Some LRADC channels have a fixed pre-divider, and all can have enabled
an optional divisor by two which allows a maximum input voltage of
VDDIO - 50mV.
This patch
- adds the scaling info flag to all channels
- adds a lookup table with max reference voltage per channel
(where the fixed pre-dividers apply)
- allows to read the scaling attribute (computed from the Vref)
Signed-off-by: Hector Palacios <hector.palacios@xxxxxxxx>
---
drivers/staging/iio/adc/mxs-lradc.c | 122 +++++++++++++++++++++++++++---------
1 file changed, 93 insertions(+), 29 deletions(-)
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index d65a594..012c42e 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -107,19 +107,63 @@ static const char * const mx28_lradc_irq_names[] = {
"mxs-lradc-button1",
};
+/*
+ * Max reference voltage (mV) for each channel
+ */
+static const int mx23_vref_mv[LRADC_MAX_TOTAL_CHANS] = {
+ 1850, /* CH0 */
+ 1850, /* CH1 */
+ 1850, /* CH2 */
+ 1850, /* CH3 */
+ 1850, /* CH4 */
+ 1850, /* CH5 */
+ 1850 * 2, /* CH6 VDDIO */
+ 1850 * 4, /* CH7 VBATT */
+ 1850, /* CH8 Temp sense 0 */
+ 1850, /* CH9 Temp sense 1 */
+ 1850, /* CH10 */
+ 1850, /* CH11 */
+ 1850, /* CH12 USB_DP */
+ 1850, /* CH13 USB_DN */
+ 1850, /* CH14 VBG */
+ 1850 * 4, /* CH15 VDD5V */
+};
+
+static const int mx28_vref_mv[LRADC_MAX_TOTAL_CHANS] = {
+ 1850, /* CH0 */
+ 1850, /* CH1 */
+ 1850, /* CH2 */
+ 1850, /* CH3 */
+ 1850, /* CH4 */
+ 1850, /* CH5 */
+ 1850, /* CH6 */
+ 1850 * 4, /* CH7 VBATT */
+ 1850, /* CH8 Temp sense 0 */
+ 1850, /* CH9 Temp sense 1 */
+ 1850 * 2, /* CH10 VDDIO */
+ 1850, /* CH11 VTH */
+ 1850 * 2, /* CH12 VDDA */
+ 1850, /* CH13 VDDD */
+ 1850, /* CH14 VBG */
+ 1850 * 4, /* CH15 VDD5V */
+};
+
struct mxs_lradc_of_config {
const int irq_count;
const char * const *irq_name;
+ const int *vref_mv;
};
static const struct mxs_lradc_of_config mxs_lradc_of_config[] = {
[IMX23_LRADC] = {
.irq_count = ARRAY_SIZE(mx23_lradc_irq_names),
.irq_name = mx23_lradc_irq_names,
+ .vref_mv = mx23_vref_mv,
},
[IMX28_LRADC] = {
.irq_count = ARRAY_SIZE(mx28_lradc_irq_names),
.irq_name = mx28_lradc_irq_names,
+ .vref_mv = mx28_vref_mv,
},
};
@@ -141,6 +185,8 @@ struct mxs_lradc {
struct completion completion;
+ const int *vref_mv;
+
/*
* Touchscreen LRADC channels receives a private slot in the CTRL4
* register, the slot #7. Therefore only 7 slots instead of 8 in the
@@ -225,39 +271,12 @@ struct mxs_lradc {
#define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
#define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
-/*
- * 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);
@@ -297,6 +316,47 @@ 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;
@@ -818,7 +878,8 @@ 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', \
@@ -957,6 +1018,9 @@ static int mxs_lradc_probe(struct platform_device *pdev)
goto err_addr;
}
+ /* Set pointer to Vref array */
+ lradc->vref_mv = of_cfg->vref_mv;
+
platform_set_drvdata(pdev, iio);
init_completion(&lradc->completion);
--
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