Hi, On Tue, 26 Jan 2021 at 06:03, Heinrich Schuchardt <xypron.g...@gmx.de> wrote: > > On 26.01.21 12:25, Marek Szyprowski wrote: > > Hi Heinrich, > > > > 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! Regards, Simon