[RFC 4/4] input: misc: Add Gateworks System Controller support

[Tim Harvey]

Add support for dispatching Linux Input events for the various interrupts
the Gateworks System Controller provides.

Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
---
 drivers/input/misc/Kconfig     |   6 ++
 drivers/input/misc/Makefile    |   1 +
 drivers/input/misc/gsc-input.c | 196 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 203 insertions(+)
 create mode 100644 drivers/input/misc/gsc-input.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 9f082a3..3d18a0e 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -117,6 +117,12 @@ config INPUT_E3X0_BUTTON
 	  To compile this driver as a module, choose M here: the
 	  module will be called e3x0_button.
 
+config INPUT_GSC
+	tristate "Gateworks System Controller input support"
+	depends on MFD_GSC
+	help
+	  Say Y here if you want Gateworks System Controller input support.
+
 config INPUT_PCSPKR
 	tristate "PC Speaker support"
 	depends on PCSPKR_PLATFORM
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 4b6118d..969debe 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_INPUT_GP2A)		+= gp2ap002a00f.o
 obj-$(CONFIG_INPUT_GPIO_BEEPER)		+= gpio-beeper.o
 obj-$(CONFIG_INPUT_GPIO_TILT_POLLED)	+= gpio_tilt_polled.o
 obj-$(CONFIG_INPUT_GPIO_DECODER)	+= gpio_decoder.o
+obj-$(CONFIG_INPUT_GSC)			+= gsc-input.o
 obj-$(CONFIG_INPUT_HISI_POWERKEY)	+= hisi_powerkey.o
 obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
 obj-$(CONFIG_INPUT_IMS_PCU)		+= ims-pcu.o
diff --git a/drivers/input/misc/gsc-input.c b/drivers/input/misc/gsc-input.c
new file mode 100644
index 0000000..7cf217c
--- /dev/null
+++ b/drivers/input/misc/gsc-input.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Gateworks Corporation
+ */
+#define DEBUG
+
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/gsc.h>
+
+struct gsc_irq {
+	unsigned int irq;
+	const char *name;
+	unsigned int virq;
+};
+
+static struct gsc_irq gsc_irqs[] = {
+	{ GSC_IRQ_PB,		"button" },
+	{ GSC_IRQ_KEY_ERASED,	"key-erased" },
+	{ GSC_IRQ_EEPROM_WP,	"eeprom-wp" },
+	{ GSC_IRQ_TAMPER,	"tamper" },
+	{ GSC_IRQ_SWITCH_HOLD,	"button-held" },
+};
+
+struct gsc_input_info {
+	struct device *dev;
+	struct gsc_dev *gsc;
+	struct input_dev *input;
+
+	int irq;
+	struct work_struct irq_work;
+	struct mutex mutex;
+};
+
+static void gsc_input_irq_work(struct work_struct *work)
+{
+	struct gsc_input_info *info = container_of(work, struct gsc_input_info,
+						   irq_work);
+	struct gsc_dev *gsc = info->gsc;
+	int i, ret = 0;
+	int key, sts;
+	struct gsc_irq *gsc_irq = NULL;
+
+	dev_dbg(gsc->dev, "%s irq%d\n", __func__, info->irq);
+	mutex_lock(&info->mutex);
+
+	for (i = 0; i < ARRAY_SIZE(gsc_irqs);i++)
+		if (info->irq == gsc_irqs[i].virq)
+			gsc_irq = &gsc_irqs[i];
+	if (!gsc_irq) {
+		dev_err(info->dev, "interrupt: irq%d occurred\n", info->irq);
+		mutex_unlock(&info->mutex);
+		return;
+	}
+
+	ret = regmap_read(info->gsc->regmap, GSC_IRQ_STATUS, &sts);
+	if (ret) {
+		dev_err(info->dev, "failed to read status register\n");
+		mutex_unlock(&info->mutex);
+		return;
+	}
+
+	key = -1;
+	switch (gsc_irq->virq) {
+	case GSC_IRQ_PB:
+		key = BTN_0;
+		break;
+	case GSC_IRQ_KEY_ERASED:
+		key = BTN_1;
+		break;
+	case GSC_IRQ_EEPROM_WP:
+		key = BTN_2;
+		break;
+	case GSC_IRQ_GPIO:
+		key = BTN_3;
+		break;
+	case GSC_IRQ_TAMPER:
+		key = BTN_4;
+		break;
+	case GSC_IRQ_SWITCH_HOLD:
+		key = BTN_5;
+		break;
+	}
+
+	if (key != -1) {
+		dev_dbg(&info->input->dev, "bit%d: key=0x%03x %s\n",
+			gsc_irq->virq, key, gsc_irq->name);
+		input_report_key(info->input, key, 1);
+		input_report_key(info->input, key, 0);
+		input_sync(info->input);
+	}
+
+	mutex_unlock(&info->mutex);
+}
+
+static irqreturn_t gsc_input_irq(int irq, void *data)
+{
+	struct gsc_input_info *info = data;
+
+	dev_dbg(info->gsc->dev, "%s irq%d\n", __func__, irq);
+	info->irq = irq;
+	schedule_work(&info->irq_work);
+
+	return IRQ_HANDLED;
+}
+
+static int gsc_input_probe(struct platform_device *pdev)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(pdev->dev.parent);
+	struct gsc_input_info *info;
+	struct input_dev *input;
+	int ret, i;
+
+	dev_dbg(&pdev->dev, "%s\n", __func__);
+	info = devm_kzalloc(&pdev->dev, sizeof(struct gsc_input_info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->dev = &pdev->dev;
+	info->gsc = gsc;
+
+	/* Register input device */
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input) {
+		dev_err(&pdev->dev, "Can't allocate input device\n");
+		return -ENOMEM;
+	}
+	info->input = input;
+
+	input->name = KBUILD_MODNAME;
+	input->dev.parent = &pdev->dev;
+
+	input_set_capability(input, EV_KEY, BTN_0); /* button */
+	input_set_capability(input, EV_KEY, BTN_1); /* key erased */
+	input_set_capability(input, EV_KEY, BTN_2); /* ee wp */
+	input_set_capability(input, EV_KEY, BTN_3); /* gpio */
+	input_set_capability(input, EV_KEY, BTN_4); /* tamper */
+	input_set_capability(input, EV_KEY, BTN_5); /* button held */
+
+	ret = input_register_device(input);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Can't register input device: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, gsc);
+	mutex_init(&info->mutex);
+	INIT_WORK(&info->irq_work, gsc_input_irq_work);
+
+	/* Support irq domain */
+	for (i = 0; i < ARRAY_SIZE(gsc_irqs); i++) {
+		struct gsc_irq *gsc_irq = &gsc_irqs[i];
+		int virq;
+
+		virq = regmap_irq_get_virq(gsc->irq_chip_data, gsc_irq->irq);
+		if (virq <= 0)
+			return -EINVAL;
+		gsc_irq->virq = virq;
+
+		ret = devm_request_threaded_irq(&pdev->dev, virq, NULL,
+						gsc_input_irq, 0,
+						gsc_irq->name, info);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"failed: irq request (IRQ: %d, error: %d\n)",
+				gsc_irq->irq, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id gsc_input_dt_ids[] = {
+	{ .compatible = "gw,gsc-input", },
+	{}
+};
+
+static struct platform_driver gsc_input_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = gsc_input_dt_ids,
+	},
+	.probe = gsc_input_probe,
+};
+
+module_platform_driver(gsc_input_driver);
+
+MODULE_AUTHOR("Tim Harvey <tharvey@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("GSC input driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4