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 20 struct ec_input_response { 21 u8 reserved; 22 u8 header; 23 u8 data[3]; 24 } __packed; 25 26 struct ariel_pwrbutton { 27 struct spi_device *client; 28 struct input_dev *input; 29 u8 msg_counter; 30 }; 31 32 static 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, &t, 1); 47 } 48 49 static 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); 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(priv->input, KEY_POWER, 1); 79 input_sync(priv->input); 80 break; 81 case 0xf4: 82 input_report_key(priv->input, KEY_POWER, 0); 83 input_sync(priv->input); 84 break; 85 default: 86 dev_dbg(&spi->dev, "Unknown scan code: %02x\n", 87 response.data[i]); 88 } 89 } 90 91 out: 92 return IRQ_HANDLED; 93 } 94 95 static 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(&spi->dev, sizeof(*priv), GFP_KERNEL); 107 if (!priv) 108 return -ENOMEM; 109 110 priv->client = spi; 111 spi_set_drvdata(spi, 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(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); 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(&spi->dev, spi->irq, NULL, 133 ec_input_interrupt, 134 IRQF_ONESHOT, 135 "Ariel EC Input", 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 } 145 146 static const struct of_device_id ariel_pwrbutton_of_match[] = { 147 { .compatible = "dell,wyse-ariel-ec-input" }, 148 { } 149 }; 150 MODULE_DEVICE_TABLE(of, ariel_pwrbutton_of_match); 151 152 static struct spi_driver ariel_pwrbutton_driver = { 153 .driver = { 154 .name = "dell-wyse-ariel-ec-input", 155 .of_match_table = ariel_pwrbutton_of_match, 156 }, 157 .probe = ariel_pwrbutton_probe, 158 }; 159 module_spi_driver(ariel_pwrbutton_driver); 160 161 MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); 162 MODULE_DESCRIPTION("Dell Wyse 3020 Power Button Input Driver"); 163 MODULE_LICENSE("Dual BSD/GPL"); 164