Some LRADC channels have fixed pre-dividers and all have an optional
divider by two which allows a maximum input voltage of VDDIO - 50mV.
This patch
- adds the scaling info flag to all channels
- grabs the max reference voltage per channel from DT
(where the fixed pre-dividers apply)
- allows to read the scaling attribute (computed from the Vref)
Signed-off-by: Hector Palacios <hector.palac...@digi.com>.
---
drivers/staging/iio/adc/mxs-lradc.c | 81 ++++++++++++++++++++++++-------------
1 file changed, 52 insertions(+), 29 deletions(-)
diff --git a/drivers/staging/iio/adc/mxs-lradc.c
b/drivers/staging/iio/adc/mxs-lradc.c
index 91282dc..99e5790 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -141,6 +141,8 @@ struct mxs_lradc {
struct completion completion;
+ uint32_t vref_mv[LRADC_MAX_TOTAL_CHANS];
+
/*
* Touchscreen LRADC channels receives a private slot in the CTRL4
* register, the slot #7. Therefore only 7 slots instead of 8 in the
@@ -228,39 +230,12 @@ struct mxs_lradc {
#define LRADC_RESOLUTION 12
#define LRADC_SINGLE_SAMPLE_MASK ((1 << LRADC_RESOLUTION) - 1)
-/*
- * Raw I/O operations
- */
-static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
+static int mxs_lradc_read_single(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long m)
{
struct mxs_lradc *lradc = iio_priv(iio_dev);
int ret;
- unsigned long mask;
-
- if (m != IIO_CHAN_INFO_RAW)
- return -EINVAL;
-
- /* Check for invalid channel */
- if (chan->channel > LRADC_MAX_TOTAL_CHANS)
- return -EINVAL;
-
- /* Validate the channel if it doesn't intersect with reserved chans. */
- bitmap_set(&mask, chan->channel, 1);
- ret = iio_validate_scan_mask_onehot(iio_dev, &mask);
- if (ret)
- return -EINVAL;
-
- /*
- * See if there is no buffered operation in progess. If there is, simply
- * bail out. This can be improved to support both buffered and raw IO at
- * the same time, yet the code becomes horribly complicated. Therefore I
- * applied KISS principle here.
- */
- ret = mutex_trylock(&lradc->lock);
- if (!ret)
- return -EBUSY;
INIT_COMPLETION(lradc->completion);
@@ -300,6 +275,47 @@ err:
writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+ return ret;
+}
+
+/*
+ * Raw I/O operations
+ */
+static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int *val, int *val2, long m)
+{
+ struct mxs_lradc *lradc = iio_priv(iio_dev);
+ int ret;
+
+ /*
+ * See if there is no buffered operation in progress. If there is,
simply
+ * bail out. This can be improved to support both buffered and raw IO at
+ * the same time, yet the code becomes horribly complicated. Therefore I
+ * applied KISS principle here.
+ */
+ ret = mutex_trylock(&lradc->lock);
+ if (!ret)
+ return -EBUSY;
+
+ /* Check for invalid channel */
+ if (chan->channel > LRADC_MAX_TOTAL_CHANS)
+ ret = -EINVAL;
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ ret = mxs_lradc_read_single(iio_dev, chan, val, val2, m);
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ *val = lradc->vref_mv[chan->channel];
+ *val2 = chan->scan_type.realbits;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
mutex_unlock(&lradc->lock);
return ret;
@@ -821,7 +837,8 @@ static const struct iio_buffer_setup_ops
mxs_lradc_buffer_ops = {
.type = (chan_type), \
.indexed = 1, \
.scan_index = (idx), \
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
.channel = (idx), \
.scan_type = { \
.sign = 'u', \
@@ -960,6 +977,12 @@ static int mxs_lradc_probe(struct platform_device *pdev)
goto err_addr;
}
+ /* Grab Vref array from DT */
+ ret = of_property_read_u32_array(node, "fsl,vref", lradc->vref_mv,
+ LRADC_MAX_TOTAL_CHANS);
+ if (ret)
+ goto err_addr;
+
platform_set_drvdata(pdev, iio);
init_completion(&lradc->completion);
--
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