linux-kernel - [PATCH v2 1/5] iio: mxs-lradc: change the realbits to 12

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1374225208-28940-2-git-send-email-hector.palacios@digi.com>
Date:	Fri, 19 Jul 2013 11:13:24 +0200
From:	Hector Palacios <hector.palacios@...i.com>
To:	<linux-iio@...r.kernel.org>
CC:	<linux-kernel@...r.kernel.org>,
	<devicetree-discuss@...ts.ozlabs.org>, <marex@...x.de>,
	<alexandre.belloni@...e-electrons.com>, <jic23@...nel.org>,
	<lars@...afoo.de>, <fabio.estevam@...escale.com>,
	<hector.palacios@...i.com>
Subject: [PATCH v2 1/5] 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@...i.com>
---
 drivers/staging/iio/adc/mxs-lradc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index d92c97a..91282dc 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
  */
@@ -547,9 +550,10 @@ 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);
@@ -821,7 +825,7 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
 	.channel = (idx),					\
 	.scan_type = {						\
 		.sign = 'u',					\
-		.realbits = 18,					\
+		.realbits = LRADC_RESOLUTION,			\
 		.storagebits = 32,				\
 	},							\
 }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/