Commit Graph

595 Commits

Author SHA1 Message Date
Greg Kroah-Hartman 1676587bca First round of fixes for IIO in the 3.13 cycle.
The usual mixed bag of fixes.
 
 * 3 cases where kconfig dependencies were missing.  We need to keep a closer
   eye on this in new drivers.
 
 * hid_sensors was abusing the iio_dev->trigger pointer.  We had a round
   of clearing this out some time ago but this driver clearly slipped through.
 
 * A misuse of the IIO_ST macro, in mcp3422, which we should really make a
   concertive effort to finish removing.
 
 * Avoid a double free introduced by recent buffer reference counting in the
   one driver that (quite reasonably!) does things differently (am335x)
 
 * A missing mutex_unlock in kxsd9 that means that driver has been non
   functional for some time and no one noticed (including me who for once
   actually has one of the supported devices).
 
 * An incorrect assumption about the parameters of sign_extend32 in mcp3422.
 
 So nothing controversial.  The only substantial patch is the hid_sensors
 one and that is actually just adding a new pointer to the devices private
 state then moving the code over to it.
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Merge tag 'fixes-for-3.13a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

First round of fixes for IIO in the 3.13 cycle.

The usual mixed bag of fixes.

* 3 cases where kconfig dependencies were missing.  We need to keep a closer
  eye on this in new drivers.

* hid_sensors was abusing the iio_dev->trigger pointer.  We had a round
  of clearing this out some time ago but this driver clearly slipped through.

* A misuse of the IIO_ST macro, in mcp3422, which we should really make a
  concertive effort to finish removing.

* Avoid a double free introduced by recent buffer reference counting in the
  one driver that (quite reasonably!) does things differently (am335x)

* A missing mutex_unlock in kxsd9 that means that driver has been non
  functional for some time and no one noticed (including me who for once
  actually has one of the supported devices).

* An incorrect assumption about the parameters of sign_extend32 in mcp3422.

So nothing controversial.  The only substantial patch is the hid_sensors
one and that is actually just adding a new pointer to the devices private
state then moving the code over to it.
2013-11-25 12:50:11 -08:00
Frank Zago 0ee005c7dc iio:accel:kxsd9 fix missing mutex unlock
This will leave a lock held after reading from the device, preventing
any further reads.

Signed-off-by: Frank Zago <frank@zago.net>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-17 15:22:00 +00:00
Stefani Seibold 498d319bb5 kfifo API type safety
This patch enhances the type safety for the kfifo API.  It is now safe
to put const data into a non const FIFO and the API will now generate a
compiler warning when reading from the fifo where the destination
address is pointing to a const variable.

As a side effect the kfifo_put() does now expect the value of an element
instead a pointer to the element.  This was suggested Russell King.  It
make the handling of the kfifo_put easier since there is no need to
create a helper variable for getting the address of a pointer or to pass
integers of different sizes.

IMHO the API break is okay, since there are currently only six users of
kfifo_put().

The code is also cleaner by kicking out the "if (0)" expressions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:23 +09:00
Wolfram Sang 16735d022f tree-wide: use reinit_completion instead of INIT_COMPLETION
Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:21 +09:00
Lars-Peter Clausen fe26980e03 iio: adc: ti_am335x_adc: avoid double free of buffer.
The driver is missing the iio_buffer_attach() call. As such it will attempt
to free the buffer twice on removal.

Introduced in commit 9e69c9 ("iio: Add reference counting for buffers").

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-09 12:33:24 +00:00
Peter Meerwald 089b54bd69 iio: Fix tcs3472 Kconfig dependencies
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-09 12:15:57 +00:00
Peter Meerwald 50619cb173 iio: Fix mag3110 Kconfig dependencies
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-09 12:15:34 +00:00
Peter Meerwald 911bdc68ec iio: Fix mag3110 scan_type
last argument of IIO_ST is shift, not endianness

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-09 12:12:33 +00:00
Peter Meerwald a5a3e43111 iio: Fix sign extension table in mcp3422 driver
the index argument to sign_extend32() gives the bit position (from 0)
to the sign bit

so e.g. if the measurement has 16-bit resolution, we need to pass 15;
a measurement of 0x8000 should be reported as -32768, not 32768

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-05 22:45:25 +00:00
Srinivas Pandruvada ec7f68e07b iio: hid_Sensors: fix crash during trigger unregister
We can't store the trigger instance created by iio_trigger_alloc, in
trig field of iio_device structure. This needs to be stored in the
driver private data. Othewise it can result in crash during module
unload. Hence created a trig_ptr in the common data structure
for each HID sensor IIO driver and storing here.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-02 19:07:06 +00:00
Wei Yongjun 00582bf8e7 iio: at91: fix error return code in at91_adc_probe()
Fix to return -ENODEV instead of 0 if non-TSMR adc don't
support, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-02 12:07:54 +00:00
Sachin Kamat e020325541 iio: light: vcnl4000: Remove redundant code
The if check is redundant as the value obtained from
iio_device_register() is already in the required format.
Hence return the function directly.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:48:14 +01:00
Sachin Kamat a9b6851100 iio: dac: mcp4725: Remove redundant code
Remove an inconsequential print message and return directly
thereby cleaning up some code.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:47:49 +01:00
Sachin Kamat 345d4f92e7 iio: dac: max517: Remove redundant variable
Remove an inconsequential print message and return directly
thereby eliminating an intermediate variable.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:47:15 +01:00
Sachin Kamat e2f5543a73 iio: dac: ad5755: Remove redundant code
The if check is redundant as the value obtained from
iio_device_register() is already in the required format.
Error messages are already printed by iio_device_register();
hence not needed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:46:33 +01:00
Sachin Kamat 35b9c0b18e iio: dac: ad5421: Remove redundant code
The if check is redundant as the value obtained from
iio_device_register() is already in the required format.
Hence return the function directly. Error messages are already
printed by iio_device_register(); hence not needed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:46:00 +01:00
Sachin Kamat ae0f29d159 iio: adc: twl6030-gpadc: Remove redundant code
The if check is redundant as the value obtained from
iio_device_register() is already in the required format.
Hence return the function directly.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:45:09 +01:00
Sachin Kamat dcf5272cac iio: accel: kxsd9: Remove redundant variable
Return directly thereby eliminating an intermediate variable.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:43:24 +01:00
Sachin Kamat 670c11033d iio: core: Add misssing braces
Silences the following checkpatch warning:
WARNING: sizeof *iio_attr should be sizeof(*iio_attr)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:42:44 +01:00
Sachin Kamat 3176dd5d3b iio: core: Use pr_err instead of printk
Use of pr_err is preferred to printk.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:39:48 +01:00
Denis CIOCCA d141ab776b iio:pressure: Adds LPS001WP support also on spi interface and Kconfig fix
Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-23 17:55:14 +01:00
Sachin Kamat de06b344ac iio: adc: ti_am335x_adc: Remove redundant of_match_ptr
ti_adc_dt_ids is always compiled in. Hence of_match_ptr is not
needed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-23 17:52:25 +01:00
Sachin Kamat d453a4ab11 iio: adc: nau7802: Remove redundant of_match_ptr
nau7802_dt_ids is always compiled in. Hence of_match_ptr is not
needed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-23 17:52:25 +01:00
Sachin Kamat fc21acc471 iio: adc: twl6030-gpadc: Remove redundant of_match_ptr
of_twl6030_match_tbl is always compiled in. Hence of_match_ptr is
not necessary.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-23 17:51:24 +01:00
Peter Meerwald 39631b5f95 iio: Add Freescale mag3110 magnetometer driver
three-axis digital magnetometer with I2C interface

datasheet is available from
http://cache.freescale.com/files/sensors/doc/data_sheet/MAG3110.pdf

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-23 17:43:11 +01:00
Vivien Didelot 61bdda6922 iio:adc:max1363 support SMBus for 8-bit devices
The driver currently supports only I2C access. But supported devices with an
accuracy of 8-bit are compatible with the SMBus byte access routines.

This patch wraps the send and receive routines depending on the chip
accuracy and fonctionnalities of its adapter.

For instance, this allows us to use a MAX11603 on a ICH7 controller.

This patch also simplifies the max1363_write_basic_config() routine to
use the struct max1363_state fields directly.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-20 22:36:21 +01:00
Peter Meerwald eb03610a9c iio: Correct description how to convert microtesla to gauss
this just fixes the comment; however, I'm not sure if the driver reports
measurements correctly; the raw values are 0.3 uT / LSB; IIO is supposed
to report magnetic fields in Gauss, so the scale should be around 1/300
(ignoring ASA) -- but value and scale are returned as VAL_INT

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-20 22:36:13 +01:00
Greg Kroah-Hartman f7a0fd56e4 Merge 3.12-rc6 into staging-next.
We want these fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-19 13:14:34 -07:00
Sachin Kamat 43e01beda4 iio: light: gp2ap020a00f: Include linux/of.h header
'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-18 20:05:57 +01:00
Sachin Kamat 1f100e80bb iio: adc: ti-adc081c: Include linux/of.h header
'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-18 20:05:56 +01:00
Sachin Kamat 62ba493ea4 iio: adc: nau7802: Include linux/of.h header
'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-18 20:05:56 +01:00
Sachin Kamat de36d817b4 iio: adc: mcp3422: Include linux/of.h header
'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-18 20:05:56 +01:00
Josh Wu c8b11de040 iio: at91: introduce touch screen support in iio adc driver
AT91 ADC hardware integrate touch screen support. So this patch add touch
screen support for at91 adc iio driver.
To enable touch screen support in adc, you need to add the dt parameters:
  1. which type of touch are used? (4 or 5 wires), sample period time.
  2. correct pressure detect threshold value.

In the meantime, since touch screen will use a interal period trigger of adc,
so it is conflict to other hardware triggers. Driver will disable the hardware
trigger support if touch screen is enabled.

This driver has been tested in AT91SAM9X5-EK and SAMA5D3x-EK.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
CC: devicetree@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-17 23:57:10 +01:00
Beomho Seo e590d45190 iio: cm36651: Add CM36651 proximity/light sensor
This patch adds a new driver for Capella CM36651 proximity and RGB sensor.

Signed-off-by: Beomho Seo <beomho.seo@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-17 23:40:19 +01:00
Lars-Peter Clausen bf741c08af iio: Remove unused iio_sw_buffer_preenable()
The functionality implemented by iio_sw_buffer_preenable() is now done directly
in the IIO core and previous users of iio_sw_buffer_preenable() have all been
updated to not use it anymore. It is unused now and can be remove.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:17:06 +01:00
Lars-Peter Clausen 1e61fb7b19 iio:gp2ap020a00f: Remove redundant call to iio_sw_buffer_preenable()
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:13:57 +01:00
Lars-Peter Clausen 6c0743ed99 iio:st_pressure: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:13:56 +01:00
Lars-Peter Clausen bbc1751d24 iio:st_magn: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:13:50 +01:00
Lars-Peter Clausen c80b8ea9b4 iio:triggered-buffer: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:12:47 +01:00
Lars-Peter Clausen d4b2911b1f iio:st_gyro: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:12:46 +01:00
Lars-Peter Clausen 24adaf7958 iio:ti_am335x: Remove redundant call to iio_sw_buffer_preenable()
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer
core, so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:12:46 +01:00
Lars-Peter Clausen eddcee851a iio:ad_sigma_delta: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:12:40 +01:00
Lars-Peter Clausen 41288e0f62 iio:ad7887: Remove redundant call to iio_sw_buffer_preenable().
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:12:04 +01:00
Lars-Peter Clausen 06e1b542bb iio:ad7266: Remove redundant call to iio_sw_preenable()
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:11:31 +01:00
Lars-Peter Clausen d0894cab0f iio:st_accel: Drop redundant call to iio_sw_buffer_preenable()
The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:11:11 +01:00
Lars-Peter Clausen 8e050996c8 iio: Update buffer's bytes per datum after updating the scan mask
Currently a IIO device driver needs to make sure to update the buffer's bytes
per datum after the scan mask has changed. This is usually done in the preenable
callback by invoking iio_sw_buffer_preenable(). This is something that needs to
be done and is done for virtually all devices which support buffers (we
currently have only one exception). Also this a bit of a layering violation
since we have to call the buffer setup ops from the device setup ops. This
requires the device driver to know about the internal requirements of the buffer
(e.g. whether we need to call the set_bytes_per_datum) callback. And especially
with in-kernel buffer consumers, which allows to attach arbitrary buffers to a
device, this is something that the driver can't know.

Moving this to the core allows us to drop the individual calls to
iio_sw_buffer_preenable() from drivers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-16 19:09:27 +01:00
Lars-Peter Clausen e086ed7667 iio:buffer: Free active scan mask in iio_disable_all_buffers()
Usually the active scan mask is freed in __iio_update_buffers() when the buffer
is disabled. But when the device is still sampling when it is removed we'll end
up disabling the buffers in iio_disable_all_buffers(). So we also need to free
the active scan mask here, otherwise it will be leaked.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-15 19:26:43 +01:00
Lars-Peter Clausen cb6fbfa138 iio:kfifo: Set update_needed to false after allocating a new buffer
update_needed is used to decide whether the kfifo buffer needs to be
re-allocated. It is set to true whenever the size of the buffer is changed. It
is never set to false though, causing the buffer to always be re-allocated.
Setting update_needed to false after the new buffer has been allocated fixes the
problem.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-15 19:20:55 +01:00
Lars-Peter Clausen 5b78e5138e iio:kfifo: Empty buffer on update
The kfifo's request_update callback will free the current buffer and allocate a
new one if the size has changed. This will remove any samples that might still
be left in the buffer. If the size has not changed the buffer content is
left untouched though. This is a bit inconsistent and might cause an application
to see data from a previous capture. This patch inserts a call to
kfifo_reset_out() when the size did not change. This makes sure that any pending
samples are removed from the buffer.

Note, due to a different bug the buffer is currently always re-allocated, even
if the size did not change. So this patch will not change the behavior. In the
next patch the bug will be fixed and this patch makes sure that the current
behavior is kept.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-15 19:20:51 +01:00
Lars-Peter Clausen 0894d80dfd iio:kfifo: Protect against concurrent access from userspace
It is possible for userspace to concurrently access the buffer from multiple
threads or processes. To avoid corruption of the internal state of the buffer we
need to add proper locking. It is possible for multiple processes to try to read
from the buffer concurrently and it is also possible that one process causes a
buffer re-allocation while a different process still access the buffer. Both can
be fixed by protecting the calls to kfifo_to_user() and kfifo_alloc() by the
same mutex. In iio_read_first_n_kfifo() we also use kfifo_recsize() instead of
the buffers bytes_per_datum to avoid a race that can happen if bytes_per_datum
has been changed, but the buffer has not been reallocated yet.

Note that all access to the buffer from within the kernel is already properly
synchronized, so there is no need for extra locking in iio_store_to_kfifo().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-15 19:19:22 +01:00