On 2017-05-08 10:25, Andy Shevchenko wrote:
> On Mon, May 8, 2017 at 10:49 AM, Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote:
>> This is an upstream port of an IIO driver for the TI ADC108S102 and
>> ADC128S102. The former can be found on the Intel Galileo Gen2 and the
>> Siemens SIMATIC IOT2000. For those boards, ACPI-based enumeration is
>> included.
>>
>> Due to the lack of regulators under ACPI, we hard-code the voltage
>> provided to the VA pin of the ADC to 5 V, the value used on Galileo and
>> IOT2000. For DT usage, the regulator "vref-supply" provides this
>> information. Note that DT usage has not been tested.
>>
>> Original author: Bogdan Pricop <bogdan.pricop@xxxxxxxxxx>
>> Ported from Intel Galileo Gen2 BSP to Intel Yocto kernel:
>> Todor Minchev <todor@xxxxxxxxxxxxx>.
>>
>
>> +static int adc108s102_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan,
>> + int *val, int *val2, long m)
>> +{
>> + struct adc108s102_state *st = iio_priv(indio_dev);
>> + int ret;
>> +
>> + switch (m) {
>> + case IIO_CHAN_INFO_RAW:
>> + ret = iio_device_claim_direct_mode(indio_dev);
>> + if (ret)
>> + return ret;
>> +
>> + ret = adc108s102_scan_direct(st, chan->address);
>> +
>> + iio_device_release_direct_mode(indio_dev);
>> +
>> + if (ret < 0)
>> + return ret;
>> +
>> + *val = ADC108S102_RES_DATA(ret);
>> +
>> + return IIO_VAL_INT;
>> + case IIO_CHAN_INFO_SCALE:
>> + if (chan->type == IIO_VOLTAGE) {
>> + *val = st->va_millivolt;
>> + *val2 = chan->scan_type.realbits;
>> + return IIO_VAL_FRACTIONAL_LOG2;
>
>> + } else {
>
> Redundant. and I would rather go with pattern
>
> if (chan->type != IIO_VOLTAGE)
> return -EINVAL;
>
> ...
> return IIO_VAL_FRACTIONAL_LOG2;
>
> _Or_ use
>
> break;
>
> here
>
>> + return -EINVAL;
>> + }
>> + default:
>> + return -EINVAL;
>
> ...and here.
>
>> + }
>
> ...and
>
> return -EINVAL;
>
> in one place.
OK.
>
>> +}
>
>> + if (ACPI_COMPANION(&spi->dev)) {
>> + st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;
>> + } else {
>
>> + st->reg = devm_regulator_get(&spi->dev, "vref");
>
> I'm still not satisfied with this. Why we just can't use _optional()
> unconditionally?
Because - again - the regulator is NOT optional under DT.
> If regulator framework is broken it should be fixed first then.
>
>> + if (IS_ERR(st->reg))
>> + return PTR_ERR(st->reg);
>> +
>> + ret = regulator_enable(st->reg);
>> + if (ret < 0) {
>> + dev_err(&spi->dev, "Cannot enable vref regulator\n");
>> + return ret;
>> + }
>> +
>> + ret = regulator_get_voltage(st->reg);
>> + if (ret < 0) {
>> + dev_err(&spi->dev, "vref get voltage failed\n");
>> + return ret;
>> + }
>> +
>> + st->va_millivolt = ret / 1000;
>> + }
>
>> + if (!IS_ERR(st->reg))
>
> I'm wondering why regulator framework does need this check.
Forgotten artifact from previous version, sorry. st->reg is now either
valid or NULL, and both cases are fine for disable.
Jan
>
>> + regulator_disable(st->reg);
>
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
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