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Subject: Re: [PATCH v7 0/9] Add support for SAMA5D2 touchscreen
To:     Jonathan Cameron <jic23@kernel.org>
CC:     <ludovic.desroches@microchip.com>, <alexandre.belloni@bootlin.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-iio@vger.kernel.org>, <linux-input@vger.kernel.org>,
        <nicolas.ferre@microchip.com>, <dmitry.torokhov@gmail.com>,
        <robh@kernel.org>
References: <1526975559-18966-1-git-send-email-eugen.hristev@microchip.com>
 <20180522185732.0336d29c@archlinux>
From:   Eugen Hristev <eugen.hristev@microchip.com>
Message-ID: <45ff713b-7811-22c6-2124-4fbcad59b7e8@microchip.com>
Date:   Mon, 4 Jun 2018 09:15:57 +0300
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On 22.05.2018 20:57, Jonathan Cameron wrote:
> On Tue, 22 May 2018 10:52:30 +0300
> Eugen Hristev <eugen.hristev@microchip.com> wrote:
> 
>> Hello,
>>
>> This patch series is a rework of my previous series named:
>> [PATCH 00/14] iio: triggers: add consumer support
>>
>> This is the version 7 of the series, and addresses the received feedback
>> on the v2 series named:
>> [PATCH v2 00/10]  Add support for SAMA5D2 touchscreen
>> and the v3 series named
>> [PATCH v3 00/11]  Add support for SAMA5D2 touchscreen
>> and the v4 series named
>> [PATCH v4 0/9]  Add support for SAMA5D2 touchscreen
>> and fixes one bug found in series named
>> [PATCH v5 0/9]  Add support for SAMA5D2 touchscreen
>> and addresses comments in series named
>> [PATCH v6 0/9]  Add support for SAMA5D2 touchscreen
>>
>> This series applies on top of fixes-togreg branch of iio.git,
>> specifically on top of commit:
>> "f0c8d1f" : iio: adc: at91-sama5d2_adc:
>>   fix channel configuration for differential channels
>>
>> Jonathan, if you need me to rebase this on top of testing, let me know.
>>
>> Changes in previous versions are presented at the end of the cover letter below.
>> Thanks everyone for the feedback. Below is the original v2 cover letter:
>>
>> In few words, this is the implementation of splitting the functionality
>> of the IP block ADC device in SAMA5D2 SoC from ADC with touchscreen
>> support. In order to avoid having a MFD device, two separate
>> drivers that would work on same register base and split the IRQ,etc,
>> as advised on the mailing list, I created a consumer driver for the
>> channels, that will connect to the ADC as described in the device tree.
>>
>> I have collected feedback from everyone and here is the result:
>> I have added a new generic resistive touchscreen driver, which acts
>> as a iio consumer for the given channels and will create an input
>> device and report the events. It uses a callback buffer to register
>> to the IIO device and waits for data to be pushed.
>> Inside the IIO device, I have kept a similar approach with the first version
>> of the series, except that now the driver can take multiple buffers, and
>> will configure the touchscreen part of the hardware device if the specific
>> channels are requested.
>>
>> The SAMA5D2 ADC driver registers three new channels: two for the
>> position on the X and Y axis, and one for the touch pressure.
>> When channels are requested, it will check if the touchscreen channel mask
>> includes the requested channels (it is possible that the consumer driver
>> will not request pressure for example). If it's the case, it will work
>> in touchscreen mode, and will refuse to do usual analog-digital conversion,
>> because we have a single trigger and the touchscreen needs it.
>> When the scan mask will include only old channels, the driver will function
>> in the same way as before. If the scan mask somehow is a mix of the two (the
>> masks intersect), the driver will refuse to work whatsoever (cannot have both
>> in the same time).
>> The driver allows reading raw data for the new channels, if claim direct
>> mode works: no touchscreen driver requested anything. The new channels can
>> act like the old ones. However, when requesting these channels, the usual
>> trigger will not work and will not be enabled. The touchscreen channels
>> require special trigger and irq configuration: pen detect, no pen detect
>> and a periodic trigger to sample the touchscreen position and pressure.
>> If the user attempts to use another trigger while there is a buffer
>> that already requested the touchscreen channels (thus the trigger), the
>> driver will refuse to comply.
>>
>> In order to have defines for the channel numbers, I added a bindings include
>> file that goes on a separate commit :
>> dt-bindings: iio: adc: at91-sama5d2_adc: add channel specific consumer info
>> This should go in the same tree with the following commits :
>>    ARM: dts: at91: sama5d2: add channel cells for ADC device
>>    ARM: dts: at91: sama5d2: Add resistive touch device
>>
>> as build will break because these commits depend on the binding one
>> which creates the included header file.
>> V5 update: After discussing with Alexandre Belloni on Mailing list, the two
>> DTS patches are to be taken in the next version after bindings reach mainline.
>>
>> Changes in v7:
>>   - Addressed some feedback from Dmitry, explained in input driver patch
>> changelog.
>>   - Added Acked-by Dmitry.
>>
>> Changes in v6:
>>   - Fixed a crash in ADC driver , explained in driver patch changelog.
>>   - changed a dev_err to dev_dbg in input driver.
>>   - added Reviewed-by Rob Herring.
>>
>> Changes in v5:
>>   - renamed property touchscreen-threshold-pressure to touchscreen-min-pressure
>>   - added one return in touchscreen driver
>>
>> Changes in v4:
>>   - removed patch for inkern module get/set kref
>>   - addressed feedback on both the ADC and the touchscreen driver. each
>> patch has a history inside the patch file for the specific changes.
>>   - patch that fixes the channel fix
>> [PATCH v3 01/11] iio: adc: at91-sama5d2_adc:
>>   fix channel configuration for differential channels
>> was accepted in fixes-togreg branch thus removed from this series.
>>   - added Reviewed-by for the bindings by Rob Herring
>>
>> Changes in v3:
>>   - changed input driver name according to feedback and reworked in commits
>> to adapt to binding changes and new name.
>>   - moved channel index fix in at91-sama5d2_adc at the beginning of the series
>> (PATCH 01/11)
>>   - created a new optional binding for the touchscreen as a separate commit
>> and added it to the series :
>>   [PATCH v3 04/11] dt-bindings: input: touchscreen: add pressure
>>   threshold touchscreen property
>>   - changed at91-sama5d2_adc driver patch to address the comments. Exact changes
>> are in the patch file for the driver source file.
>>
>> Eugen Hristev (9):
>>    MAINTAINERS: add generic resistive touchscreen adc
>>    iio: Add channel for Position Relative
>>    dt-bindings: input: touchscreen: add minimum pressure touchscreen
>>      property
>>    dt-bindings: input: touchscreen: resistive-adc-touch: create bindings
>>    iio: adc: at91-sama5d2_adc: add support for position and pressure
>>      channels
>>    input: touchscreen: resistive-adc-touch: add generic resistive ADC
>>      touchscreen
>>    dt-bindings: iio: adc: at91-sama5d2_adc: add channel specific consumer
>>      info
>>    ARM: dts: at91: sama5d2: add channel cells for ADC device
>>    ARM: dts: at91: sama5d2: Add resistive touch device
>>
>>   Documentation/ABI/testing/sysfs-bus-iio            |  12 +
>>   .../bindings/iio/adc/at91-sama5d2_adc.txt          |   9 +
>>   .../input/touchscreen/resistive-adc-touch.txt      |  30 +
>>   .../bindings/input/touchscreen/touchscreen.txt     |   3 +
>>   MAINTAINERS                                        |   6 +
>>   arch/arm/boot/dts/sama5d2.dtsi                     |  12 +
>>   drivers/iio/adc/at91-sama5d2_adc.c                 | 609 +++++++++++++++++++--
>>   drivers/iio/industrialio-core.c                    |   1 +
>>   drivers/input/touchscreen/Kconfig                  |  13 +
>>   drivers/input/touchscreen/Makefile                 |   1 +
>>   drivers/input/touchscreen/resistive-adc-touch.c    | 204 +++++++
>>   include/dt-bindings/iio/adc/at91-sama5d2_adc.h     |  16 +
>>   include/uapi/linux/iio/types.h                     |   1 +
>>   tools/iio/iio_event_monitor.c                      |   2 +
>>   14 files changed, 861 insertions(+), 58 deletions(-)
>>   create mode 100644 Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt
>>   create mode 100644 drivers/input/touchscreen/resistive-adc-touch.c
>>   create mode 100644 include/dt-bindings/iio/adc/at91-sama5d2_adc.h
>>
> 
> Hi All,
> 
> I'm happy to take this, but there is a slight issue that we have a fix working
> it's way in which this is dependent on.
> 
> I'll see if we can get this sorted before the merge window, but we may be
> cutting it fine.
> 
> Jonathan
> 

Hello Jonathan,

I can see the dependency fix made it to 4.17. What is the plan for this 
series? Getting into this merge window ?

Thanks,
Eugen