The ADC driver always programs all possible ADC values and discards
them except for the value IIO asked for. On the am335x-evm the driver
programs four values and it takes 500us to gather them. Reducing the number
of conversations down to the (required) one also reduces the busy loop down
to 125us.
This leads to another error, namely the FIFOCOUNT register is sometimes
(like one out of 10 attempts) not updated in time leading to EBUSY.
The next read has the FIFOCOUNT register updated.
Checking for the ADCSTAT register for being idle isn't a good choice either.
The problem is that if TSC is used at the same time, the HW completes the
conversation for ADC *and* before the driver noticed it, the HW begins to
perform a TSC conversation and so the driver never seen the HW idle. The
next time we would have two values in the FIFO but since the driver reads
everything we always see the current one.
So instead of polling for the IDLE bit in ADCStatus register, we should
check the FIFOCOUNT register. It should be one instead of zero because we
request one value.
This change in turn leads to another error. Sometimes if TSC & ADC are
used together the TSC starts generating interrupts even if nobody
actually touched the touchscreen. The interrupts seem valid because TSC's
FIFO is filled with values for each channel of the TSC. This condition stops
after a few ADC reads but will occur again. Not good.
On top of this (even without the changes I just mentioned) there is a ADC
& TSC lockup condition which was reported to me by Jeff Lance including the
following test case:
A busy loop of "cat /sys/bus/iio/devices/iio\:device0/in_voltage4_raw"
and a mug on touch screen. With this setup, the hardware will lockup after
something between 20 minutes and it could take up to a couple of hours.
During that lockup, the ADCSTAT register says 0x30 (or 0x70) which means
STEP_ID = IDLE and FSM_BUSY = yes. That means the hardware says that it is
idle and busy at the same time which is an invalid condition.
For all this reasons I decided to rework this TSC/ADC part and add a
handshake / synchronization here:
First the ADC signals that it needs the HW and writes a 0 mask into the
SE register. The HW (if active) will complete the current conversation
and become idle. The TSC driver will gather the values from the FIFO
(woken up by an interrupt) and won't "enable" another conversation.
Instead it will wake up the ADC driver which is already waiting. The ADC
driver will start "its" conversation and once it is done, it will
enable the TSC steps so the TSC will work again.
After this rework I haven't observed the lockup so far. Plus the busy
loop has been reduced from 500us to 125us.
The continues-read mode remains unchanged.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The update of the SE register in MFD doesn't look right as it has
nothing to do with it. The better place to do it is in TSC driver (which
is already doing it) and in the ADC driver which needs this only in the
continues mode.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The purpose of reg_se_cache has been defeated. It should avoid the
read-back of the register to avoid the latency and the fact that the
bits are reset to 0 after the individual conversation took place.
The reason why this is required like this to work, is that read-back of
the register removes the bits of the ADC so they do not start another
conversation after the register is re-written from the TSC side for the
update.
To avoid the not required read-back I introduce a "set once" variant which
does not update the cache mask. After the conversation completes, the
bit is removed from the SE register anyway and we don't plan a new
conversation "any time soon". The current set function is renamed to
set_cache to distinguish the two operations.
This is a small preparation for a larger sync-rework.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
It somehow looks like the ending bracket belongs to the if statement but
it does belong to the while loop. This patch moves the bracket where it
belongs.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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>
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>
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>
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>
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>
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>
'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>
'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>
'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>
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>
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>
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>
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>
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>
Switch the max1363 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Since in at91sam9x5, sama5d3x chip. the start up time calucation is changed.
This patch can choose different start up time calculation formula for different
chips.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This is a small, mainly to get a couple of compile bug related fixes into
the tree ASAP.
New device support:
1) Add ad5446 dac support to the ad5641 driver.
New functionality and cleanups:
1) Optional power supply regulators for the st pressure sensors drivers using
the new optional regulator interface.
2) Bit of tidying up of naming in the sysfs trigger.
Bug fixes from the previous series:
1) Missing select IIO_BUFFER for ti_am335x_adc
2) Drop a bonus bracket in iio-trig-bfin-timmer
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Merge tag 'iio-for-3.13b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next
Jonathan writes:
Second set of new functionality for IIO in the 3.13 cycle - with bug fixes for first set.
This is a small, mainly to get a couple of compile bug related fixes into
the tree ASAP.
New device support:
1) Add ad5446 dac support to the ad5641 driver.
New functionality and cleanups:
1) Optional power supply regulators for the st pressure sensors drivers using
the new optional regulator interface.
2) Bit of tidying up of naming in the sysfs trigger.
Bug fixes from the previous series:
1) Missing select IIO_BUFFER for ti_am335x_adc
2) Drop a bonus bracket in iio-trig-bfin-timmer
This avoids build problems such iio_push_to_buffers* not being defined.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
This resolves the merge problem with two iio drivers that Stephen
Rothwell pointed out.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver is functional without this error case. Cleaned up.
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Trigger related headers and variables are not needed
as driver is now based on INDIO_BUFFER_HARDWARE mode
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Static is missing in function header. Corrected.
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Makes the code a bit shorter and less ugly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Previously the driver had only one-shot reading functionality.
This patch adds continuous sampling support to the driver.
Continuous sampling starts when buffer is enabled.
HW IRQ wakes worker thread that pushes samples to userspace.
Sampling stops when buffer is disabled by userspace.
Patil Rachna (TI) laid the ground work for ADC HW register access.
Russ Dill (TI) fixed bugs in the driver relevant to FIFOs and IRQs.
I fixed channel scanning so multiple ADC channels can be read
simultaneously and pushed to userspace.
Restructured the driver to fit IIO ABI.
And added INDIO_BUFFER_HARDWARE mode.
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
12 bit ADC data is stored in 32 bits of storage.
Change from u32 to u16 to reduce wasted memory.
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
sizeof when applied to a pointer typed expression gives the size of the
pointer.
Found by coccinelle spatch "misc/noderef.cocci"
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
The adc_clk variable is currently defined using a 32-bits unsigned integer,
which will overflow under some very valid range of operations.
Such overflow will occur if, for example, the parent clock is set to a
20MHz frequency and the ADC startup time is larger than 215ns.
To fix this, introduce an intermediate variable holding the clock rate
in kHz.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
The max1361 driver uses the same callbacks as the triggered buffer default
buffer setup ops, so just remove the max1361 specific ops and let it use the
default ops.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Now that iio_push_to_buffers() takes a void pointer for the data parameter we
can remove those casts to u8*.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
For at91 boards, there are different IPs for adc. Different IPs has different
STARTUP & PRESCAL mask in ADC_MR.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
As use the multiple compatible string, we can remove hardware register in dt.
CC: devicetree@vger.kernel.org
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
