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Date:   Sat, 5 Jan 2019 17:29:42 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Anson Huang <anson.huang@nxp.com>
Cc:     "knaack.h@gmx.de" <knaack.h@gmx.de>,
        "lars@metafoo.de" <lars@metafoo.de>,
        "pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "martink@posteo.de" <martink@posteo.de>,
        Leonard Crestez <leonard.crestez@nxp.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "gustavo@embeddedor.com" <gustavo@embeddedor.com>,
        "rtresidd@electromag.com.au" <rtresidd@electromag.com.au>,
        "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>
Subject: Re: [PATCH V6 2/2] iio: accell: mma8452: add vdd/vddio regulator
 operation support
Message-ID: <20190105172942.2787d236@archlinux>
In-Reply-To: <1545555462-16121-2-git-send-email-Anson.Huang@nxp.com>
References: <1545555462-16121-1-git-send-email-Anson.Huang@nxp.com>
        <1545555462-16121-2-git-send-email-Anson.Huang@nxp.com>
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On Sun, 23 Dec 2018 09:02:32 +0000
Anson Huang <anson.huang@nxp.com> wrote:

> The accelerometer's power supply could be controllable on some
> platforms, such as i.MX6Q-SABRESD board, the mma8451's power supplies
> are controlled by a GPIO fixed regulator, need to make sure the
> regulators are enabled before any communication with mma8451, this
> patch adds vdd/vddio regulator operation support.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> Acked-by: Martin Kepplinger <martink@posteo.de>

I'm fine with the general approach now, though I would like separate
error handling for the two different regulators.

Also, this has obviously changed a fair bit since Martin originally gave
that Ack.  Martin, could you confirm you are still happy with the code?

Thanks,

Jonathan


> ---
> ChangeLog since V5:
>     - ONLY enable vdd/vddio regulators after both of them are aquired;
>     - Since the suspend/resume operations are same as runtime suspend/resume, so just use the
>       pm_runtime_force_suspend/resume for suspend/resuem callback to simply the code.
> ---
>  drivers/iio/accel/mma8452.c | 99 +++++++++++++++++++++++++++++++++++----------
>  1 file changed, 77 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index 421a0a8..7519ed5 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -31,6 +31,7 @@
>  #include <linux/of_device.h>
>  #include <linux/of_irq.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
>  
>  #define MMA8452_STATUS				0x00
>  #define  MMA8452_STATUS_DRDY			(BIT(2) | BIT(1) | BIT(0))
> @@ -107,6 +108,8 @@ struct mma8452_data {
>  	u8 data_cfg;
>  	const struct mma_chip_info *chip_info;
>  	int sleep_val;
> +	struct regulator *vdd_reg;
> +	struct regulator *vddio_reg;
>  };
>  
>   /**
> @@ -1534,9 +1537,33 @@ static int mma8452_probe(struct i2c_client *client,
>  	mutex_init(&data->lock);
>  	data->chip_info = match->data;
>  
> +	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
> +	data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
> +	if (IS_ERR(data->vdd_reg) || IS_ERR(data->vddio_reg)) {
> +		if (PTR_ERR(data->vdd_reg) == -EPROBE_DEFER ||
> +			PTR_ERR(data->vddio_reg) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +
> +		dev_err(&client->dev, "failed to get VDD/VDDIO regulator!\n");
> +		return IS_ERR(data->vdd_reg) ?
> +		       PTR_ERR(data->vdd_reg) : PTR_ERR(data->vddio_reg);

This is overly complex.  It'll be more lines of code, but I'd prefer
you handle the two separately as the result will be more readable / less
fragile.

> +	}
> +
> +	ret = regulator_enable(data->vdd_reg);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to enable VDD regulator!\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(data->vddio_reg);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
> +		goto disable_regulator_vdd;
> +	}
> +
>  	ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
>  	if (ret < 0)
> -		return ret;
> +		goto disable_regulators;
>  
>  	switch (ret) {
>  	case MMA8451_DEVICE_ID:
> @@ -1549,7 +1576,8 @@ static int mma8452_probe(struct i2c_client *client,
>  			break;
>  		/* else: fall through */
>  	default:
> -		return -ENODEV;
> +		ret = -ENODEV;
> +		goto disable_regulators;
>  	}
>  
>  	dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n",
> @@ -1566,13 +1594,13 @@ static int mma8452_probe(struct i2c_client *client,
>  
>  	ret = mma8452_reset(client);
>  	if (ret < 0)
> -		return ret;
> +		goto disable_regulators;
>  
>  	data->data_cfg = MMA8452_DATA_CFG_FS_2G;
>  	ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
>  					data->data_cfg);
>  	if (ret < 0)
> -		return ret;
> +		goto disable_regulators;
>  
>  	/*
>  	 * By default set transient threshold to max to avoid events if
> @@ -1581,7 +1609,7 @@ static int mma8452_probe(struct i2c_client *client,
>  	ret = i2c_smbus_write_byte_data(client, MMA8452_TRANSIENT_THS,
>  					MMA8452_TRANSIENT_THS_MASK);
>  	if (ret < 0)
> -		return ret;
> +		goto disable_regulators;
>  
>  	if (client->irq) {
>  		int irq2;
> @@ -1595,7 +1623,7 @@ static int mma8452_probe(struct i2c_client *client,
>  						MMA8452_CTRL_REG5,
>  						data->chip_info->all_events);
>  			if (ret < 0)
> -				return ret;
> +				goto disable_regulators;
>  
>  			dev_dbg(&client->dev, "using interrupt line INT1\n");
>  		}
> @@ -1604,11 +1632,11 @@ static int mma8452_probe(struct i2c_client *client,
>  					MMA8452_CTRL_REG4,
>  					data->chip_info->enabled_events);
>  		if (ret < 0)
> -			return ret;
> +			goto disable_regulators;
>  
>  		ret = mma8452_trigger_setup(indio_dev);
>  		if (ret < 0)
> -			return ret;
> +			goto disable_regulators;
>  	}
>  
>  	data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
> @@ -1661,12 +1689,19 @@ static int mma8452_probe(struct i2c_client *client,
>  trigger_cleanup:
>  	mma8452_trigger_cleanup(indio_dev);
>  
> +disable_regulators:
> +	regulator_disable(data->vddio_reg);
> +
> +disable_regulator_vdd:
> +	regulator_disable(data->vdd_reg);
> +
>  	return ret;
>  }
>  
>  static int mma8452_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct mma8452_data *data = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
>  
> @@ -1678,6 +1713,9 @@ static int mma8452_remove(struct i2c_client *client)
>  	mma8452_trigger_cleanup(indio_dev);
>  	mma8452_standby(iio_priv(indio_dev));
>  
> +	regulator_disable(data->vddio_reg);
> +	regulator_disable(data->vdd_reg);
> +
>  	return 0;
>  }
>  
> @@ -1696,6 +1734,18 @@ static int mma8452_runtime_suspend(struct device *dev)
>  		return -EAGAIN;
>  	}
>  
> +	ret = regulator_disable(data->vddio_reg);
> +	if (ret) {
> +		dev_err(dev, "failed to disable VDDIO regulator\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_disable(data->vdd_reg);
> +	if (ret) {
> +		dev_err(dev, "failed to disable VDD regulator\n");
> +		return ret;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -1705,9 +1755,22 @@ static int mma8452_runtime_resume(struct device *dev)
>  	struct mma8452_data *data = iio_priv(indio_dev);
>  	int ret, sleep_val;
>  
> +	ret = regulator_enable(data->vdd_reg);
> +	if (ret) {
> +		dev_err(dev, "failed to enable VDD regulator\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(data->vddio_reg);
> +	if (ret) {
> +		dev_err(dev, "failed to enable VDDIO regulator\n");
> +		regulator_disable(data->vdd_reg);
> +		return ret;
> +	}
> +
>  	ret = mma8452_active(data);
>  	if (ret < 0)
> -		return ret;
> +		goto runtime_resume_failed;
>  
>  	ret = mma8452_get_odr_index(data);
>  	sleep_val = 1000 / mma8452_samp_freq[ret][0];
> @@ -1717,25 +1780,17 @@ static int mma8452_runtime_resume(struct device *dev)
>  		msleep_interruptible(sleep_val);
>  
>  	return 0;
> -}
> -#endif
>  
> -#ifdef CONFIG_PM_SLEEP
> -static int mma8452_suspend(struct device *dev)
> -{
> -	return mma8452_standby(iio_priv(i2c_get_clientdata(
> -		to_i2c_client(dev))));
> -}
> +runtime_resume_failed:
> +	regulator_disable(data->vddio_reg);
> +	regulator_disable(data->vdd_reg);
>  
> -static int mma8452_resume(struct device *dev)
> -{
> -	return mma8452_active(iio_priv(i2c_get_clientdata(
> -		to_i2c_client(dev))));
> +	return ret;
>  }
>  #endif
>  
>  static const struct dev_pm_ops mma8452_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(mma8452_suspend, mma8452_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
>  	SET_RUNTIME_PM_OPS(mma8452_runtime_suspend,
>  			   mma8452_runtime_resume, NULL)
>  };