| // SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later |
| /* |
| * Dell Wyse 3020 a.k.a. "Ariel" Power Button Driver |
| * |
| * Copyright (C) 2020 Lubomir Rintel |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/gfp.h> |
| #include <linux/input.h> |
| #include <linux/interrupt.h> |
| #include <linux/mod_devicetable.h> |
| #include <linux/module.h> |
| #include <linux/spi/spi.h> |
| |
| #define RESP_COUNTER(response) (response.header & 0x3) |
| #define RESP_SIZE(response) ((response.header >> 2) & 0x3) |
| #define RESP_TYPE(response) ((response.header >> 4) & 0xf) |
| |
| struct ec_input_response { |
| u8 reserved; |
| u8 header; |
| u8 data[3]; |
| } __packed; |
| |
| struct ariel_pwrbutton { |
| struct spi_device *client; |
| struct input_dev *input; |
| u8 msg_counter; |
| }; |
| |
| static int ec_input_read(struct ariel_pwrbutton *priv, |
| struct ec_input_response *response) |
| { |
| u8 read_request[] = { 0x00, 0x5a, 0xa5, 0x00, 0x00 }; |
| struct spi_device *spi = priv->client; |
| struct spi_transfer t = { |
| .tx_buf = read_request, |
| .rx_buf = response, |
| .len = sizeof(read_request), |
| }; |
| |
| compiletime_assert(sizeof(read_request) == sizeof(*response), |
| "SPI xfer request/response size mismatch"); |
| |
| return spi_sync_transfer(spi, &t, 1); |
| } |
| |
| static irqreturn_t ec_input_interrupt(int irq, void *dev_id) |
| { |
| struct ariel_pwrbutton *priv = dev_id; |
| struct spi_device *spi = priv->client; |
| struct ec_input_response response; |
| int error; |
| int i; |
| |
| error = ec_input_read(priv, &response); |
| if (error < 0) { |
| dev_err(&spi->dev, "EC read failed: %d\n", error); |
| goto out; |
| } |
| |
| if (priv->msg_counter == RESP_COUNTER(response)) { |
| dev_warn(&spi->dev, "No new data to read?\n"); |
| goto out; |
| } |
| |
| priv->msg_counter = RESP_COUNTER(response); |
| |
| if (RESP_TYPE(response) != 0x3 && RESP_TYPE(response) != 0xc) { |
| dev_dbg(&spi->dev, "Ignoring message that's not kbd data\n"); |
| goto out; |
| } |
| |
| for (i = 0; i < RESP_SIZE(response); i++) { |
| switch (response.data[i]) { |
| case 0x74: |
| input_report_key(priv->input, KEY_POWER, 1); |
| input_sync(priv->input); |
| break; |
| case 0xf4: |
| input_report_key(priv->input, KEY_POWER, 0); |
| input_sync(priv->input); |
| break; |
| default: |
| dev_dbg(&spi->dev, "Unknown scan code: %02x\n", |
| response.data[i]); |
| } |
| } |
| |
| out: |
| return IRQ_HANDLED; |
| } |
| |
| static int ariel_pwrbutton_probe(struct spi_device *spi) |
| { |
| struct ec_input_response response; |
| struct ariel_pwrbutton *priv; |
| int error; |
| |
| if (!spi->irq) { |
| dev_err(&spi->dev, "Missing IRQ.\n"); |
| return -EINVAL; |
| } |
| |
| priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); |
| if (!priv) |
| return -ENOMEM; |
| |
| priv->client = spi; |
| spi_set_drvdata(spi, priv); |
| |
| priv->input = devm_input_allocate_device(&spi->dev); |
| if (!priv->input) |
| return -ENOMEM; |
| priv->input->name = "Power Button"; |
| priv->input->dev.parent = &spi->dev; |
| input_set_capability(priv->input, EV_KEY, KEY_POWER); |
| error = input_register_device(priv->input); |
| if (error) { |
| dev_err(&spi->dev, "error registering input device: %d\n", error); |
| return error; |
| } |
| |
| error = ec_input_read(priv, &response); |
| if (error < 0) { |
| dev_err(&spi->dev, "EC read failed: %d\n", error); |
| return error; |
| } |
| priv->msg_counter = RESP_COUNTER(response); |
| |
| error = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, |
| ec_input_interrupt, |
| IRQF_ONESHOT, |
| "Ariel EC Input", priv); |
| |
| if (error) { |
| dev_err(&spi->dev, "Failed to request IRQ %d: %d\n", |
| spi->irq, error); |
| return error; |
| } |
| |
| return 0; |
| } |
| |
| static const struct of_device_id ariel_pwrbutton_of_match[] = { |
| { .compatible = "dell,wyse-ariel-ec-input" }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(of, ariel_pwrbutton_of_match); |
| |
| static struct spi_driver ariel_pwrbutton_driver = { |
| .driver = { |
| .name = "dell-wyse-ariel-ec-input", |
| .of_match_table = ariel_pwrbutton_of_match, |
| }, |
| .probe = ariel_pwrbutton_probe, |
| }; |
| module_spi_driver(ariel_pwrbutton_driver); |
| |
| MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); |
| MODULE_DESCRIPTION("Dell Wyse 3020 Power Button Input Driver"); |
| MODULE_LICENSE("Dual BSD/GPL"); |