Hi Simon, On 01.02.2021 21:38, Simon Glass wrote: > On Tue, 26 Jan 2021 at 06:03, Heinrich Schuchardt <xypron.g...@gmx.de> wrote: >> On 26.01.21 12:25, Marek Szyprowski wrote: >>> On 26.01.2021 12:10, Heinrich Schuchardt wrote: >>>> On 1/26/21 10:50 AM, Marek Szyprowski wrote: >>>>> Add a simple Analog to Digital Converter device based button driver. >>>>> This >>>>> driver binds to the 'adc-keys' device tree node. >>>>> >>>>> Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com> >>>>> --- >>>>> drivers/button/Kconfig | 8 ++ >>>>> drivers/button/Makefile | 1 + >>>>> drivers/button/button-adc.c | 156 ++++++++++++++++++++++++++++++++++++ >>>>> 3 files changed, 165 insertions(+) >>>>> create mode 100644 drivers/button/button-adc.c >>>>> >>>>> diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig >>>>> index 6b3ec7e55d..6db3c5e93a 100644 >>>>> --- a/drivers/button/Kconfig >>>>> +++ b/drivers/button/Kconfig >>>>> @@ -9,6 +9,14 @@ config BUTTON >>>>> can provide access to board-specific buttons. Use of the >>>>> device tree >>>>> for configuration is encouraged. >>>>> >>>>> +config BUTTON_ADC >>>>> + bool "Button adc" >>>>> + depends on BUTTON >>>>> + help >>>>> + Enable support for buttons which are connected to Analog to >>>>> Digital >>>>> + Converter device. The ADC driver must use driver model. >>>>> Buttons are >>>>> + configured using the device tree. >>>>> + >>>>> config BUTTON_GPIO >>>>> bool "Button gpio" >>>>> depends on BUTTON >>>>> diff --git a/drivers/button/Makefile b/drivers/button/Makefile >>>>> index fcc10ebe8d..bbd18af149 100644 >>>>> --- a/drivers/button/Makefile >>>>> +++ b/drivers/button/Makefile >>>>> @@ -3,4 +3,5 @@ >>>>> # Copyright (C) 2020 Philippe Reynes <philippe.rey...@softathome.com> >>>>> >>>>> obj-$(CONFIG_BUTTON) += button-uclass.o >>>>> +obj-$(CONFIG_BUTTON_ADC) += button-adc.o >>>>> obj-$(CONFIG_BUTTON_GPIO) += button-gpio.o >>>>> diff --git a/drivers/button/button-adc.c b/drivers/button/button-adc.c >>>>> new file mode 100644 >>>>> index 0000000000..1901d59a0e >>>>> --- /dev/null >>>>> +++ b/drivers/button/button-adc.c >>>>> @@ -0,0 +1,156 @@ >>>>> +// SPDX-License-Identifier: GPL-2.0 >>>>> +/* >>>>> + * Copyright (C) 2021 Samsung Electronics Co., Ltd. >>>>> + * http://www.samsung.com >>>>> + * Author: Marek Szyprowski <m.szyprow...@samsung.com> >>>>> + */ >>>>> + >>>>> +#include <common.h> >>>>> +#include <adc.h> >>>>> +#include <button.h> >>>>> +#include <log.h> >>>>> +#include <dm.h> >>>>> +#include <dm/lists.h> >>>>> +#include <dm/of_access.h> >>>>> +#include <dm/uclass-internal.h> >>>>> + >>>>> +/** >>>>> + * struct button_adc_priv - private data for button-adc driver. >>>>> + * >>>>> + * @adc: Analog to Digital Converter device to which button is >>>>> connected. >>>>> + * @channel: channel of the ADC device to probe the button state. >>>>> + * @min: minimal raw ADC sample value to consider button as pressed. >>>>> + * @max: maximal raw ADC sample value to consider button as pressed. >>>>> + */ >>>>> +struct button_adc_priv { >>>>> + struct udevice *adc; >>>>> + int channel; >>>>> + int min; >>>>> + int max; >>>>> +}; >>>>> + >>>>> +static enum button_state_t button_adc_get_state(struct udevice *dev) >>>>> +{ >>>>> + struct button_adc_priv *priv = dev_get_priv(dev); >>>>> + unsigned int val; >>>>> + int ret; >>>>> + >>>>> + ret = adc_start_channel(priv->adc, priv->channel); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + ret = adc_channel_data(priv->adc, priv->channel, &val); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + if (ret == 0) >>>>> + return (val >= priv->min && val < priv->max) ? >>>>> + BUTTON_ON : BUTTON_OFF; >>>>> + >>>>> + return ret; >>>>> +} >>>>> + >>>>> +static int button_adc_probe(struct udevice *dev) >>>>> +{ >>>>> + struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev); >>>>> + struct button_adc_priv *priv = dev_get_priv(dev); >>>>> + struct ofnode_phandle_args args; >>>>> + u32 treshold, up_treshold, t; >>>>> + unsigned int mask; >>>>> + ofnode node; >>>>> + int ret, vdd; >>>>> + >>>>> + /* Ignore the top-level button node */ >>>>> + if (!uc_plat->label) >>>>> + return 0; >>>>> + >>>>> + ret = dev_read_phandle_with_args(dev->parent, "io-channels", >>>>> + "#io-channel-cells", 0, 0, &args); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + ret = uclass_get_device_by_ofnode(UCLASS_ADC, args.node, >>>>> &priv->adc); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + ret = ofnode_read_u32(dev_ofnode(dev->parent), >>>>> + "keyup-threshold-microvolt", &up_treshold); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + ret = ofnode_read_u32(dev_ofnode(dev), "press-threshold-microvolt", >>>>> + &treshold); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + dev_for_each_subnode(node, dev->parent) { >>>>> + ret = ofnode_read_u32(dev_ofnode(dev), >>>>> + "press-threshold-microvolt", &t); >>>>> + if (ret) >>>>> + return ret; >>>>> + >>>>> + if (t > treshold) >>>>> + up_treshold = t; >>>> Linux' Documentation/devicetree/bindings/input/adc-keys.txt describes >>>> that one virtual key is created per sub-node. >>>> >>>> If I read your code correctly, this is not what you are implementing. >>>> Instead you only define a single key per adc-keys node. >>>> >>>> Why are your deviating from the bindings document? >>> No I don't. button_adc_bind() binds to the root node with 'adc-keys' >>> compatible, while the dev_for_each_subnode() loop instantiates driver >>> for each subnode, so the button_adc_probe() is called for each defined >>> key. I've copied this pattern from gpio-keys driver. >>> >>> >> ... >>> >>> Here is the related code: >> Thanks for pointing this out. >> >> To really test the driver we would need an emulated device on the >> sandbox where we can set the voltage and see which button is activated. >> >> I assume this can be added to test/dm/adc.c. > Yes please!
Could you give me a bit more hints or point where to start? I've tried to build sandbox, but it fails for v2021.01 release (I've did make sandbox_defconfig && make all). I assume I would need to add adc and adc-keys devices to some sandbox dts and some code triggering and checking the key values, but that's all I know now. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland