1// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later
2/*
3 * Dell Wyse 3020 a.k.a. "Ariel" Power Button Driver
4 *
5 * Copyright (C) 2020 Lubomir Rintel
6 */
7
8#include <linux/device.h>
9#include <linux/gfp.h>
10#include <linux/input.h>
11#include <linux/interrupt.h>
12#include <linux/mod_devicetable.h>
13#include <linux/module.h>
14#include <linux/spi/spi.h>
15
16#define RESP_COUNTER(response) (response.header & 0x3)
17#define RESP_SIZE(response) ((response.header >> 2) & 0x3)
18#define RESP_TYPE(response) ((response.header >> 4) & 0xf)
19
20struct ec_input_response {
21 u8 reserved;
22 u8 header;
23 u8 data[3];
24} __packed;
25
26struct ariel_pwrbutton {
27 struct spi_device *client;
28 struct input_dev *input;
29 u8 msg_counter;
30};
31
32static int ec_input_read(struct ariel_pwrbutton *priv,
33 struct ec_input_response *response)
34{
35 u8 read_request[] = { 0x00, 0x5a, 0xa5, 0x00, 0x00 };
36 struct spi_device *spi = priv->client;
37 struct spi_transfer t = {
38 .tx_buf = read_request,
39 .rx_buf = response,
40 .len = sizeof(read_request),
41 };
42
43 compiletime_assert(sizeof(read_request) == sizeof(*response),
44 "SPI xfer request/response size mismatch");
45
46 return spi_sync_transfer(spi, xfers: &t, num_xfers: 1);
47}
48
49static irqreturn_t ec_input_interrupt(int irq, void *dev_id)
50{
51 struct ariel_pwrbutton *priv = dev_id;
52 struct spi_device *spi = priv->client;
53 struct ec_input_response response;
54 int error;
55 int i;
56
57 error = ec_input_read(priv, response: &response);
58 if (error < 0) {
59 dev_err(&spi->dev, "EC read failed: %d\n", error);
60 goto out;
61 }
62
63 if (priv->msg_counter == RESP_COUNTER(response)) {
64 dev_warn(&spi->dev, "No new data to read?\n");
65 goto out;
66 }
67
68 priv->msg_counter = RESP_COUNTER(response);
69
70 if (RESP_TYPE(response) != 0x3 && RESP_TYPE(response) != 0xc) {
71 dev_dbg(&spi->dev, "Ignoring message that's not kbd data\n");
72 goto out;
73 }
74
75 for (i = 0; i < RESP_SIZE(response); i++) {
76 switch (response.data[i]) {
77 case 0x74:
78 input_report_key(dev: priv->input, KEY_POWER, value: 1);
79 input_sync(dev: priv->input);
80 break;
81 case 0xf4:
82 input_report_key(dev: priv->input, KEY_POWER, value: 0);
83 input_sync(dev: priv->input);
84 break;
85 default:
86 dev_dbg(&spi->dev, "Unknown scan code: %02x\n",
87 response.data[i]);
88 }
89 }
90
91out:
92 return IRQ_HANDLED;
93}
94
95static int ariel_pwrbutton_probe(struct spi_device *spi)
96{
97 struct ec_input_response response;
98 struct ariel_pwrbutton *priv;
99 int error;
100
101 if (!spi->irq) {
102 dev_err(&spi->dev, "Missing IRQ.\n");
103 return -EINVAL;
104 }
105
106 priv = devm_kzalloc(dev: &spi->dev, size: sizeof(*priv), GFP_KERNEL);
107 if (!priv)
108 return -ENOMEM;
109
110 priv->client = spi;
111 spi_set_drvdata(spi, data: priv);
112
113 priv->input = devm_input_allocate_device(&spi->dev);
114 if (!priv->input)
115 return -ENOMEM;
116 priv->input->name = "Power Button";
117 priv->input->dev.parent = &spi->dev;
118 input_set_capability(dev: priv->input, EV_KEY, KEY_POWER);
119 error = input_register_device(priv->input);
120 if (error) {
121 dev_err(&spi->dev, "error registering input device: %d\n", error);
122 return error;
123 }
124
125 error = ec_input_read(priv, response: &response);
126 if (error < 0) {
127 dev_err(&spi->dev, "EC read failed: %d\n", error);
128 return error;
129 }
130 priv->msg_counter = RESP_COUNTER(response);
131
132 error = devm_request_threaded_irq(dev: &spi->dev, irq: spi->irq, NULL,
133 thread_fn: ec_input_interrupt,
134 IRQF_ONESHOT,
135 devname: "Ariel EC Input", dev_id: priv);
136
137 if (error) {
138 dev_err(&spi->dev, "Failed to request IRQ %d: %d\n",
139 spi->irq, error);
140 return error;
141 }
142
143 return 0;
144}
145
146static const struct of_device_id ariel_pwrbutton_of_match[] = {
147 { .compatible = "dell,wyse-ariel-ec-input" },
148 { }
149};
150MODULE_DEVICE_TABLE(of, ariel_pwrbutton_of_match);
151
152static const struct spi_device_id ariel_pwrbutton_spi_ids[] = {
153 { .name = "wyse-ariel-ec-input" },
154 { }
155};
156MODULE_DEVICE_TABLE(spi, ariel_pwrbutton_spi_ids);
157
158static struct spi_driver ariel_pwrbutton_driver = {
159 .driver = {
160 .name = "dell-wyse-ariel-ec-input",
161 .of_match_table = ariel_pwrbutton_of_match,
162 },
163 .probe = ariel_pwrbutton_probe,
164 .id_table = ariel_pwrbutton_spi_ids,
165};
166module_spi_driver(ariel_pwrbutton_driver);
167
168MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
169MODULE_DESCRIPTION("Dell Wyse 3020 Power Button Input Driver");
170MODULE_LICENSE("Dual BSD/GPL");
171

source code of linux/drivers/input/misc/ariel-pwrbutton.c