[PATCH v2 1/7] iio: imu: mpu6050: add support for regulator framework

Brian Masney
2018-07-17T08:42:08Z

This patch adds support for the regulator framework to the mpu6050
driver.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
---
Changes since v1:
- Use devm_regulator_get() instead of devm_regulator_get_optional()
- Use devm_add_action() for cleaning up the regulator.
- Correct ordering of resume code.
- Add regulator_enabled flag to ensure regulator is not disabled twice,
specifically the case where the device is suspended and then the
driver is removed.

Original extra changelog from v1:

This is a variation of Jonathan Marek's patch from postmarketOS
https://gitlab.com/postmarketOS/linux-postmarketos/commit/b8ad1ec1859c8bbcbce94944b3f4dd68f8f9fc37
with the following changes:

- Stripped out 6515 variant code.
- Add the regulator to the mpu core instead of only the i2c variant.
- Add error handling.
- Release the regulator on suspend, device remove, etc.
- Device tree documentation.

.../bindings/iio/imu/inv_mpu6050.txt | 1 +
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 73 +++++++++++++++++++
drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 3 +
3 files changed, 77 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt b/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
index b7def51c8ad9..d39907b12a46 100644
--- a/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
+++ b/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
@@ -21,6 +21,7 @@ Required properties:
bindings.

Optional properties:
+ - vddio-supply: regulator phandle for VDDIO supply
- mount-matrix: an optional 3x3 mounting rotation matrix
- i2c-gate node. These devices also support an auxiliary i2c bus. This is
simple enough to be described using the i2c-gate binding. See
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 12c1b9507007..e1fbab4bc0a0 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -23,6 +23,7 @@
#include <linux/iio/iio.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
#include "inv_mpu_iio.h"

/*
@@ -926,6 +927,46 @@ static int inv_check_and_setup_chip(struct inv_mpu6050_state *st)
return result;
}

+static int inv_mpu_core_enable_regulator(struct inv_mpu6050_state *st)
+{
+ int result;
+
+ result = regulator_enable(st->vddio_supply);
+ if (result) {
+ dev_err(regmap_get_device(st->map),
+ "Failed to enable regulator: %d\n", result);
+ } else {
+ st->regulator_enabled = true;
+
+ /* Give the device a little bit of time to start up. */
+ usleep_range(35000, 70000);
+ }
+
+ return result;
+}
+
+static int inv_mpu_core_disable_regulator(struct inv_mpu6050_state *st)
+{
+ int result;
+
+ if (!st->regulator_enabled)
+ return 0;
+
+ result = regulator_disable(st->vddio_supply);
+ if (result)
+ dev_err(regmap_get_device(st->map),
+ "Failed to disable regulator: %d\n", result);
+
+ st->regulator_enabled = false;
+
+ return result;
+}
+
+static void inv_mpu_core_disable_regulator_action(void *_data)
+{
+ inv_mpu_core_disable_regulator(_data);
+}
+
int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
int (*inv_mpu_bus_setup)(struct iio_dev *), int chip_type)
{
@@ -990,6 +1031,28 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
return -EINVAL;
}

+ st->vddio_supply = devm_regulator_get(dev, "vddio");
+ if (IS_ERR(st->vddio_supply)) {
+ if (PTR_ERR(st->vddio_supply) != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get vddio regulator %d\n",
+ (int)PTR_ERR(st->vddio_supply));
+
+ return PTR_ERR(st->vddio_supply);
+ }
+
+ result = inv_mpu_core_enable_regulator(st);
+ if (result)
+ return result;
+
+ result = devm_add_action(dev, inv_mpu_core_disable_regulator_action,
+ st);
+ if (result) {
+ inv_mpu_core_disable_regulator_action(st);
+ dev_err(dev, "Failed to setup regulator cleanup action %d\n",
+ result);
+ return result;
+ }
+
/* power is turned on inside check chip type*/
result = inv_check_and_setup_chip(st);
if (result)
@@ -1049,7 +1112,12 @@ static int inv_mpu_resume(struct device *dev)
int result;

mutex_lock(&st->lock);
+ result = inv_mpu_core_enable_regulator(st);
+ if (result)
+ goto out_unlock;
+
result = inv_mpu6050_set_power_itg(st, true);
+out_unlock:
mutex_unlock(&st->lock);

return result;
@@ -1062,6 +1130,11 @@ static int inv_mpu_suspend(struct device *dev)

mutex_lock(&st->lock);
result = inv_mpu6050_set_power_itg(st, false);
+ if (result)
+ goto out_unlock;
+
+ result = inv_mpu_core_disable_regulator(st);
+out_unlock:
mutex_unlock(&st->lock);

return result;
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index e69a59659dbc..01c8fe9b4fa0 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -129,6 +129,7 @@ struct inv_mpu6050_hw {
* @chip_period: chip internal period estimation (~1kHz).
* @it_timestamp: timestamp from previous interrupt.
* @data_timestamp: timestamp for next data sample.
+ * @vddio_supply voltage regulator for the chip.
*/
struct inv_mpu6050_state {
struct mutex lock;
@@ -149,6 +150,8 @@ struct inv_mpu6050_state {
s64 chip_period;
s64 it_timestamp;
s64 data_timestamp;
+ struct regulator *vddio_supply;
+ bool regulator_enabled;
};

/*register and associated bit definition*/
--
2.17.1