1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
new file mode 100644
index 000000000..2d991325e
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Elan touchscreens that use the i2c-hid protocol.
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+
+#include "i2c-hid.h"
+
+struct elan_i2c_hid_chip_data {
+	unsigned int post_gpio_reset_delay_ms;
+	unsigned int post_power_delay_ms;
+	u16 hid_descriptor_address;
+};
+
+struct i2c_hid_of_elan {
+	struct i2chid_ops ops;
+
+	struct regulator *vcc33;
+	struct regulator *vccio;
+	struct gpio_desc *reset_gpio;
+	const struct elan_i2c_hid_chip_data *chip_data;
+};
+
+static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_elan *ihid_elan =
+		container_of(ops, struct i2c_hid_of_elan, ops);
+	int ret;
+
+	ret = regulator_enable(ihid_elan->vcc33);
+	if (ret)
+		return ret;
+
+	ret = regulator_enable(ihid_elan->vccio);
+	if (ret) {
+		regulator_disable(ihid_elan->vcc33);
+		return ret;
+	}
+
+	if (ihid_elan->chip_data->post_power_delay_ms)
+		msleep(ihid_elan->chip_data->post_power_delay_ms);
+
+	gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
+	if (ihid_elan->chip_data->post_gpio_reset_delay_ms)
+		msleep(ihid_elan->chip_data->post_gpio_reset_delay_ms);
+
+	return 0;
+}
+
+static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_elan *ihid_elan =
+		container_of(ops, struct i2c_hid_of_elan, ops);
+
+	gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
+	regulator_disable(ihid_elan->vccio);
+	regulator_disable(ihid_elan->vcc33);
+}
+
+static int i2c_hid_of_elan_probe(struct i2c_client *client,
+				 const struct i2c_device_id *id)
+{
+	struct i2c_hid_of_elan *ihid_elan;
+
+	ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
+	if (!ihid_elan)
+		return -ENOMEM;
+
+	ihid_elan->ops.power_up = elan_i2c_hid_power_up;
+	ihid_elan->ops.power_down = elan_i2c_hid_power_down;
+
+	/* Start out with reset asserted */
+	ihid_elan->reset_gpio =
+		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ihid_elan->reset_gpio))
+		return PTR_ERR(ihid_elan->reset_gpio);
+
+	ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
+	if (IS_ERR(ihid_elan->vccio))
+		return PTR_ERR(ihid_elan->vccio);
+
+	ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33");
+	if (IS_ERR(ihid_elan->vcc33))
+		return PTR_ERR(ihid_elan->vcc33);
+
+	ihid_elan->chip_data = device_get_match_data(&client->dev);
+
+	return i2c_hid_core_probe(client, &ihid_elan->ops,
+				  ihid_elan->chip_data->hid_descriptor_address, 0);
+}
+
+static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
+	.post_power_delay_ms = 1,
+	.post_gpio_reset_delay_ms = 300,
+	.hid_descriptor_address = 0x0001,
+};
+
+static const struct of_device_id elan_i2c_hid_of_match[] = {
+	{ .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
+
+static struct i2c_driver elan_i2c_hid_ts_driver = {
+	.driver = {
+		.name	= "i2c_hid_of_elan",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table = of_match_ptr(elan_i2c_hid_of_match),
+	},
+	.probe		= i2c_hid_of_elan_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+};
+module_i2c_driver(elan_i2c_hid_ts_driver);
+
+MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
+MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
+MODULE_LICENSE("GPL");