Re: [PATCH v2 3/3] iio: adc: Fix polling of INA219 conversion ready flag

Jonathan Cameron
2017-05-24T19:53:42Z

On Wed, 24 May 2017 02:09:07 +0200
Stefan Brüns <stefan.bruens@rwth-aachen.de> wrote:

> While the INA226 has a conversion ready flag (CVRF) in the R/W Mask/Enable
> register with read-to-clear semantics, the corresponding bit of the INA219
> (CNVR) is part of the bus voltage register. The flag is cleared by reading
> the power register.
>
> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Again, looks good to me, but I would like input form Marc or Andrew
who are more familiar with these devices than me!

Ping me in a week or two if nothing is happening and I look to have
lost these!

Thanks,

Jonathan
> ---
> drivers/iio/adc/ina2xx-adc.c | 36 +++++++++++++++++++++++++++++-------
> 1 file changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> index 232c0b80d658..68884d26b50c 100644
> --- a/drivers/iio/adc/ina2xx-adc.c
> +++ b/drivers/iio/adc/ina2xx-adc.c
> @@ -44,6 +44,7 @@
>
> #define INA226_MASK_ENABLE 0x06
> #define INA226_CVRF BIT(3)
> +#define INA219_CNVR BIT(1)
>
> #define INA2XX_MAX_REGISTERS 8
>
> @@ -592,6 +593,7 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev)
> int bit, ret, i = 0;
> s64 time_a, time_b;
> unsigned int alert;
> + int cnvr_need_clear = 0;
>
> time_a = iio_get_time_ns(indio_dev);
>
> @@ -603,22 +605,30 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev)
> * we check the ConVersionReadyFlag.
> * On hardware that supports using the ALERT pin to toggle a
> * GPIO a triggered buffer could be used instead.
> - * For now, we pay for that extra read of the ALERT register
> + * For now, we do an extra read of the MASK_ENABLE register (INA226)
> + * resp. the BUS_VOLTAGE register (INA219).
> */
> if (!chip->allow_async_readout)
> do {
> - ret = regmap_read(chip->regmap, INA226_MASK_ENABLE,
> - &alert);
> + if (chip->config->chip_id == ina226) {
> + ret = regmap_read(chip->regmap,
> + INA226_MASK_ENABLE, &alert);
> + alert &= INA226_CVRF;
> + } else {
> + ret = regmap_read(chip->regmap,
> + INA2XX_BUS_VOLTAGE, &alert);
> + alert &= INA219_CNVR;
> + cnvr_need_clear = alert;
> + }
> +
> if (ret < 0)
> return ret;
>
> - alert &= INA226_CVRF;
> } while (!alert);
>
> /*
> - * Single register reads: bulk_read will not work with ina226
> - * as there is no auto-increment of the address register for
> - * data length longer than 16bits.
> + * Single register reads: bulk_read will not work with ina226/219
> + * as there is no auto-increment of the register pointer.
> */
> for_each_set_bit(bit, indio_dev->active_scan_mask,
> indio_dev->masklength) {
> @@ -630,6 +640,18 @@ static int ina2xx_work_buffer(struct iio_dev *indio_dev)
> return ret;
>
> data[i++] = val;
> +
> + if (INA2XX_SHUNT_VOLTAGE + bit == INA2XX_POWER)
> + cnvr_need_clear = 0;
> + }
> +
> + /* Dummy read on INA219 power register to clear CNVR flag */
> + if (cnvr_need_clear && chip->config->chip_id == ina219) {
> + unsigned int val;
> +
> + ret = regmap_read(chip->regmap, INA2XX_POWER, &val);
> + if (ret < 0)
> + return ret;
> }
>
> time_b = iio_get_time_ns(indio_dev);