Merge branch 'for-5.20/elan' into for-linus

- support for Elan eKTH6915 touchscreens (Douglas Anderson)

3 files changed, 146 insertions, 0 deletions

diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
index a16c6a69680b..5273ee2bb134 100644
--- a/drivers/hid/i2c-hid/Kconfig
+++ b/drivers/hid/i2c-hid/Kconfig
@@ -32,6 +32,21 @@ config I2C_HID_OF
 	  will be called i2c-hid-of.  It will also build/depend on the
 	  module i2c-hid.
 
+config I2C_HID_OF_ELAN
+	tristate "Driver for Elan hid-i2c based devices on OF systems"
+	default n
+	depends on I2C && INPUT && OF
+	help
+	  Say Y here if you want support for Elan i2c devices that use
+	  the i2c-hid protocol on Open Firmware (Device Tree)-based
+	  systems.
+
+	  If unsure, say N.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-hid-of-elan.  It will also build/depend on
+	  the module i2c-hid.
+
 config I2C_HID_OF_GOODIX
 	tristate "Driver for Goodix hid-i2c based devices on OF systems"
 	default n
diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile
index 302545a771f3..55bd5e0f35af 100644
--- a/drivers/hid/i2c-hid/Makefile
+++ b/drivers/hid/i2c-hid/Makefile
@@ -10,4 +10,5 @@ i2c-hid-$(CONFIG_DMI)				+= i2c-hid-dmi-quirks.o
 
 obj-$(CONFIG_I2C_HID_ACPI)			+= i2c-hid-acpi.o
 obj-$(CONFIG_I2C_HID_OF)			+= i2c-hid-of.o
+obj-$(CONFIG_I2C_HID_OF_ELAN)			+= i2c-hid-of-elan.o
 obj-$(CONFIG_I2C_HID_OF_GOODIX)			+= i2c-hid-of-goodix.o
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 000000000000..2d991325e734
--- /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");