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Date:   Mon, 02 May 2022 19:15:01 +0800
From:   Icenowy Zheng <icenowy@aosc.io>
To:     Maxime Ripard <maxime@cerno.tech>, Ruslan Zalata <rz@fabmicro.ru>
CC:     Guenter Roeck <linux@roeck-us.net>,
        Jean Delvare <jdelvare@suse.com>, Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev
Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v2=5D_hwmon=3A_=28sun4i-lradc=29_Add_dri?= =?US-ASCII?Q?ver_for_LRADC_found_on_Allwinner_A13/A20_SoC?=
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=E4=BA=8E 2022=E5=B9=B45=E6=9C=882=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=887:=
00:10, Maxime Ripard <maxime@cerno=2Etech> =E5=86=99=E5=88=B0:
>Hi,
>
>On Thu, Apr 28, 2022 at 09:09:03PM +0000, Ruslan Zalata wrote:
>> Some Allwinner SoCs like A13, A20 or T2 are equipped with two-channel
>> low rate (6 bit) ADC that is often used for extra keys=2E There's a dri=
ver
>> for that already implementing standard input device, but it has these
>> limitations: 1) it cannot be used for general ADC data equisition, and
>> 2) it uses only one LRADC channel of two available=2E
>>=20
>> This driver provides basic hwmon interface to both channels of LRADC on
>> such Allwinner SoCs=2E
>>=20
>> Signed-off-by: Ruslan Zalata <rz@fabmicro=2Eru>
>> ---
>>  MAINTAINERS                       |   6 +
>>  drivers/hwmon/Kconfig             |  13 ++
>>  drivers/hwmon/Makefile            |   1 +
>>  drivers/hwmon/sun4i-lradc-hwmon=2Ec | 280 ++++++++++++++++++++++++++++=
++
>>  4 files changed, 300 insertions(+)
>>  create mode 100644 drivers/hwmon/sun4i-lradc-hwmon=2Ec
>>=20
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 5e8c2f61176=2E=2Ed9c71e94133 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -18861,6 +18861,12 @@ S:	Maintained
>>  F:	Documentation/devicetree/bindings/input/allwinner,sun4i-a10-lradc-k=
eys=2Eyaml
>>  F:	drivers/input/keyboard/sun4i-lradc-keys=2Ec
>> =20
>> +SUN4I LOW RES ADC HWMON DRIVER
>> +M:	Ruslan Zalata <rz@fabmicro=2Eru>
>> +L:	linux-hwmon@vger=2Ekernel=2Eorg
>> +S:	Maintained
>> +F:	drivers/hwmon/sun4i-lradc-hwmon=2Ec
>> +
>>  SUNDANCE NETWORK DRIVER
>>  M:	Denis Kirjanov <kda@linux-powerpc=2Eorg>
>>  L:	netdev@vger=2Ekernel=2Eorg
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 68a8a27ab3b=2E=2E86776488a81 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -1691,6 +1691,19 @@ config SENSORS_SIS5595
>>  	  This driver can also be built as a module=2E If so, the module
>>  	  will be called sis5595=2E
>> =20
>> +config SENSORS_SUN4I_LRADC
>> +	tristate "Allwinner A13/A20 LRADC hwmon"
>> +	depends on ARCH_SUNXI && !KEYBOARD_SUN4I_LRADC
>> +	help
>> +	  Say y here to support the LRADC found in Allwinner A13/A20 SoCs=2E
>> +	  Both channels are supported=2E
>> +
>> +	  This driver can also be built as module=2E If so, the module
>> +	  will be called sun4i-lradc-hwmon=2E
>> +
>> +	  This option is not compatible with KEYBOARD_SUN4I_LRADC, one
>> +	  of these must be used at a time=2E
>
>How do you plan on enforcing that?
>
>I guess a better path forward would be to either register an hwmon
>device in the original driver, or convert that driver to iio and use
>iio-hwmon=2E

I think this driver should be use IIO, and then try to probe an IIO input
if possible=2E

>
>Maxime