Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Copyright (C) 2021 Samsung Electronics Co., Ltd. |
| 4 | * http://www.samsung.com |
| 5 | * Author: Marek Szyprowski <m.szyprowski@samsung.com> |
| 6 | */ |
| 7 | |
| 8 | #include <common.h> |
| 9 | #include <adc.h> |
| 10 | #include <button.h> |
| 11 | #include <log.h> |
| 12 | #include <dm.h> |
| 13 | #include <dm/lists.h> |
| 14 | #include <dm/of_access.h> |
| 15 | #include <dm/uclass-internal.h> |
| 16 | |
| 17 | /** |
| 18 | * struct button_adc_priv - private data for button-adc driver. |
| 19 | * |
| 20 | * @adc: Analog to Digital Converter device to which button is connected. |
| 21 | * @channel: channel of the ADC device to probe the button state. |
| 22 | * @min: minimal uV value to consider button as pressed. |
| 23 | * @max: maximal uV value to consider button as pressed. |
| 24 | */ |
| 25 | struct button_adc_priv { |
| 26 | struct udevice *adc; |
| 27 | int channel; |
| 28 | int min; |
| 29 | int max; |
| 30 | }; |
| 31 | |
| 32 | static enum button_state_t button_adc_get_state(struct udevice *dev) |
| 33 | { |
| 34 | struct button_adc_priv *priv = dev_get_priv(dev); |
| 35 | unsigned int val; |
| 36 | int ret, uV; |
| 37 | |
| 38 | ret = adc_start_channel(priv->adc, priv->channel); |
| 39 | if (ret) |
| 40 | return ret; |
| 41 | |
| 42 | ret = adc_channel_data(priv->adc, priv->channel, &val); |
| 43 | if (ret) |
| 44 | return ret; |
| 45 | |
| 46 | ret = adc_raw_to_uV(priv->adc, val, &uV); |
| 47 | if (ret) |
| 48 | return ret; |
| 49 | |
| 50 | return (uV >= priv->min && uV < priv->max) ? BUTTON_ON : BUTTON_OFF; |
| 51 | } |
| 52 | |
| 53 | static int button_adc_of_to_plat(struct udevice *dev) |
| 54 | { |
| 55 | struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev); |
| 56 | struct button_adc_priv *priv = dev_get_priv(dev); |
| 57 | struct ofnode_phandle_args args; |
Neil Armstrong | efe1f06 | 2021-02-23 16:07:51 +0100 | [diff] [blame] | 58 | u32 threshold, up_threshold, t; |
Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 59 | ofnode node; |
| 60 | int ret; |
| 61 | |
| 62 | /* Ignore the top-level button node */ |
| 63 | if (!uc_plat->label) |
| 64 | return 0; |
| 65 | |
| 66 | ret = dev_read_phandle_with_args(dev->parent, "io-channels", |
| 67 | "#io-channel-cells", 0, 0, &args); |
| 68 | if (ret) |
| 69 | return ret; |
| 70 | |
| 71 | ret = uclass_get_device_by_ofnode(UCLASS_ADC, args.node, &priv->adc); |
| 72 | if (ret) |
| 73 | return ret; |
| 74 | |
| 75 | ret = ofnode_read_u32(dev_ofnode(dev->parent), |
Neil Armstrong | efe1f06 | 2021-02-23 16:07:51 +0100 | [diff] [blame] | 76 | "keyup-threshold-microvolt", &up_threshold); |
Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 77 | if (ret) |
| 78 | return ret; |
| 79 | |
| 80 | ret = ofnode_read_u32(dev_ofnode(dev), "press-threshold-microvolt", |
Neil Armstrong | efe1f06 | 2021-02-23 16:07:51 +0100 | [diff] [blame] | 81 | &threshold); |
Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 82 | if (ret) |
| 83 | return ret; |
| 84 | |
| 85 | dev_for_each_subnode(node, dev->parent) { |
| 86 | ret = ofnode_read_u32(node, "press-threshold-microvolt", &t); |
| 87 | if (ret) |
| 88 | return ret; |
| 89 | |
Neil Armstrong | efe1f06 | 2021-02-23 16:07:51 +0100 | [diff] [blame] | 90 | if (t > threshold) |
| 91 | up_threshold = t; |
Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 92 | } |
| 93 | |
| 94 | priv->channel = args.args[0]; |
Neil Armstrong | efe1f06 | 2021-02-23 16:07:51 +0100 | [diff] [blame] | 95 | priv->min = threshold; |
| 96 | priv->max = up_threshold; |
Marek Szyprowski | c0165c8 | 2021-02-18 11:33:15 +0100 | [diff] [blame] | 97 | |
| 98 | return ret; |
| 99 | } |
| 100 | |
| 101 | static int button_adc_bind(struct udevice *parent) |
| 102 | { |
| 103 | struct udevice *dev; |
| 104 | ofnode node; |
| 105 | int ret; |
| 106 | |
| 107 | dev_for_each_subnode(node, parent) { |
| 108 | struct button_uc_plat *uc_plat; |
| 109 | const char *label; |
| 110 | |
| 111 | label = ofnode_read_string(node, "label"); |
| 112 | if (!label) { |
| 113 | debug("%s: node %s has no label\n", __func__, |
| 114 | ofnode_get_name(node)); |
| 115 | return -EINVAL; |
| 116 | } |
| 117 | ret = device_bind_driver_to_node(parent, "button_adc", |
| 118 | ofnode_get_name(node), |
| 119 | node, &dev); |
| 120 | if (ret) |
| 121 | return ret; |
| 122 | uc_plat = dev_get_uclass_plat(dev); |
| 123 | uc_plat->label = label; |
| 124 | } |
| 125 | |
| 126 | return 0; |
| 127 | } |
| 128 | |
| 129 | static const struct button_ops button_adc_ops = { |
| 130 | .get_state = button_adc_get_state, |
| 131 | }; |
| 132 | |
| 133 | static const struct udevice_id button_adc_ids[] = { |
| 134 | { .compatible = "adc-keys" }, |
| 135 | { } |
| 136 | }; |
| 137 | |
| 138 | U_BOOT_DRIVER(button_adc) = { |
| 139 | .name = "button_adc", |
| 140 | .id = UCLASS_BUTTON, |
| 141 | .of_match = button_adc_ids, |
| 142 | .ops = &button_adc_ops, |
| 143 | .priv_auto = sizeof(struct button_adc_priv), |
| 144 | .bind = button_adc_bind, |
| 145 | .of_to_plat = button_adc_of_to_plat, |
| 146 | }; |