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