Re: [PATCH v2] hwmon: (sun4i-lradc) Add driver for LRADC found on Allwinner A13/A20 SoC

[Icenowy Zheng]

于 2022年5月2日 GMT+08:00 下午7:00:10, Maxime Ripard <maxime@xxxxxxxxxx> 写到:
>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. There's a driver
>> 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.
>> 
>> This driver provides basic hwmon interface to both channels of LRADC on
>> such Allwinner SoCs.
>> 
>> Signed-off-by: Ruslan Zalata <rz@xxxxxxxxxxx>
>> ---
>>  MAINTAINERS                       |   6 +
>>  drivers/hwmon/Kconfig             |  13 ++
>>  drivers/hwmon/Makefile            |   1 +
>>  drivers/hwmon/sun4i-lradc-hwmon.c | 280 ++++++++++++++++++++++++++++++
>>  4 files changed, 300 insertions(+)
>>  create mode 100644 drivers/hwmon/sun4i-lradc-hwmon.c
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 5e8c2f61176..d9c71e94133 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -18861,6 +18861,12 @@ S:	Maintained
>>  F:	Documentation/devicetree/bindings/input/allwinner,sun4i-a10-lradc-keys.yaml
>>  F:	drivers/input/keyboard/sun4i-lradc-keys.c
>>  
>> +SUN4I LOW RES ADC HWMON DRIVER
>> +M:	Ruslan Zalata <rz@xxxxxxxxxxx>
>> +L:	linux-hwmon@xxxxxxxxxxxxxxx
>> +S:	Maintained
>> +F:	drivers/hwmon/sun4i-lradc-hwmon.c
>> +
>>  SUNDANCE NETWORK DRIVER
>>  M:	Denis Kirjanov <kda@xxxxxxxxxxxxxxxxx>
>>  L:	netdev@xxxxxxxxxxxxxxx
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 68a8a27ab3b..86776488a81 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. If so, the module
>>  	  will be called sis5595.
>>  
>> +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.
>> +	  Both channels are supported.
>> +
>> +	  This driver can also be built as module. If so, the module
>> +	  will be called sun4i-lradc-hwmon.
>> +
>> +	  This option is not compatible with KEYBOARD_SUN4I_LRADC, one
>> +	  of these must be used at a time.
>
>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.

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

>
>Maxime