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@@ -0,0 +1,146 @@
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+// SPDX-License-Identifier: GPL-2.0
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+/*
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+ * Copyright (C) 2021 Samsung Electronics Co., Ltd.
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+ * http://www.samsung.com
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+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
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+ */
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+
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+#include <common.h>
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+#include <adc.h>
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+#include <button.h>
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+#include <log.h>
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+#include <dm.h>
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+#include <dm/lists.h>
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+#include <dm/of_access.h>
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+#include <dm/uclass-internal.h>
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+
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+/**
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+ * struct button_adc_priv - private data for button-adc driver.
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+ *
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+ * @adc: Analog to Digital Converter device to which button is connected.
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+ * @channel: channel of the ADC device to probe the button state.
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+ * @min: minimal uV value to consider button as pressed.
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+ * @max: maximal uV value to consider button as pressed.
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+ */
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+struct button_adc_priv {
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+ struct udevice *adc;
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+ int channel;
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+ int min;
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+ int max;
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+};
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+
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+static enum button_state_t button_adc_get_state(struct udevice *dev)
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+{
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+ struct button_adc_priv *priv = dev_get_priv(dev);
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+ unsigned int val;
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+ int ret, uV;
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+
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+ ret = adc_start_channel(priv->adc, priv->channel);
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+ if (ret)
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+ return ret;
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+
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+ ret = adc_channel_data(priv->adc, priv->channel, &val);
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+ if (ret)
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+ return ret;
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+
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+ ret = adc_raw_to_uV(priv->adc, val, &uV);
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+ if (ret)
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+ return ret;
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+
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+ return (uV >= priv->min && uV < priv->max) ? BUTTON_ON : BUTTON_OFF;
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+}
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+
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+static int button_adc_of_to_plat(struct udevice *dev)
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+{
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+ struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev);
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+ struct button_adc_priv *priv = dev_get_priv(dev);
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+ struct ofnode_phandle_args args;
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+ u32 treshold, up_treshold, t;
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+ ofnode node;
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+ int ret;
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+
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+ /* Ignore the top-level button node */
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+ if (!uc_plat->label)
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+ return 0;
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+
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+ ret = dev_read_phandle_with_args(dev->parent, "io-channels",
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+ "#io-channel-cells", 0, 0, &args);
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+ if (ret)
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+ return ret;
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+
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+ ret = uclass_get_device_by_ofnode(UCLASS_ADC, args.node, &priv->adc);
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+ if (ret)
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+ return ret;
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+
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+ ret = ofnode_read_u32(dev_ofnode(dev->parent),
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+ "keyup-threshold-microvolt", &up_treshold);
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+ if (ret)
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+ return ret;
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+
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+ ret = ofnode_read_u32(dev_ofnode(dev), "press-threshold-microvolt",
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+ &treshold);
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+ if (ret)
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+ return ret;
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+
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+ dev_for_each_subnode(node, dev->parent) {
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+ ret = ofnode_read_u32(node, "press-threshold-microvolt", &t);
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+ if (ret)
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+ return ret;
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+
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+ if (t > treshold)
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+ up_treshold = t;
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+ }
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+
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+ priv->channel = args.args[0];
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+ priv->min = treshold;
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+ priv->max = up_treshold;
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+
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+ return ret;
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+}
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+
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+static int button_adc_bind(struct udevice *parent)
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+{
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+ struct udevice *dev;
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+ ofnode node;
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+ int ret;
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+
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+ dev_for_each_subnode(node, parent) {
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+ struct button_uc_plat *uc_plat;
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+ const char *label;
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+
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+ label = ofnode_read_string(node, "label");
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+ if (!label) {
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+ debug("%s: node %s has no label\n", __func__,
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+ ofnode_get_name(node));
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+ return -EINVAL;
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+ }
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+ ret = device_bind_driver_to_node(parent, "button_adc",
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+ ofnode_get_name(node),
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+ node, &dev);
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+ if (ret)
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+ return ret;
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+ uc_plat = dev_get_uclass_plat(dev);
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+ uc_plat->label = label;
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+ }
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+
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+ return 0;
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+}
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+
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+static const struct button_ops button_adc_ops = {
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+ .get_state = button_adc_get_state,
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+};
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+
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+static const struct udevice_id button_adc_ids[] = {
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+ { .compatible = "adc-keys" },
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+ { }
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+};
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+
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+U_BOOT_DRIVER(button_adc) = {
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+ .name = "button_adc",
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+ .id = UCLASS_BUTTON,
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+ .of_match = button_adc_ids,
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+ .ops = &button_adc_ops,
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+ .priv_auto = sizeof(struct button_adc_priv),
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+ .bind = button_adc_bind,
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+ .of_to_plat = button_adc_of_to_plat,
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+};
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