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.szyprowski@samsung.com Reviewed-by: Simon Glass sjg@chromium.org --- drivers/button/Kconfig | 8 ++ drivers/button/Makefile | 1 + drivers/button/button-adc.c | 146 ++++++++++++++++++++++++++++++++++++ 3 files changed, 155 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.reynes@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..eed86564fb --- /dev/null +++ b/drivers/button/button-adc.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Samsung Electronics Co., Ltd. + * http://www.samsung.com + * Author: Marek Szyprowski m.szyprowski@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 uV value to consider button as pressed. + * @max: maximal uV 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, uV; + + 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; + + ret = adc_raw_to_uV(priv->adc, val, &uV); + if (ret) + return ret; + + return (uV >= priv->min && uV < priv->max) ? BUTTON_ON : BUTTON_OFF; +} + +static int button_adc_of_to_plat(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; + ofnode node; + int ret; + + /* 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(node, "press-threshold-microvolt", &t); + if (ret) + return ret; + + if (t > treshold) + up_treshold = t; + } + + priv->channel = args.args[0]; + priv->min = treshold; + priv->max = up_treshold; + + return ret; +} + +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, + .of_to_plat = button_adc_of_to_plat, +};