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// 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 const struct spi_device_id ariel_pwrbutton_spi_ids[] = {
{ .name = "wyse-ariel-ec-input" },
{ }
};
MODULE_DEVICE_TABLE(spi, ariel_pwrbutton_spi_ids);
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,
.id_table = ariel_pwrbutton_spi_ids,
};
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");
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