iio: mxs-lradc: add write_raw function to modify scale

Added write_raw function to manipulate the optional divider_by_two
through the scaling attribute out of the available scales.

Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index c63b312e54fd1b2681128518e98b4e6798089efd..a58c6aaa94d357cda7a05179ef97ded8cc5cf2e8 100644 (file)
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -185,6 +185,11 @@ enum lradc_ts_plate {
        LRADC_SAMPLE_VALID,
 };
 
+enum mxs_lradc_divbytwo {
+       MXS_LRADC_DIV_DISABLED = 0,
+       MXS_LRADC_DIV_ENABLED,
+};
+
 struct mxs_lradc_scale {
        unsigned int            integer;
        unsigned int            nano;
@@ -206,6 +211,7 @@ struct mxs_lradc {
 
        const uint32_t          *vref_mv;
        struct mxs_lradc_scale  scale_avail[LRADC_MAX_TOTAL_CHANS][2];
+       unsigned int            is_divided[LRADC_MAX_TOTAL_CHANS];
 
        /*
         * Touchscreen LRADC channels receives a private slot in the CTRL4
@@ -295,6 +301,7 @@ struct mxs_lradc {
 #define        LRADC_CTRL1_LRADC_IRQ_OFFSET            0
 
 #define        LRADC_CTRL2                             0x20
+#define        LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET        24
 #define        LRADC_CTRL2_TEMPSENSE_PWD               (1 << 15)
 
 #define        LRADC_STATUS                            0x40
@@ -912,7 +919,8 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
                }
 
                *val = lradc->vref_mv[chan->channel];
-               *val2 = chan->scan_type.realbits;
+               *val2 = chan->scan_type.realbits -
+                       lradc->is_divided[chan->channel];
                return IIO_VAL_FRACTIONAL_LOG2;
 
        case IIO_CHAN_INFO_OFFSET:
@@ -936,6 +944,56 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
        return -EINVAL;
 }
 
+static int mxs_lradc_write_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);
+       struct mxs_lradc_scale *scale_avail =
+                       lradc->scale_avail[chan->channel];
+       int ret;
+
+       ret = mutex_trylock(&lradc->lock);
+       if (!ret)
+               return -EBUSY;
+
+       switch (m) {
+       case IIO_CHAN_INFO_SCALE:
+               ret = -EINVAL;
+               if (val == scale_avail[MXS_LRADC_DIV_DISABLED].integer &&
+                   val2 == scale_avail[MXS_LRADC_DIV_DISABLED].nano) {
+                       /* divider by two disabled */
+                       writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
+                              lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_CLR);
+                       lradc->is_divided[chan->channel] = 0;
+                       ret = 0;
+               } else if (val == scale_avail[MXS_LRADC_DIV_ENABLED].integer &&
+                          val2 == scale_avail[MXS_LRADC_DIV_ENABLED].nano) {
+                       /* divider by two enabled */
+                       writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
+                              lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_SET);
+                       lradc->is_divided[chan->channel] = 1;
+                       ret = 0;
+               }
+
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       mutex_unlock(&lradc->lock);
+
+       return ret;
+}
+
+static int mxs_lradc_write_raw_get_fmt(struct iio_dev *iio_dev,
+                                      const struct iio_chan_spec *chan,
+                                      long m)
+{
+       return IIO_VAL_INT_PLUS_NANO;
+}
+
 static ssize_t mxs_lradc_show_scale_available_ch(struct device *dev,
                struct device_attribute *attr,
                char *buf,
@@ -1013,6 +1071,8 @@ static const struct attribute_group mxs_lradc_attribute_group = {
 static const struct iio_info mxs_lradc_iio_info = {
        .driver_module          = THIS_MODULE,
        .read_raw               = mxs_lradc_read_raw,
+       .write_raw              = mxs_lradc_write_raw,
+       .write_raw_get_fmt      = mxs_lradc_write_raw_get_fmt,
        .attrs                  = &mxs_lradc_attribute_group,
 };