diff options
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/adc/ina2xx-adc.c | 41 |
1 files changed, 27 insertions, 14 deletions
diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c index 94d506f0f404..144d5c950f2b 100644 --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -705,10 +705,10 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev) /* data buffer needs space for channel data and timestap */ unsigned short data[4 + sizeof(s64)/sizeof(short)]; int bit, ret, i = 0; - s64 time_a, time_b; + s64 time; unsigned int alert; - time_a = iio_get_time_ns(indio_dev); + time = iio_get_time_ns(indio_dev); /* * Because the timer thread and the chip conversion clock @@ -754,11 +754,9 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev) data[i++] = val; } - time_b = iio_get_time_ns(indio_dev); + iio_push_to_buffers_with_timestamp(indio_dev, data, time); - iio_push_to_buffers_with_timestamp(indio_dev, data, time_a); - - return (unsigned long)(time_b - time_a) / 1000; + return 0; }; static int ina2xx_capture_thread(void *data) @@ -766,7 +764,9 @@ static int ina2xx_capture_thread(void *data) struct iio_dev *indio_dev = data; struct ina2xx_chip_info *chip = iio_priv(indio_dev); int sampling_us = SAMPLING_PERIOD(chip); - int buffer_us, delay_us; + int ret; + struct timespec64 next, now, delta; + s64 delay_us; /* * Poll a bit faster than the chip internal Fs, in case @@ -775,15 +775,28 @@ static int ina2xx_capture_thread(void *data) if (!chip->allow_async_readout) sampling_us -= 200; + ktime_get_ts64(&next); + do { - buffer_us = ina2xx_work_buffer(indio_dev); - if (buffer_us < 0) - return buffer_us; + ret = ina2xx_work_buffer(indio_dev); + if (ret < 0) + return ret; - if (sampling_us > buffer_us) { - delay_us = sampling_us - buffer_us; - usleep_range(delay_us, (delay_us * 3) >> 1); - } + ktime_get_ts64(&now); + + /* + * Advance the timestamp for the next poll by one sampling + * interval, and sleep for the remainder (next - now) + * In case "next" has already passed, the interval is added + * multiple times, i.e. samples are dropped. + */ + do { + timespec64_add_ns(&next, 1000 * sampling_us); + delta = timespec64_sub(next, now); + delay_us = div_s64(timespec64_to_ns(&delta), 1000); + } while (delay_us <= 0); + + usleep_range(delay_us, (delay_us * 3) >> 1); } while (!kthread_should_stop()); |