staging: iio: ad7780: add gain & filter gpio support

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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
index c4a8578..a7e0042 100644 (file)
--- 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_ULL(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;
+
+
+       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)