[RFC PATCH 2/3] drivers/mfd: rpisense: Raspberry Pi senseHAT joystick driver

[Joel Savitz]

This patch implements support for the joystick, including a threaded
IRQ routine.

Signed-off-by: Charles Mirabile <cmirabil@xxxxxxxxxx>
Signed-off-by: Mwesigwa Guma <mguma@xxxxxxxxxx>
Signed-off-by: Joel Savitz <jsavitz@xxxxxxxxxx>
---
 drivers/mfd/Makefile      |   1 +
 drivers/mfd/rpisense-js.c | 132 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 drivers/mfd/rpisense-js.c

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 76f9a9221241..71356153ccdc 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -264,6 +264,7 @@ obj-$(CONFIG_MFD_ROHM_BD957XMUF)	+= rohm-bd9576.o
 obj-$(CONFIG_MFD_STMFX) 	+= stmfx.o
 obj-$(CONFIG_MFD_KHADAS_MCU) 	+= khadas-mcu.o
 obj-$(CONFIG_MFD_RPISENSE) 	+= rpisense-core.o
+obj-$(CONFIG_MFD_RPISENSE)	+= rpisense-js.o
 obj-$(CONFIG_MFD_ACER_A500_EC)	+= acer-ec-a500.o
 obj-$(CONFIG_MFD_QCOM_PM8008)	+= qcom-pm8008.o
 
diff --git a/drivers/mfd/rpisense-js.c b/drivers/mfd/rpisense-js.c
new file mode 100644
index 000000000000..c6c97bff118c
--- /dev/null
+++ b/drivers/mfd/rpisense-js.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Raspberry Pi Sense HAT joystick driver
+ * http://raspberrypi.org
+ *
+ * Copyright (C) 2015 Raspberry Pi
+ * Copyright (C) 2021 Charles Mirabile, Mwesigwa Guma, Joel Savitz
+ *
+ * Original Author: Serge Schneider
+ * Revised for upstream Linux by: Charles Mirabile, Mwesigwa Guma, Joel Savitz
+ */
+
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/gpio/consumer.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/rpisense.h>
+
+static unsigned char keymap[] = {KEY_DOWN, KEY_RIGHT, KEY_UP, KEY_ENTER, KEY_LEFT,};
+
+static irqreturn_t rpisense_js_report(int n, void *cookie)
+{
+	int i;
+	static s32 prev_keys;
+	struct rpisense *rpisense = cookie;
+	struct rpisense_js *rpisense_js = &rpisense->joystick;
+	s32 keys = rpisense_get_joystick_state(rpisense);
+	s32 changes = keys ^ prev_keys;
+
+	prev_keys = keys;
+	for (i = 0; i < ARRAY_SIZE(keymap); ++i) {
+		if (changes & (1<<i)) {
+			input_report_key(rpisense_js->keys_dev,
+					 keymap[i], keys & (1<<i));
+		}
+	}
+	input_sync(rpisense_js->keys_dev);
+	return IRQ_HANDLED;
+}
+
+static int rpisense_js_probe(struct platform_device *pdev)
+{
+	int ret;
+	int i;
+	struct rpisense *rpisense = dev_get_drvdata(&pdev->dev);
+	struct rpisense_js *rpisense_js = &rpisense->joystick;
+
+	rpisense_js->keys_desc = devm_gpiod_get(&rpisense->i2c_client->dev,
+						"keys-int", GPIOD_IN);
+	if (IS_ERR(rpisense_js->keys_desc)) {
+		dev_warn(&pdev->dev, "Failed to get keys-int descriptor.\n");
+		return PTR_ERR(rpisense_js->keys_desc);
+	}
+
+
+	rpisense_js->keys_dev = devm_input_allocate_device(&pdev->dev);
+	if (rpisense_js->keys_dev == NULL) {
+		dev_err(&pdev->dev, "Could not allocate input device.\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(keymap); i++) {
+		set_bit(keymap[i],
+			rpisense_js->keys_dev->keybit);
+	}
+
+	rpisense_js->keys_dev->name = "Raspberry Pi Sense HAT Joystick";
+	rpisense_js->keys_dev->phys = "rpi-sense-joy/input0";
+	rpisense_js->keys_dev->id.bustype = BUS_I2C;
+	rpisense_js->keys_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
+	rpisense_js->keys_dev->keycode = keymap;
+	rpisense_js->keys_dev->keycodesize = sizeof(unsigned char);
+	rpisense_js->keys_dev->keycodemax = ARRAY_SIZE(keymap);
+
+	ret = input_register_device(rpisense_js->keys_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not register input device.\n");
+		return ret;
+	}
+
+	ret = gpiod_direction_input(rpisense_js->keys_desc);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not set keys-int direction.\n");
+		return ret;
+	}
+
+	rpisense_js->keys_irq = gpiod_to_irq(rpisense_js->keys_desc);
+	if (rpisense_js->keys_irq < 0) {
+		dev_err(&pdev->dev, "Could not determine keys-int IRQ.\n");
+		return rpisense_js->keys_irq;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, rpisense_js->keys_irq,
+		NULL, rpisense_js_report, IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+		"keys", rpisense);
+
+	if (ret) {
+		dev_err(&pdev->dev, "IRQ request failed.\n");
+		return ret;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id rpisense_js_id[] = {
+	{ .compatible = "rpi,rpi-sense-js" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rpisense_js_id);
+#endif
+
+static struct platform_device_id rpisense_js_device_id[] = {
+	{ .name = "rpi-sense-js" },
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, rpisense_js_device_id);
+
+static struct platform_driver rpisense_js_driver = {
+	.probe = rpisense_js_probe,
+	.driver = {
+		.name = "rpi-sense-js",
+	},
+};
+
+module_platform_driver(rpisense_js_driver);
+
+MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
+MODULE_AUTHOR("Serge Schneider <serge@xxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.27.0