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-rw-r--r--drivers/input/misc/ariel-pwrbutton.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/input/misc/ariel-pwrbutton.c b/drivers/input/misc/ariel-pwrbutton.c
new file mode 100644
index 0000000000..cdc80715b5
--- /dev/null
+++ b/drivers/input/misc/ariel-pwrbutton.c
@@ -0,0 +1,170 @@
+// 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");