[PATCH v2 1/6] iio: sx9310: Support hardware gain factor

From: Stephen Boyd
Date: Wed Sep 30 2020 - 03:57:33 EST

Add support to set the hardware gain of the channels as a multiplier of
2x, 4x, or 8x.

Cc: Daniel Campello <campello@xxxxxxxxxxxx>
Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
Cc: Evan Green <evgreen@xxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
drivers/iio/proximity/sx9310.c | 109 +++++++++++++++++++++++++++++++--
1 file changed, 104 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
index 9d72d08ab9e7..030397a85845 100644
--- a/drivers/iio/proximity/sx9310.c
+++ b/drivers/iio/proximity/sx9310.c
@@ -16,6 +16,7 @@
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/kernel.h>
+#include <linux/log2.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pm.h>
@@ -51,7 +52,9 @@
#define SX9310_REG_PROX_CTRL2_COMBMODE_CS1_CS2 (0x02 << 6)
#define SX9310_REG_PROX_CTRL2_SHIELDEN_DYNAMIC (0x01 << 2)
#define SX9310_REG_PROX_CTRL3 0x13
+#define SX9310_REG_PROX_CTRL3_GAIN0_MASK GENMASK(3, 2)
#define SX9310_REG_PROX_CTRL3_GAIN0_X8 (0x03 << 2)
+#define SX9310_REG_PROX_CTRL3_GAIN12_MASK GENMASK(1, 0)
#define SX9310_REG_PROX_CTRL3_GAIN12_X4 0x02
#define SX9310_REG_PROX_CTRL4 0x14
#define SX9310_REG_PROX_CTRL4_RESOLUTION_FINEST 0x07
@@ -145,15 +148,18 @@ static const struct iio_event_spec sx9310_events[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_EITHER,
- .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE) | BIT(IIO_EV_INFO_VALUE),
},
};

#define SX9310_NAMED_CHANNEL(idx, name) \
{ \
.type = IIO_PROXIMITY, \
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+ .info_mask_separate_available = \
+ BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
.indexed = 1, \
.channel = idx, \
.extend_name = name, \
@@ -426,6 +432,34 @@ static int sx9310_read_proximity(struct sx9310_data *data,
return ret;
}

+static int sx9310_read_gain(struct sx9310_data *data,
+ const struct iio_chan_spec *chan, int *val)
+{
+ unsigned int regval, gain;
+ int ret;
+
+ ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL3, &regval);
+ if (ret)
+ return ret;
+
+ switch (chan->channel) {
+ case 0:
+ case 3:
+ gain = FIELD_GET(SX9310_REG_PROX_CTRL3_GAIN0_MASK, regval);
+ break;
+ case 1:
+ case 2:
+ gain = FIELD_GET(SX9310_REG_PROX_CTRL3_GAIN12_MASK, regval);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ *val = 1 << gain;
+
+ return IIO_VAL_INT;
+}
+
static int sx9310_read_samp_freq(struct sx9310_data *data, int *val, int *val2)
{
unsigned int regval;
@@ -461,6 +495,14 @@ static int sx9310_read_raw(struct iio_dev *indio_dev,
ret = sx9310_read_proximity(data, chan, val);
iio_device_release_direct_mode(indio_dev);
return ret;
+ case IIO_CHAN_INFO_HARDWAREGAIN:
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
+
+ ret = sx9310_read_gain(data, chan, val);
+ iio_device_release_direct_mode(indio_dev);
+ return ret;
case IIO_CHAN_INFO_SAMP_FREQ:
return sx9310_read_samp_freq(data, val, val2);
default:
@@ -468,6 +510,27 @@ static int sx9310_read_raw(struct iio_dev *indio_dev,
}
}

+static const int sx9310_gain_vals[] = { 1, 2, 4, 8 };
+
+static int sx9310_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long mask)
+{
+ if (chan->type != IIO_PROXIMITY)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_HARDWAREGAIN:
+ *type = IIO_VAL_INT;
+ *length = ARRAY_SIZE(sx9310_gain_vals);
+ *vals = sx9310_gain_vals;
+ return IIO_AVAIL_LIST;
+ }
+
+ return -EINVAL;
+}
+
static int sx9310_set_samp_freq(struct sx9310_data *data, int val, int val2)
{
int i, ret;
@@ -492,6 +555,37 @@ static int sx9310_set_samp_freq(struct sx9310_data *data, int val, int val2)
return ret;
}

+static int sx9310_write_gain(struct sx9310_data *data,
+ const struct iio_chan_spec *chan, int val)
+{
+ unsigned int gain, mask;
+ int ret;
+
+ gain = ilog2(val);
+
+ switch (chan->channel) {
+ case 0:
+ case 3:
+ mask = SX9310_REG_PROX_CTRL3_GAIN0_MASK;
+ gain = FIELD_PREP(SX9310_REG_PROX_CTRL3_GAIN0_MASK, gain);
+ break;
+ case 1:
+ case 2:
+ mask = SX9310_REG_PROX_CTRL3_GAIN12_MASK;
+ gain = FIELD_PREP(SX9310_REG_PROX_CTRL3_GAIN12_MASK, gain);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ mutex_lock(&data->mutex);
+ ret = regmap_update_bits(data->regmap, SX9310_REG_PROX_CTRL3, mask,
+ gain);
+ mutex_unlock(&data->mutex);
+
+ return ret;
+}
+
static int sx9310_write_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int val, int val2,
long mask)
@@ -501,10 +595,14 @@ static int sx9310_write_raw(struct iio_dev *indio_dev,
if (chan->type != IIO_PROXIMITY)
return -EINVAL;

- if (mask != IIO_CHAN_INFO_SAMP_FREQ)
- return -EINVAL;
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ return sx9310_set_samp_freq(data, val, val2);
+ case IIO_CHAN_INFO_HARDWAREGAIN:
+ return sx9310_write_gain(data, chan, val);
+ }

- return sx9310_set_samp_freq(data, val, val2);
+ return -EINVAL;
}

static irqreturn_t sx9310_irq_handler(int irq, void *private)
@@ -645,6 +743,7 @@ static const struct attribute_group sx9310_attribute_group = {
static const struct iio_info sx9310_info = {
.attrs = &sx9310_attribute_group,
.read_raw = sx9310_read_raw,
+ .read_avail = sx9310_read_avail,
.write_raw = sx9310_write_raw,
.read_event_config = sx9310_read_event_config,
.write_event_config = sx9310_write_event_config,
--
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