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

[Jonathan Cameron]

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

> This patch adds support for the regulator framework to the mpu6050
> driver.
> 
> Signed-off-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
> Signed-off-by: Jonathan Marek <jonathan@xxxxxxxx>

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*/