iio: sx9310: Support hardware gain factor

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

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Daniel Campello <campello@chromium.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Gwendal Grignou <gwendal@chromium.org>
Cc: Evan Green <evgreen@chromium.org>
Link: https://lore.kernel.org/r/20201007011735.1346994-2-swboyd@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
index 6d3f4ab..68a39c1 100644 (file)
--- 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 @@ out:
        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,