Re: [PATCH v2] iio: accell: mma8452: Reduce sleep time when data not ready

[Martin Kepplinger <martink@posteo.de>]

On 2018-05-07 09:59, Richard Tresidder wrote:
> Hi Martin
>     Thanks, I'll remove that /*FALLTHRU*/ compiler "disable warning" comment > I assume it is the correct comment to use to shut the compiler up?

Please use /* fallthrough */ instead.

> I've also fixed up a couple of whitespace issues that checkpatch pulled me up on.
> Hard to know when to merge something or not.. seen that one merged in a few times in logs..

just like the fallthrough marker, make it a follow-up patch to your 
change (the sleep fix).

> 
> Regards
>     Richard
> 
> On 7/05/2018 3:49 PM, Martin Kepplinger wrote:
> 
>> On 2018-05-07 06:13, Richard Tresidder wrote:
>>> Modified the sleep method when data is not ready to allow for sampling > 50sps to work.
>>> Fix Fallthru warning in case statement
>>> Signed-off-by: Richard Tresidder <rtresidd@electromag.com.au>
>>> --
>>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>>> index 7a2da7f..948740d 100644
>>> --- a/drivers/iio/accel/mma8452.c
>>> +++ b/drivers/iio/accel/mma8452.c
>>> @@ -106,6 +106,7 @@ struct mma8452_data {
>>>        u8 ctrl_reg1;
>>>        u8 data_cfg;
>>>        const struct mma_chip_info *chip_info;
>>> +    int sleep_val;
>>>    };
>>>    
>>>     /**
>>> @@ -193,7 +194,10 @@ static int mma8452_drdy(struct mma8452_data *data)
>>>            if ((ret & MMA8452_STATUS_DRDY) == MMA8452_STATUS_DRDY)
>>>                return 0;
>>>    
>>> -        msleep(20);
>>> +        if (data->sleep_val <= 20)
>>> +            usleep_range(data->sleep_val * 250, data->sleep_val * 500);
>>> +        else
>>> +            msleep(20);
>>>        }
>>>    
>>>        dev_err(&data->client->dev, "data not ready\n");
>>> @@ -544,6 +548,18 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
>>>        return -EINVAL;
>>>    }
>>>    
>>> +static int mma8452_calculate_sleep(struct mma8452_data *data)
>>> +{
>>> +    int ret, i = mma8452_get_odr_index(data);
>>> +
>>> +    if (mma8452_samp_freq[i][0] > 0)
>>> +        ret = 1000 / mma8452_samp_freq[i][0];
>>> +    else
>>> +        ret = 1000;
>>> +
>>> +    return ret == 0 ? 1 : ret;
>>> +}
>>> +
>>>    static int mma8452_standby(struct mma8452_data *data)
>>>    {
>>>        return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
>>> @@ -700,6 +716,8 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
>>>            data->ctrl_reg1 &= ~MMA8452_CTRL_DR_MASK;
>>>            data->ctrl_reg1 |= i << MMA8452_CTRL_DR_SHIFT;
>>>    
>>> +        data->sleep_val = mma8452_calculate_sleep(data);
>>> +
>>>            ret = mma8452_change_config(data, MMA8452_CTRL_REG1,
>>>                            data->ctrl_reg1);
>>>            break;
>>> @@ -1528,6 +1546,7 @@ static int mma8452_probe(struct i2c_client *client,
>>>        case FXLS8471_DEVICE_ID:
>>>            if (ret == data->chip_info->chip_id)
>>>                break;
>>> +        /* FALLTHRU */
>> Please do this in a seperate patch.
>>>        default:
>>>            return -ENODEV;
>>>        }
>>> @@ -1593,6 +1612,9 @@ static int mma8452_probe(struct i2c_client *client,
>>>    
>>>        data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
>>>                  (MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
>>> +
>>> +    data->sleep_val = mma8452_calculate_sleep(data);
>>> +
>>>        ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
>>>                        data->ctrl_reg1);
>>>        if (ret < 0)
>> --
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