Messages in this thread |  | | Date | Tue, 2 May 2017 19:46:56 +0800 | From | Eva Rachel Retuya <> | Subject | Re: [PATCH v2 2/4] iio: accel: adxl345_core: Introduce set_mode and data_ready functions |
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On Mon, May 01, 2017 at 02:21:02PM +0300, Andy Shevchenko wrote: [...] > Couple of minors below. > Otherwise, FWIW: > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> >
Hello Andy,
> > +static int adxl345_data_ready(struct adxl345_data *data) > > +{ > > + struct device *dev = regmap_get_device(data->regmap); > > > + int tries = 5; > > unsigned int tries = 5; >
Ack.
> > + u32 val; > > + int ret; > > + > > + do { > > > + /* > > + * 1/ODR + 1.1ms; 11.1ms at ODR of 0.10 Hz > > + * Sensor currently operates at default ODR of 100 Hz > > + */ > > + usleep_range(1100, 11100); > > From the above comment I can't get why we sleep first then attempt to > read and not otherwise. Please, elaborate. >
Before this function is called, the sensor is placed into measurement mode. The delay is there to account for the "wake-up" time from standby to measurement mode. So sleep first then attempt to read. In the first version I was not yet aware of it until I look around in the datasheet trying to justify how long to delay. I will clarify the comment to make it more clear.
Thanks, Eva
> > + > > + ret = regmap_read(data->regmap, ADXL345_REG_INT_SOURCE, &val); > > + if (ret < 0) > > + return ret; > > + if ((val & ADXL345_INT_DATA_READY) == ADXL345_INT_DATA_READY) > > + return 0; > > + } while (--tries); > > + dev_err(dev, "Data is not yet ready, try again.\n"); > > + > > + return -EAGAIN; > > +} > > -- > With Best Regards, > Andy Shevchenko
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