supplied with two power sources:
VDDA (analog power) and VDDD (digital power). As these may come
from regulators (as on the APQ8060 Dragonboard) we need the driver
to attempt to fetch and enable these regulators.

We FAIL if we cannot: boards should either define:
- Proper regulators if present
- Define fixed regulators if power is hardwired to the component
- Rely on dummy regulators (will be present on all DT systems and
  any boardfile system that calls regulator_has_full_constraints().

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v3->v4:
- Fix missing "regulator" string in enablement message.
- Fix BMP058->BMP085 in commit message
ChangeLog v2->v3:
- Encode a start-up time for each sensor type (from the datasheets)
  this is necessary when coldstarting the sensor with a regulator
  to be sure it is on before we try to use it.
- Introduce a try/catch-style set of goto clauses in the probe
  function to make sure the regulators are properly disabled.
ChangeLog v1->v2:
- Make the regulators non-optional: an optional supply is one you
  can choose not to supply ELECTRICALLY as in an internal charge
  pump taking its place or so.
- Bail out if not present and add some notices to the commit that
  boards need to think about their regulator usage.
- Make sure we disable the regulators, and introduce a .remove()
  call to do that if/when the module is removed.
---
 drivers/iio/pressure/bmp280.c | 64 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c
index 1618968f8889..5245bc598187 100644
--- a/drivers/iio/pressure/bmp280.c
+++ b/drivers/iio/pressure/bmp280.c
@@ -24,6 +24,7 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
 
 /* BMP280 specific registers */
 #define BMP280_REG_HUMIDITY_LSB		0xFE
@@ -124,6 +125,9 @@ struct bmp280_data {
 	struct mutex lock;
 	struct regmap *regmap;
 	const struct bmp280_chip_info *chip_info;
+	struct regulator *vddd;
+	struct regulator *vdda;
+	unsigned int start_up_time; /* in milliseconds */
 
 	/* log of base 2 of oversampling rate */
 	u8 oversampling_press;
@@ -1047,12 +1051,14 @@ static int bmp280_probe(struct i2c_client *client,
 		data->chip_info = &bmp180_chip_info;
 		data->oversampling_press = ilog2(8);
 		data->oversampling_temp = ilog2(1);
+		data->start_up_time = 10;
 		break;
 	case BMP280_CHIP_ID:
 		indio_dev->num_channels = 2;
 		data->chip_info = &bmp280_chip_info;
 		data->oversampling_press = ilog2(16);
 		data->oversampling_temp = ilog2(2);
+		data->start_up_time = 2;
 		break;
 	case BME280_CHIP_ID:
 		indio_dev->num_channels = 3;
@@ -1060,11 +1066,37 @@ static int bmp280_probe(struct i2c_client *client,
 		data->oversampling_press = ilog2(16);
 		data->oversampling_humid = ilog2(16);
 		data->oversampling_temp = ilog2(2);
+		data->start_up_time = 2;
 		break;
 	default:
 		return -EINVAL;
 	}
 
+	/* Bring up regulators */
+	data->vddd = devm_regulator_get(&client->dev, "vddd");
+	if (IS_ERR(data->vddd)) {
+		dev_err(&client->dev, "failed to get VDDD regulator\n");
+		return PTR_ERR(data->vddd);
+	}
+	ret = regulator_enable(data->vddd);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable VDDD regulator\n");
+		return ret;
+	}
+	data->vdda = devm_regulator_get(&client->dev, "vdda");
+	if (IS_ERR(data->vdda)) {
+		dev_err(&client->dev, "failed to get VDDA regulator\n");
+		ret = PTR_ERR(data->vddd);
+		goto out_disable_vddd;
+	}
+	ret = regulator_enable(data->vdda);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable VDDA regulator\n");
+		goto out_disable_vddd;
+	}
+	/* Wait to make sure we started up properly */
+	mdelay(data->start_up_time);
+
 	/* Bring chip out of reset if there is an assigned GPIO line */
 	gpiod = devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_HIGH);
 	/* Deassert the signal */
@@ -1077,7 +1109,8 @@ static int bmp280_probe(struct i2c_client *client,
 					data->chip_info->regmap_config);
 	if (IS_ERR(data->regmap)) {
 		dev_err(&client->dev, "failed to allocate register map\n");
-		return PTR_ERR(data->regmap);
+		ret = PTR_ERR(data->regmap);
+		goto out_disable_vdda;
 	}
 
 	ret = regmap_read(data->regmap, BMP280_REG_ID, &chip_id);
@@ -1086,14 +1119,36 @@ static int bmp280_probe(struct i2c_client *client,
 	if (chip_id != id->driver_data) {
 		dev_err(&client->dev, "bad chip id.  expected %x got %x\n",
 			BMP280_CHIP_ID, chip_id);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out_disable_vdda;
 	}
 
 	ret = data->chip_info->chip_config(data);
 	if (ret < 0)
-		return ret;
+		goto out_disable_vdda;
+
+	i2c_set_clientdata(client, data);
 
-	return devm_iio_device_register(&client->dev, indio_dev);
+	ret = devm_iio_device_register(&client->dev, indio_dev);
+	if (ret)
+		goto out_disable_vdda;
+
+	return 0;
+
+out_disable_vdda:
+	regulator_disable(data->vdda);
+out_disable_vddd:
+	regulator_disable(data->vddd);
+	return ret;
+}
+
+static int bmp280_remove(struct i2c_client *client)
+{
+	struct bmp280_data *data = i2c_get_clientdata(client);
+
+	regulator_disable(data->vdda);
+	regulator_disable(data->vddd);
+	return 0;
 }
 
 static const struct acpi_device_id bmp280_acpi_match[] = {
@@ -1134,6 +1189,7 @@ static struct i2c_driver bmp280_driver = {
 		.of_match_table = of_match_ptr(bmp280_of_match),
 	},
 	.probe		= bmp280_probe,
+	.remove		= bmp280_remove,
 	.id_table	= bmp280_id,
 };
 module_i2c_driver(bmp280_driver);
-- 
2.4.11