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- // 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 threshold, up_threshold, 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_threshold);
- if (ret)
- return ret;
- ret = ofnode_read_u32(dev_ofnode(dev), "press-threshold-microvolt",
- &threshold);
- 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 > threshold)
- up_threshold = t;
- }
- priv->channel = args.args[0];
- priv->min = threshold;
- priv->max = up_threshold;
- 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,
- };
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