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Subject[PATCH] iio: light: acpi-als: Add a tuning parameter interface.
Date
From: Bryan Freed <bfreed@chromium.org>

Add IIO_CHAN_INFO_CALIBSCALE to the channel to scale up or down
the raw measurements through the IIO framework.

Add IIO_CHAN_INFO_PROCESSED to provide the interface to read the
scaled measurements through the in_illuminance_input file.

Signed-off-by: Bryan Freed <bfreed@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
drivers/iio/light/acpi-als.c | 59 +++++++++++++++++++++++++++++++++++++-------
1 file changed, 50 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
index f0b47c5..40837bc 100644
--- a/drivers/iio/light/acpi-als.c
+++ b/drivers/iio/light/acpi-als.c
@@ -56,7 +56,8 @@ static const struct iio_chan_spec acpi_als_channels[] = {
},
/* _RAW is here for backward ABI compatibility */
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
- BIT(IIO_CHAN_INFO_PROCESSED),
+ BIT(IIO_CHAN_INFO_PROCESSED) |
+ BIT(IIO_CHAN_INFO_CALIBSCALE),
},
};

@@ -76,6 +77,9 @@ struct acpi_als {
struct mutex lock;

s32 evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
+
+ uint als_scale;
+ uint als_uscale;
};

/*
@@ -154,25 +158,60 @@ static int acpi_als_read_raw(struct iio_dev *indio_dev,
s32 temp_val;
int ret;

- if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
- return -EINVAL;
-
/* we support only illumination (_ALI) so far. */
if (chan->type != IIO_LIGHT)
return -EINVAL;

- ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
- if (ret < 0)
- return ret;
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ case IIO_CHAN_INFO_PROCESSED:
+ ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
+ if (ret < 0)
+ return ret;
+ if (mask == IIO_CHAN_INFO_PROCESSED) {
+ /* use u64 to avoid overflow */
+ u64 ulux = (u64) temp_val * 1000000;
+
+ mutex_lock(&als->lock);
+ ulux = ulux * als->als_scale +
+ div_u64(ulux * als->als_uscale, 1000000U);
+ mutex_unlock(&als->lock);
+ *val = div_u64(ulux, 1000000U);
+ } else {
+ *val = temp_val;
+ }
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_CALIBSCALE:
+ mutex_lock(&als->lock);
+ *val = als->als_scale;
+ *val2 = als->als_uscale;
+ mutex_unlock(&als->lock);
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}

- *val = temp_val;
+static int acpi_als_write_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct acpi_als *als = iio_priv(iio);
+
+ if (mask != IIO_CHAN_INFO_CALIBSCALE || chan->type != IIO_LIGHT)
+ return -EINVAL;

- return IIO_VAL_INT;
+ mutex_lock(&als->lock);
+ als->als_scale = val;
+ als->als_uscale = val2;
+ mutex_unlock(&als->lock);
+ return 0;
}

static const struct iio_info acpi_als_info = {
.driver_module = THIS_MODULE,
.read_raw = acpi_als_read_raw,
+ .write_raw = acpi_als_write_raw,
};

static int acpi_als_add(struct acpi_device *device)
@@ -189,6 +228,8 @@ static int acpi_als_add(struct acpi_device *device)

device->driver_data = indio_dev;
als->device = device;
+ als->als_scale = 1;
+ als->als_uscale = 0;
mutex_init(&als->lock);

indio_dev->name = ACPI_ALS_DEVICE_NAME;
--
2.1.0
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