Hi Jonathan,
Le ven., août 19 2022 at 18:53:39 +0100, Jonathan Cameron
<jic23@xxxxxxxxxx> a écrit :
On Wed, 17 Aug 2022 12:56:43 +0200
Artur Rojek <contact@xxxxxxxxxxxxxx> wrote:
Don't try to access buffer data of a channel by its scan index.
Instead,
use the newly introduced `iio_find_channel_offset_in_buffer` to get
the
correct data offset.
The scan index of a channel does not represent its position in a
buffer,
as the buffer will contain data for enabled channels only, affecting
data offsets and alignment.
Fixes: 2c2b364fddd5 ("Input: joystick - add ADC attached joystick
driver.")
Reported-by: Chris Morgan <macromorgan@xxxxxxxxxxx>
Tested-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Signed-off-by: Artur Rojek <contact@xxxxxxxxxxxxxx>
---
drivers/input/joystick/adc-joystick.c | 26
+++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/drivers/input/joystick/adc-joystick.c
b/drivers/input/joystick/adc-joystick.c
index c0deff5d4282..aed853ebe1d1 100644
--- a/drivers/input/joystick/adc-joystick.c
+++ b/drivers/input/joystick/adc-joystick.c
@@ -6,6 +6,7 @@
#include <linux/ctype.h>
#include <linux/input.h>
#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
#include <linux/iio/consumer.h>
#include <linux/module.h>
#include <linux/platform_device.h>
@@ -46,36 +47,43 @@ static void adc_joystick_poll(struct input_dev
*input)
static int adc_joystick_handle(const void *data, void *private)
{
struct adc_joystick *joy = private;
+ struct iio_buffer *buffer;
enum iio_endian endianness;
- int bytes, msb, val, idx, i;
- const u16 *data_u16;
+ int bytes, msb, val, off;
+ const u8 *chan_data;
+ unsigned int i;
bool sign;
bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
for (i = 0; i < joy->num_chans; ++i) {
- idx = joy->chans[i].channel->scan_index;
endianness = joy->chans[i].channel->scan_type.endianness;
msb = joy->chans[i].channel->scan_type.realbits - 1;
sign = tolower(joy->chans[i].channel->scan_type.sign) == 's';
+ buffer = iio_channel_cb_get_iio_buffer(joy->buffer);
+ off = iio_find_channel_offset_in_buffer(joy->chans[i].indio_dev,
+ joy->chans[i].channel,
+ buffer);
With this call replaced with one that instead uses
off = iio_find_channel_offset_in_buffer(joy->chans, i);
which I'm fairly sure is enough via the info in chans[x]->channel to
establish this offset.
All is good, though you should probably cache it as doing that maths
every
time seems excessive.
+ if (off < 0)
+ return off;
+
+ chan_data = (const u8 *)data + off;
switch (bytes) {
case 1:
- val = ((const u8 *)data)[idx];
+ val = *chan_data;
break;
case 2:
- data_u16 = (const u16 *)data + idx;
-
/*
* Data is aligned to the sample size by IIO core.
* Call `get_unaligned_xe16` to hide type casting.
*/
if (endianness == IIO_BE)
- val = get_unaligned_be16(data_u16);
+ val = get_unaligned_be16(chan_data);
I obviously missed this previously but these are aligned so we don't
need the
unaligned form.
Yes, the comment above says that it's used to hide type casting.
Cheers,
-Paul
else if (endianness == IIO_LE)
- val = get_unaligned_le16(data_u16);
+ val = get_unaligned_le16(chan_data);
else /* IIO_CPU */
- val = *data_u16;
+ val = *(const u16 *)chan_data;
break;
default:
return -EINVAL;
