Re: [PATCH v5 01/11] staging: iio: ad7780: add gain & filter gpio support

Jonathan Cameron
2019-03-16T17:46:54Z

On Fri, 15 Mar 2019 23:12:27 -0300
Renato Lui Geh <renatogeh@gmail.com> wrote:

> Previously, the AD7780 driver only supported gpio for the 'powerdown'
> pin. This commit adds suppport for the 'gain' and 'filter' pin.
>
> Signed-off-by: Renato Lui Geh <renatogeh@gmail.com>
> Signed-off-by: Giuliano Belinassi <giuliano.belinassi@usp.br>
> Co-developed-by: Giuliano Belinassi <giuliano.belinassi@usp.br>
Something a little odd happened when trying to use git am on this,
but patch was happy so I did it that way. Please give it a quick
sanity check once I push the tree out incase we have a real problem.

Applied to the togreg branch of iio.git to be shortly pushed out
as testing for the autobuilders to play with it.

Thanks,

Jonathan

> ---
> Changes in v3:
> - Renamed ad7780_chip_info's filter to odr
> - Renamed ad778x_filter to ad778x_odr_avail
> - Changed vref variable from unsigned int to unsigned long long to avoid
> overflow
> - Removed unnecessary AD_SD_CHANNEL macro
> Changes in v4:
> - Removed useless macro
> - Added default case for switch to suppress warning
> - Removed chunks belonging to filter reading, adding these as a
> patch for itself
> Changes in v5:
> - ad778x_odr_avail moved to filter patch
> - Split gain reading to its own patch
> - Init GPIOs in a separate function
>
> drivers/staging/iio/adc/ad7780.c | 114 ++++++++++++++++++++++++++-----
> 1 file changed, 96 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
> index c4a85789c2db..07e5e35c92a3 100644
> --- a/drivers/staging/iio/adc/ad7780.c
> +++ b/drivers/staging/iio/adc/ad7780.c
> @@ -39,6 +39,9 @@
> #define AD7170_PATTERN (AD7780_PAT0 | AD7170_PAT2)
> #define AD7170_PATTERN_MASK (AD7780_PAT0 | AD7780_PAT1 | AD7170_PAT2)
>
> +#define AD7780_GAIN_MIDPOINT 64
> +#define AD7780_FILTER_MIDPOINT 13350
> +
> struct ad7780_chip_info {
> struct iio_chan_spec channel;
> unsigned int pattern_mask;
> @@ -50,7 +53,10 @@ struct ad7780_state {
> const struct ad7780_chip_info *chip_info;
> struct regulator *reg;
> struct gpio_desc *powerdown_gpio;
> - unsigned int gain;
> + struct gpio_desc *gain_gpio;
> + struct gpio_desc *filter_gpio;
> + unsigned int gain;
> + unsigned int int_vref_mv;
>
> struct ad_sigma_delta sd;
> };
> @@ -104,8 +110,10 @@ static int ad7780_read_raw(struct iio_dev *indio_dev,
> voltage_uv = regulator_get_voltage(st->reg);
> if (voltage_uv < 0)
> return voltage_uv;
> - *val = (voltage_uv / 1000) * st->gain;
> + voltage_uv /= 1000;
> + *val = voltage_uv * st->gain;
> *val2 = chan->scan_type.realbits - 1;
> + st->int_vref_mv = voltage_uv;
> return IIO_VAL_FRACTIONAL_LOG2;
> case IIO_CHAN_INFO_OFFSET:
> *val = -(1 << (chan->scan_type.realbits - 1));
> @@ -115,6 +123,50 @@ static int ad7780_read_raw(struct iio_dev *indio_dev,
> return -EINVAL;
> }
>
> +static int ad7780_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val,
> + int val2,
> + long m)
> +{
> + struct ad7780_state *st = iio_priv(indio_dev);
> + const struct ad7780_chip_info *chip_info = st->chip_info;
> + unsigned long long vref;
> + unsigned int full_scale, gain;
> +
> + if (!chip_info->is_ad778x)
> + return -EINVAL;
> +
> + switch (m) {
> + case IIO_CHAN_INFO_SCALE:
> + if (val != 0)
> + return -EINVAL;
> +
> + vref = st->int_vref_mv * 1000000LL;
> + full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
> + gain = DIV_ROUND_CLOSEST(vref, full_scale);
> + gain = DIV_ROUND_CLOSEST(gain, val2);
> + st->gain = gain;
> + if (gain < AD7780_GAIN_MIDPOINT)
> + gain = 0;
> + else
> + gain = 1;
> + gpiod_set_value(st->gain_gpio, gain);
> + break;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
> + val = 0;
> + else
> + val = 1;
> + gpiod_set_value(st->filter_gpio, val);
> + break;
> + default:
> + break;
> + }
> +
> + return 0;
> +}
> +
> static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
> unsigned int raw_sample)
> {
> @@ -125,13 +177,6 @@ static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
> ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
> return -EIO;
>
> - if (chip_info->is_ad778x) {
> - if (raw_sample & AD7780_GAIN)
> - st->gain = 1;
> - else
> - st->gain = 128;
> - }
> -
> return 0;
> }
>
> @@ -173,8 +218,47 @@ static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
>
> static const struct iio_info ad7780_info = {
> .read_raw = ad7780_read_raw,
> + .write_raw = ad7780_write_raw,
> };
>
> +static int ad7780_init_gpios(struct device *dev, struct ad7780_state *st)
> +{
> + int ret;
> +
> + st->powerdown_gpio = devm_gpiod_get_optional(dev,
> + "powerdown",
> + GPIOD_OUT_LOW);
> + if (IS_ERR(st->powerdown_gpio)) {
> + ret = PTR_ERR(st->powerdown_gpio);
> + dev_err(dev, "Failed to request powerdown GPIO: %d\n", ret);
> + return ret;
> + }
> +
> + if (!st->chip_info->is_ad778x)
> + return 0;
> +
nitpick: One blank line is always enough. More just reduces the amount of
code that can be seen at a time.

> +
> + st->gain_gpio = devm_gpiod_get_optional(dev,
> + "adi,gain",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(st->gain_gpio)) {
> + ret = PTR_ERR(st->gain_gpio);
> + dev_err(dev, "Failed to request gain GPIO: %d\n", ret);
> + return ret;
> + }
> +
> + st->filter_gpio = devm_gpiod_get_optional(dev,
> + "adi,filter",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(st->filter_gpio)) {
> + ret = PTR_ERR(st->filter_gpio);
> + dev_err(dev, "Failed to request filter GPIO: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int ad7780_probe(struct spi_device *spi)
> {
> struct ad7780_state *st;
> @@ -212,15 +296,9 @@ static int ad7780_probe(struct spi_device *spi)
> indio_dev->num_channels = 1;
> indio_dev->info = &ad7780_info;
>
> - st->powerdown_gpio = devm_gpiod_get_optional(&spi->dev,
> - "powerdown",
> - GPIOD_OUT_LOW);
> - if (IS_ERR(st->powerdown_gpio)) {
> - ret = PTR_ERR(st->powerdown_gpio);
> - dev_err(&spi->dev, "Failed to request powerdown GPIO: %d\n",
> - ret);
> - goto error_disable_reg;
> - }
> + ret = ad7780_init_gpios(&spi->dev, st);
> + if (ret)
> + goto error_cleanup_buffer_and_trigger;
>
> ret = ad_sd_setup_buffer_and_trigger(indio_dev);
> if (ret)