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Date: Sun, 27 Jan 2019 18:30:47 -0200
From: Renato Lui Geh <renatogeh@...il.com>
To: lars@...afoo.de, Michael.Hennerich@...log.com, jic23@...nel.org,
knaack.h@....de, pmeerw@...erw.net, gregkh@...uxfoundation.org,
stefan.popa@...log.com, alexandru.Ardelean@...log.com,
giuliano.belinassi@....br
Cc: linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
linux-kernel@...r.kernel.org, kernel-usp@...glegroups.com
Subject: [PATCH v2 1/2] 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@...il.com>
Signed-off-by: Giuliano Belinassi <giuliano.belinassi@....br>
Co-developed-by: Giuliano Belinassi <giuliano.belinassi@....br>
---
Changes in v2:
- Filter reading changed to mHz
- Storing filter, gain and voltage to chip_info
drivers/staging/iio/adc/ad7780.c | 103 ++++++++++++++++++++++---
include/linux/iio/adc/ad_sigma_delta.h | 5 ++
2 files changed, 99 insertions(+), 9 deletions(-)
diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
index c4a85789c2db..82394e31b168 100644
--- a/drivers/staging/iio/adc/ad7780.c
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -39,6 +39,15 @@
#define AD7170_PATTERN (AD7780_PAT0 | AD7170_PAT2)
#define AD7170_PATTERN_MASK (AD7780_PAT0 | AD7780_PAT1 | AD7170_PAT2)
+#define AD7780_GAIN_GPIO 0
+#define AD7780_FILTER_GPIO 1
+
+#define AD7780_GAIN_MIDPOINT 64
+#define AD7780_FILTER_MIDPOINT 13350
+
+static const unsigned int ad778x_gain[2] = { 1, 128 };
+static const unsigned int ad778x_filter[2] = { 10000, 16700 };
+
struct ad7780_chip_info {
struct iio_chan_spec channel;
unsigned int pattern_mask;
@@ -50,7 +59,11 @@ 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 filter;
+ unsigned int int_vref_mv;
struct ad_sigma_delta sd;
};
@@ -104,17 +117,65 @@ 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));
return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = st->filter;
+ return IIO_VAL_INT;
}
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;
+ int vref, gain;
+ unsigned int full_scale;
+
+ if (!chip_info->is_ad778x)
+ return 0;
+
+ 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;
+ st->filter = ad778x_filter[val];
+ gpiod_set_value(st->filter_gpio, val);
+ break;
+ }
+
+ return 0;
+}
+
static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
unsigned int raw_sample)
{
@@ -126,10 +187,8 @@ static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
return -EIO;
if (chip_info->is_ad778x) {
- if (raw_sample & AD7780_GAIN)
- st->gain = 1;
- else
- st->gain = 128;
+ st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
+ st->filter = ad778x_filter[raw_sample & AD7780_FILTER];
}
return 0;
@@ -141,18 +200,20 @@ static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
.has_registers = false,
};
-#define AD7780_CHANNEL(bits, wordsize) \
+#define AD7170_CHANNEL(bits, wordsize) \
AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, wordsize - bits)
+#define AD7780_CHANNEL(bits, wordsize) \
+ AD_SD_CHANNEL_GAIN_FILTER(1, 0, 0, bits, 32, wordsize - bits)
static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
[ID_AD7170] = {
- .channel = AD7780_CHANNEL(12, 24),
+ .channel = AD7170_CHANNEL(12, 24),
.pattern = AD7170_PATTERN,
.pattern_mask = AD7170_PATTERN_MASK,
.is_ad778x = false,
},
[ID_AD7171] = {
- .channel = AD7780_CHANNEL(16, 24),
+ .channel = AD7170_CHANNEL(16, 24),
.pattern = AD7170_PATTERN,
.pattern_mask = AD7170_PATTERN_MASK,
.is_ad778x = false,
@@ -173,6 +234,7 @@ 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_probe(struct spi_device *spi)
@@ -222,6 +284,29 @@ static int ad7780_probe(struct spi_device *spi)
goto error_disable_reg;
}
+ if (st->chip_info->is_ad778x) {
+ st->gain_gpio = devm_gpiod_get_optional(&spi->dev,
+ "gain",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(st->gain_gpio)) {
+ ret = PTR_ERR(st->gain_gpio);
+ dev_err(&spi->dev, "Failed to request gain GPIO: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+
+ st->filter_gpio = devm_gpiod_get_optional(&spi->dev,
+ "filter",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(st->filter_gpio)) {
+ ret = PTR_ERR(st->filter_gpio);
+ dev_err(&spi->dev,
+ "Failed to request filter GPIO: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+ }
+
ret = ad_sd_setup_buffer_and_trigger(indio_dev);
if (ret)
goto error_disable_reg;
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
index 7e84351fa2c0..c01da869de83 100644
--- a/include/linux/iio/adc/ad_sigma_delta.h
+++ b/include/linux/iio/adc/ad_sigma_delta.h
@@ -176,6 +176,11 @@ int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig);
__AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \
_storagebits, _shift, NULL, IIO_VOLTAGE, 0)
+#define AD_SD_CHANNEL_GAIN_FILTER(_si, _channel, _address, _bits, \
+ _storagebits, _shift) \
+ __AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \
+ _storagebits, _shift, NULL, IIO_VOLTAGE, BIT(IIO_CHAN_INFO_RAW))
+
#define AD_SD_TEMP_CHANNEL(_si, _address, _bits, _storagebits, _shift) \
__AD_SD_CHANNEL(_si, 0, -1, _address, _bits, \
_storagebits, _shift, NULL, IIO_TEMP, \
--
2.20.1
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