On 07/08/14 18:47, Peter Meerwald wrote:
>
>>> Many of the hardware configuration registers may only be modified while the
>>> device is inactive.
>>>
>>> Currently the probe code first activates the device and then modifies the
>>> registers (eg to set the scale). This doesn't actually work but is not
>>> noticed since the scale used is the default value.
>>>
>>> While at it also issue a hardware reset command at probe time.
>>>
>>> Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
>> Looks fine to me but I'd like an OK from Peter for this series.
>
> looks good, no objection, I haven't test yet however
No rush given timing. Just let me know if you aren't going
to test them for a VERY long time ;)
>
> patch 1/8 is a bug fix but not worth for -stable
>
> in patch 2, the local variable ret could be dropped and replaced with
> returns
>
> patch 3, what is the local variable supported_interrupts good for?
>
> patch 6/8 still has wrong subject: io -> iio
>
>>> drivers/iio/accel/mma8452.c | 39 ++++++++++++++++++++++++++++++++++-----
>>> 1 file changed, 34 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>>> index 3c12d49..04a4f34 100644
>>> --- a/drivers/iio/accel/mma8452.c
>>> +++ b/drivers/iio/accel/mma8452.c
>>> @@ -32,6 +32,7 @@
>>> #define MMA8452_OFF_Z 0x31
>>> #define MMA8452_CTRL_REG1 0x2a
>>> #define MMA8452_CTRL_REG2 0x2b
>>> +#define MMA8452_CTRL_REG2_RST BIT(6)
>>>
>>> #define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
>>>
>>> @@ -111,7 +112,7 @@ static const int mma8452_samp_freq[8][2] = {
>>> {6, 250000}, {1, 560000}
>>> };
>>>
>>> -/*
>>> +/*
>> This ought to be in a separate cleanup patch. Just adds noise to the important
>> stuff in here! Not important though so don't bother rerolling the series for this.
>>
>>> * Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048
>>> * The userspace interface uses m/s^2 and we declare micro units
>>> * So scale factor is given by:
>>> @@ -335,6 +336,30 @@ static const struct iio_info mma8452_info = {
>>>
>>> static const unsigned long mma8452_scan_masks[] = {0x7, 0};
>>>
>>> +static int mma8452_reset(struct i2c_client *client)
>>> +{
>>> + int i;
>>> + int ret;
>>> +
>>> + ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG2,
>>> + MMA8452_CTRL_REG2_RST);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + for (i = 0; i < 10; i++) {
>>> + udelay(100);
>>> + ret = i2c_smbus_read_byte_data(client, MMA8452_CTRL_REG2);
>>> + if (ret == -EIO)
>>> + continue; /* I2C comm reset */
>>> + if (ret < 0)
>>> + return ret;
>>> + if (!(ret & MMA8452_CTRL_REG2_RST))
>>> + return 0;
>>> + }
>>> +
>>> + return -ETIMEDOUT;
>>> +}
>>> +
>>> static int mma8452_probe(struct i2c_client *client,
>>> const struct i2c_device_id *id)
>>> {
>>> @@ -365,10 +390,7 @@ static int mma8452_probe(struct i2c_client *client,
>>> indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
>>> indio_dev->available_scan_masks = mma8452_scan_masks;
>>>
>>> - data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
>>> - (MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
>>> - ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
>>> - data->ctrl_reg1);
>>> + ret = mma8452_reset(client);
>>> if (ret < 0)
>>> return ret;
>>>
>>> @@ -378,6 +400,13 @@ static int mma8452_probe(struct i2c_client *client,
>>> if (ret < 0)
>>> return ret;
>>>
>>> + data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
>>> + (MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
>>> + ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
>>> + data->ctrl_reg1);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> ret = iio_triggered_buffer_setup(indio_dev, NULL,
>>> mma8452_trigger_handler, NULL);
>>> if (ret < 0)
>>>
>>> --
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>>>
>>
>
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