RE: [PATCH v4] iio: adc: Add TI ADS1015 ADC driver support

[Sricharan]

Hi,

> -----Original Message-----
> From: Michael Welling [mailto:mwelling79@xxxxxxxxx] On Behalf Of Michael
> Welling
> Sent: Monday, February 08, 2016 10:07 PM
> To: Wolfram Sang
> Cc: Daniel Baluta; Jonathan Cameron; Hartmut Knaack; Lars-Peter Clausen;
> Peter Meerwald-Stadler; Linux Kernel Mailing List;
linux-iio@xxxxxxxxxxxxxxx;
> Lucas De Marchi; Andy Gross; Pramod Gurav; Bjorn Andersson; Guenter
> Roeck; eibach@xxxxxxxx; Sricharan R; linux-arm-msm@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4] iio: adc: Add TI ADS1015 ADC driver support
> 
> On Mon, Feb 08, 2016 at 11:25:00AM +0100, Wolfram Sang wrote:
> > On Fri, Feb 05, 2016 at 06:32:45PM -0600, Michael Welling wrote:
> > > On Fri, Feb 05, 2016 at 09:32:34PM +0200, Daniel Baluta wrote:
> > > > >> +static int ads1015_read_raw(struct iio_dev *indio_dev,
> > > > >> +                         struct iio_chan_spec const *chan, int
*val,
> > > > >> +                         int *val2, long mask) {
> > > > >> +     int ret, idx;
> > > > >> +     struct ads1015_data *data = iio_priv(indio_dev);
> > > > >> +
> > > > >> +     mutex_lock(&data->lock);
> > > > >> +     switch (mask) {
> > > > >> +     case IIO_CHAN_INFO_RAW:
> > > > >> +             if (iio_buffer_enabled(indio_dev)) {
> > > > >> +                     ret = -EBUSY;
> > > > >> +                     break;
> > > > >> +             }
> > > > >> +
> > > > >> +             ret = ads1015_set_power_state(data, true);
> > > > >> +             if (ret < 0)
> > > > >> +                     break;
> > > > >
> > > > > Just tested the driver on a Dragonboard 410C with a robotics
> > > > > mezzanine that I designed.
> > > > >
> > > > > The above ads1015_set_power_state(data, true) is always returning
-
> EINVAL.
> > > > >
> > > > > Any ideas why that would be happening?
> > > > > I think it may be the return from pm_runtime_get_sync?
> > > >
> > > > Can you confirm that pm_runtime_get_sync fails? Using some printk?
> > > >
> > > > Also adding printks in suspend/resume function would be helpful.
> > > > Do you have CONFIG_PM enabled?
> > > >
> > >
> > > Indeed it is the pm_runtime_get_sync that fails with a -EINVAL.
> > >
> > > > >
> > > > > When I comment out the break the readings come back but are not
> updated continually.
> > > > > If I read in_voltage0-voltage1_raw then in_voltage0_raw the value
is
> updated.
> > > >
> > > > I guess this is normal if set_power_state fails.
> > >
> > > The hwmod driver works fine BTW.
> > >
> > > My guess is there is an issue with the qup i2c driver seeing as it
> > > has worked on other system without issue.
> > >
> > > CC'd some the latest developer on the qup i2c driver.
> > >
> > > I2C guys have any ideas on this?
> > >
> >
> > Adding some more people who recently worked on this. Might be nice to
> > know which kernel version you are using.
> >
 Which i2c bus is this connected to ? I can give a try with 410c to see why
pm_runtime_get_sync from qup
 fails.

Regards,
  Sricharan