On Mon, May 02, 2022 at 07:15:01PM +0800, Icenowy Zheng wrote: > > > 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. It's been a while, but if I remember well we couldn't use IIO for that driver because it's not generating interrupts all the time but only when it goes over a given threshold: https://lore.kernel.org/all/52C5E9F1.9010700@xxxxxxxxxx/ I'm not sure if it's still relevant, so we might just need to add an hwmon driver to the existing driver Maxime
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