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

Jonathan Cameron
2018-07-21T17:31:17Z

On Tue, 17 Jul 2018 04:41:52 -0400
Brian Masney <masneyb@onstation.org> wrote:

> 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>

I'm not 100% sure what the purpose of the regulator_enabled
tracking is. Perhaps you could point out the path where that is
needed?

Also, a missing bit of documentation needs adding.

Jonathan

> ---
> 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.
Docs missing for regulator_enabled.
> */
> 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*/