[PATCH 1/2] Input: cypress-sf - Add Cypress StreetFighter touchkey driver

[Yassine Oudjana <y.oudjana@protonmail.com>]

This adds support for Cypress StreetFighter touchkey controllers such as sf3155.
This driver supports enabling regulators and generating input events.
---
 drivers/input/keyboard/Kconfig      |  10 ++
 drivers/input/keyboard/Makefile     |   1 +
 drivers/input/keyboard/cypress-sf.c | 220 ++++++++++++++++++++++++++++
 3 files changed, 231 insertions(+)
 create mode 100644 drivers/input/keyboard/cypress-sf.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 32d15809ae58..9348cd604843 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -791,4 +791,14 @@ config KEYBOARD_MTK_PMIC
 	  To compile this driver as a module, choose M here: the
 	  module will be called pmic-keys.

+config KEYBOARD_CYPRESS_SF
+	tristate "Cypress StreetFighter touchkey support"
+	depends on I2C
+	help
+	  Say Y here if you want to enable support for Cypress StreetFighter
+	  touchkeys.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cypress-sf.
+
 endif
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 1d689fdd5c00..e3c8648f834e 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_KEYBOARD_BCM)		+= bcm-keypad.o
 obj-$(CONFIG_KEYBOARD_CAP11XX)		+= cap11xx.o
 obj-$(CONFIG_KEYBOARD_CLPS711X)		+= clps711x-keypad.o
 obj-$(CONFIG_KEYBOARD_CROS_EC)		+= cros_ec_keyb.o
+obj-$(CONFIG_KEYBOARD_CYPRESS_SF)	+= cypress-sf.o
 obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o
 obj-$(CONFIG_KEYBOARD_DLINK_DIR685)	+= dlink-dir685-touchkeys.o
 obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o
diff --git a/drivers/input/keyboard/cypress-sf.c b/drivers/input/keyboard/cypress-sf.c
new file mode 100644
index 000000000000..f0b52cede249
--- /dev/null
+++ b/drivers/input/keyboard/cypress-sf.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/regulator/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/pm.h>
+#include <linux/input.h>
+#include <linux/module.h>
+
+#define CYPRESS_SF_DEV_NAME "cypress-sf"
+
+#define CYPRESS_SF_REG_FW_VERSION	0x46
+#define CYPRESS_SF_REG_HW_VERSION	0x48
+#define CYPRESS_SF_REG_BUTTON_STATUS	0x4a
+
+struct cypress_sf_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct regulator_bulk_data regulators[2];
+	u32 *keycodes;
+	unsigned long keystates;
+	int num_keys;
+};
+
+static irqreturn_t cypress_sf_irq_handler(int irq, void *devid)
+{
+	struct cypress_sf_data *touchkey = devid;
+	unsigned long keystates;
+	bool curr_state, new_state;
+	int key;
+
+	keystates = i2c_smbus_read_byte_data(touchkey->client,
+					CYPRESS_SF_REG_BUTTON_STATUS);
+	if (keystates < 0) {
+		dev_err(&touchkey->client->dev, "Failed to read button status");
+		return IRQ_NONE;
+	}
+
+	for(key = 0; key < touchkey->num_keys; ++key) {
+		curr_state = test_bit(key, &touchkey->keystates);
+		new_state = test_bit(key, &keystates);
+
+		if(curr_state ^ new_state) {
+			dev_dbg(&touchkey->client->dev,\
+				"Key %d changed to %d", key, new_state);
+			input_report_key(touchkey->input_dev,
+					touchkey->keycodes[key],
+					new_state);
+		}
+	}
+	input_sync(touchkey->input_dev);
+	touchkey->keystates = keystates;
+
+	return IRQ_HANDLED;
+}
+
+static int cypress_sf_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	struct cypress_sf_data *touchkey;
+	u8 hw_version;
+	u16 fw_version;
+	int ret;
+	int i;
+
+	touchkey = devm_kzalloc(&client->dev, sizeof(*touchkey), GFP_KERNEL);
+	if(!touchkey)
+		return -ENOMEM;
+
+	touchkey->client = client;
+	i2c_set_clientdata(client, touchkey);
+
+	touchkey->regulators[0].supply = "vdd";
+	touchkey->regulators[1].supply = "avdd";
+
+	ret = devm_regulator_bulk_get(&client->dev,
+					ARRAY_SIZE(touchkey->regulators),
+					touchkey->regulators);
+	if(ret) {
+		dev_err(&client->dev, "Failed to get regulators: %d\n", ret);
+		return ret;
+	}
+
+	touchkey->num_keys = of_property_count_elems_of_size(client->dev.of_node,
+							"linux,keycodes",
+							sizeof(u32));
+	if(touchkey->num_keys < 0)
+		/* Default key count */
+		touchkey->num_keys = 2;
+
+	touchkey->keycodes = devm_kzalloc(&client->dev,
+				sizeof(u32) * touchkey->num_keys, GFP_KERNEL);
+	if(!touchkey->keycodes)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(client->dev.of_node, "linux,keycodes",
+						touchkey->keycodes, touchkey->num_keys);
+
+	if(touchkey->num_keys < 0) {
+		/* Default keycodes */
+		touchkey->keycodes[0] = KEY_BACK;
+		touchkey->keycodes[1] = KEY_MENU;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
+					touchkey->regulators);
+	if(ret) {
+		dev_err(&client->dev, "Failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	touchkey->input_dev = devm_input_allocate_device(&client->dev);
+	if(!touchkey->input_dev) {
+		dev_err(&client->dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	touchkey->input_dev->name = CYPRESS_SF_DEV_NAME;
+	touchkey->input_dev->id.bustype = BUS_I2C;
+
+	hw_version = i2c_smbus_read_byte_data(touchkey->client,
+				CYPRESS_SF_REG_HW_VERSION);
+	fw_version = i2c_smbus_read_word_data(touchkey->client,
+				CYPRESS_SF_REG_FW_VERSION);
+	if(hw_version < 0 || fw_version < 0)
+		dev_warn(&client->dev, "Failed to read versions\n");
+	else
+		dev_info(&client->dev, "HW version %d, FW version %d\n",
+				hw_version, fw_version);
+
+	for(i = 0; i < touchkey->num_keys; ++i)
+		input_set_capability(touchkey->input_dev, EV_KEY,
+					touchkey->keycodes[i]);
+
+	ret = input_register_device(touchkey->input_dev);
+	if(ret) {
+		dev_err(&client->dev,
+			"Failed to register input device: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&client->dev, client->irq,
+					NULL, cypress_sf_irq_handler,
+					IRQF_ONESHOT,
+					CYPRESS_SF_DEV_NAME, touchkey);
+	if(ret) {
+		dev_err(&client->dev,
+			"Failed to register threaded irq: %d", ret);
+		return ret;
+	}
+
+	return 0;
+};
+
+static int __maybe_unused cypress_sf_suspend(struct device *dev) {
+	struct i2c_client *client = to_i2c_client(dev);
+	struct cypress_sf_data *touchkey = i2c_get_clientdata(client);
+	int ret;
+
+	disable_irq(client->irq);
+	ret = regulator_bulk_disable(ARRAY_SIZE(touchkey->regulators),
+					touchkey->regulators);
+	if(ret) {
+		dev_err(dev, "Failed to disable regulators: %d", ret);
+		enable_irq(client->irq);
+		return ret;
+	}
+	dev_dbg(dev, "Suspended device");
+
+	return 0;
+}
+
+static int __maybe_unused cypress_sf_resume(struct device *dev) {
+	struct i2c_client *client = to_i2c_client(dev);
+	struct cypress_sf_data *touchkey = i2c_get_clientdata(client);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
+					touchkey->regulators);
+	if(ret) {
+		dev_err(dev, "Failed to enable regulators: %d", ret);
+		return ret;
+	}
+	enable_irq(client->irq);
+	dev_dbg(dev, "Resumed device");
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(cypress_sf_pm_ops,
+			 cypress_sf_suspend, cypress_sf_resume);
+
+static struct i2c_device_id cypress_sf_id_table[] = {
+	{ CYPRESS_SF_DEV_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, cypress_sf_id_table);
+
+static const struct of_device_id cypress_sf_of_match[] = {
+	{ .compatible = "cypress,sf3155", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, cypress_sf_of_match);
+
+static struct i2c_driver cypress_sf_driver = {
+	.driver = {
+		.name = CYPRESS_SF_DEV_NAME,
+		.pm = &cypress_sf_pm_ops,
+		.of_match_table = of_match_ptr(cypress_sf_of_match),
+	},
+	.id_table = cypress_sf_id_table,
+	.probe = cypress_sf_probe,
+};
+module_i2c_driver(cypress_sf_driver);
+
+MODULE_AUTHOR("Yassine Oudjana <y.oudjana@protonmail.com>");
+MODULE_DESCRIPTION("Cypress StreetFighter Touchkey Driver");
+MODULE_LICENSE("GPL v2");
--
2.31.1