Re: [PATCH V7 2/2] iio: accell: mma8452: add vdd/vddio regulator operation support

[Anson Huang <anson.huang@nxp.com>]

Hi, Martin

From Anson's iPhone 6


> 在 2019年1月8日，19:41，Martin Kepplinger <martink@posteo.de> 写道：
> 
>> On 08.01.19 10:14, Anson Huang 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>
>> ---
>> ChangeLog Since V6:
>>  - separate the error handling of regulators get to make code easy to read.
>> ---
>> drivers/iio/accel/mma8452.c | 105 ++++++++++++++++++++++++++++++++++----------
>> 1 file changed, 83 insertions(+), 22 deletions(-)
>> 
>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>> index 421a0a8..3027811 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 +1537,39 @@ 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");
>> +    if (IS_ERR(data->vdd_reg)) {
>> +        if (PTR_ERR(data->vdd_reg) == -EPROBE_DEFER)
>> +            return -EPROBE_DEFER;
>> +
>> +        dev_err(&client->dev, "failed to get VDD regulator!\n");
>> +        return PTR_ERR(data->vdd_reg);
>> +    }
>> +
>> +    data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
>> +    if (IS_ERR(data->vddio_reg)) {
>> +        if (PTR_ERR(data->vddio_reg) == -EPROBE_DEFER)
>> +            return -EPROBE_DEFER;
>> +
>> +        dev_err(&client->dev, "failed to get VDDIO regulator!\n");
>> +        return PTR_ERR(data->vddio_reg);
>> +    }
>> +
>> +    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 +1582,8 @@ 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 +1600,13 @@ 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 +1615,7 @@ 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 +1629,7 @@ 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 +1638,11 @@ 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 +1695,19 @@ 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 +1719,9 @@ 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 +1740,18 @@ 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 +1761,22 @@ 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 +1786,17 @@ 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)
> 
> Just a quesion: Isn't it semantically a different change to replace
> mma8452_suspend() and mma8452_resume()? If not, why is it needed here?
> 
> other than that, lgtm.

It is because with regulator operation added, before system suspend, driver is in runtime suspend already, the suspend/resume callback need to deal with regulator again including error handling etc., and also need to disable runtime pm and re-enable it etc., this introduces too many complicated code/logic, also, the things suspend/resume callback does are actually same as runtime suspend/ resume, so just using pm_runtime_force_suspend/resume can save these duplicated operations and make code easy/clean.

Anson.




> 
>>    SET_RUNTIME_PM_OPS(mma8452_runtime_suspend,
>>               mma8452_runtime_resume, NULL)
>> };
>> 
>