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authorHector Palacios <hector.palacios@digi.com>2013-07-22 15:03:00 +0100
committerJonathan Cameron <jic23@kernel.org>2013-08-17 15:50:57 +0100
commit1eb70a97452cacbe7aae752879b782e1e97a3484 (patch)
treea47fe7446d5ccea7c8b2be4942606e161594957f
parent1f5ac5279891140036e1000276b74adbc6c0b039 (diff)
iio: mxs-lradc: change the realbits to 12
The LRADC virtual channels have an 18 bit field to store the sum of up to 2^5 accumulated samples. The read_raw function however only operates over a single sample (12 bit resolution). In order to use this field for scaling operations, we need it to be the exact resolution value of the LRADC. Besides, the driver was using an 18 bit mask (LRADC_CH_VALUE_MASK) to report touch coordinates to userland. A 12 bit mask should be used instead or else the touch libraries will expect a coordinates range between 0 and 0x3ffff (18 bits), instead of between 0 and 0xfff (12 bits). Signed-off-by: Hector Palacios <hector.palacios@digi.com> Acked-by: Marek Vasut <marex@denx.de> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
-rw-r--r--drivers/staging/iio/adc/mxs-lradc.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index 863f0861b729..a08c1736458b 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -225,6 +225,9 @@ struct mxs_lradc {
#define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
#define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
+#define LRADC_RESOLUTION 12
+#define LRADC_SINGLE_SAMPLE_MASK ((1 << LRADC_RESOLUTION) - 1)
+
/*
* Raw I/O operations
*/
@@ -540,9 +543,10 @@ static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
__set_bit(EV_ABS, input->evbit);
__set_bit(EV_KEY, input->evbit);
__set_bit(BTN_TOUCH, input->keybit);
- input_set_abs_params(input, ABS_X, 0, LRADC_CH_VALUE_MASK, 0, 0);
- input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0);
- input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0);
+ input_set_abs_params(input, ABS_X, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
+ input_set_abs_params(input, ABS_Y, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
+ input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_SINGLE_SAMPLE_MASK,
+ 0, 0);
lradc->ts_input = input;
input_set_drvdata(input, lradc);
@@ -817,7 +821,7 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
.channel = (idx), \
.scan_type = { \
.sign = 'u', \
- .realbits = 18, \
+ .realbits = LRADC_RESOLUTION, \
.storagebits = 32, \
}, \
}