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: >> +static int button_adc_bind(struct udevice *parent) >> +{ >> + struct udevice *dev; >> + ofnode node; >> + int ret; >> + >> + dev_for_each_subnode(node, parent) { >> + struct button_uc_plat *uc_plat; >> + const char *label; >> + >> + label = ofnode_read_string(node, "label"); >> + if (!label) { >> + debug("%s: node %s has no label\n", __func__, >> + ofnode_get_name(node)); >> + return -EINVAL; >> + } >> + ret = device_bind_driver_to_node(parent, "button_adc", >> + ofnode_get_name(node), >> + node, &dev); >> + if (ret) >> + return ret; >> + uc_plat = dev_get_uclass_plat(dev); >> + uc_plat->label = label; >> + } >> + >> + return 0; >> +} >> + >> +static const struct button_ops button_adc_ops = { >> + .get_state = button_adc_get_state, >> +}; >> + >> +static const struct udevice_id button_adc_ids[] = { >> + { .compatible = "adc-keys" }, >> + { } >> +}; >> + >> +U_BOOT_DRIVER(button_adc) = { >> + .name = "button_adc", >> + .id = UCLASS_BUTTON, >> + .of_match = button_adc_ids, >> + .ops = &button_adc_ops, >> + .priv_auto = sizeof(struct button_adc_priv), >> + .bind = button_adc_bind, >> + .probe = button_adc_probe, >> +}; >> > > Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland