[PATCH] Input: add switch event(SW_EXT_PEN_ATTACHED)

From: HyungJae Im
Date: Fri Oct 30 2020 - 02:27:53 EST


We need support to various accessories on the device,
some requiring switch does not exist in switch list.
So added switch for the following purpose.

SW_EXT_PEN_ATTACHED is for the checking the external pen
attached or not on the device. We also added driver
that uses such event.

Signed-off-by: Hyungjae Im <hj2.im@xxxxxxxxxxx>
---
drivers/input/Kconfig | 12 ++
drivers/input/Makefile | 1 +
drivers/input/ext_pen_detect.c | 237 +++++++++++++++++++++++++
include/linux/mod_devicetable.h | 2 +-
include/uapi/linux/input-event-codes.h | 3 +-
5 files changed, 253 insertions(+), 2 deletions(-)
create mode 100644 drivers/input/ext_pen_detect.c

diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index ba5e7444c547..5d6d15c8f7e7 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -197,6 +197,18 @@ config INPUT_COVER_DETECT
To compile this driver as a module, choose M here: the
module will be called cover_detect.

+config INPUT_EXT_PEN_DETECT
+ tristate "Enable external pen attach detection"
+ help
+ Say Y here to enable external pen detection
+ and send a event when external pen is attached/detached.
+ Active gpio state is low and active event value is 0.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ext_pen_detect.
+
comment "Input Device Drivers"

source "drivers/input/keyboard/Kconfig"
diff --git a/drivers/input/Makefile b/drivers/input/Makefile
index fc8dd9091821..0ccf02e34557 100644
--- a/drivers/input/Makefile
+++ b/drivers/input/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_INPUT_APMPOWER) += apm-power.o
obj-$(CONFIG_RMI4_CORE) += rmi4/

obj-$(CONFIG_INPUT_COVER_DETECT)+= cover_detect.o
+obj-$(CONFIG_INPUT_EXT_PEN_DETECT)+= ext_pen_detect.o
diff --git a/drivers/input/ext_pen_detect.c b/drivers/input/ext_pen_detect.c
new file mode 100644
index 000000000000..9a0d106e49f8
--- /dev/null
+++ b/drivers/input/ext_pen_detect.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Support detection pen attachment externally on device
+ *
+ * Copyright (C) 2020 Samsung Electronics Co. Ltd. All Rights Reserved.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/wakelock.h>
+
+struct ext_pen_detect_drvdata {
+ struct input_dev *input;
+ struct delayed_work ext_pen_detect_dwork;
+ struct wakeup_source *ws;
+ int gpio_ext_pen_detect;
+ int irq_ext_pen_detect;
+};
+
+static void ext_pen_detect_work(struct work_struct *work)
+{
+ struct ext_pen_detect_drvdata *ddata =
+ container_of(work, struct ext_pen_detect_drvdata,
+ ext_pen_detect_dwork.work);
+ bool ext_pen_status;
+
+ ext_pen_status = gpio_get_value(ddata->gpio_ext_pen_detect);
+
+ input_report_switch(ddata->input,
+ SW_EXT_PEN_ATTACHED, ext_pen_status);
+ input_sync(ddata->input);
+}
+
+static void __ext_pen_detect(struct ext_pen_detect_drvdata *ddata,
+ bool ext_pen_status)
+{
+ cancel_delayed_work_sync(&ddata->ext_pen_detect_dwork);
+ if (ext_pen_status) {
+ __pm_wakeup_event(ddata->ws, jiffies_to_msecs(HZ / 20));
+ schedule_delayed_work(&ddata->ext_pen_detect_dwork,
+ HZ * 1 / 100);
+ } else {
+ __pm_relax(ddata->ws);
+ schedule_delayed_work(&ddata->ext_pen_detect_dwork, 0);
+ }
+}
+
+static irqreturn_t ext_pen_detect_irq(int irq, void *dev_id)
+{
+ bool ext_pen_status;
+ struct ext_pen_detect_drvdata *ddata = dev_id;
+
+ ext_pen_status = gpio_get_value(ddata->gpio_ext_pen_detect);
+
+ __ext_pen_detect(ddata, ext_pen_status);
+
+ return IRQ_HANDLED;
+}
+
+static int ext_pen_detect_open(struct input_dev *input)
+{
+ struct ext_pen_detect_drvdata *ddata = input_get_drvdata(input);
+ /* update the current status */
+ schedule_delayed_work(&ddata->ext_pen_detect_dwork, HZ / 2);
+ /* Report current state of buttons that are connected to GPIOs */
+ input_sync(input);
+
+ return 0;
+}
+
+static void ext_pen_detect_close(struct input_dev *input)
+{
+}
+
+static void init_ext_pen_detect_irq(struct input_dev *input)
+{
+ struct ext_pen_detect_drvdata *ddata = input_get_drvdata(input);
+
+ int ret = 0;
+ int irq = ddata->irq_ext_pen_detect;
+
+ ret = request_threaded_irq(
+ irq, NULL,
+ ext_pen_detect_irq,
+ IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ "ext_pen_detect", ddata);
+ if (ret < 0)
+ pr_err("keys: failed to request ext_pen detect irq %d gpio %d\n",
+ irq, ddata->gpio_ext_pen_detect);
+}
+
+#ifdef CONFIG_OF
+static int of_ext_pen_detect_data_parsing_dt(struct device *dev,
+ struct ext_pen_detect_drvdata *ddata)
+{
+ struct device_node *np = dev->of_node;
+ int gpio;
+ enum of_gpio_flags flags;
+
+ gpio = of_get_named_gpio_flags(np, "gpio_ext_pen_detect", 0, &flags);
+ ddata->gpio_ext_pen_detect = gpio;
+
+ ddata->irq_ext_pen_detect = gpio_to_irq(gpio);
+
+ return 0;
+}
+#endif
+
+static int ext_pen_detect_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ext_pen_detect_drvdata *ddata;
+ struct input_dev *input;
+ int error;
+ int wakeup = 0;
+
+ ddata = kzalloc(sizeof(struct ext_pen_detect_drvdata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+#ifdef CONFIG_OF
+ if (dev->of_node) {
+ error = of_ext_pen_detect_data_parsing_dt(dev, ddata);
+ if (error < 0) {
+ dev_err(dev, "fail to get the devicetree, error: %d\n",
+ error);
+ goto fail1;
+ }
+ }
+#endif
+
+ input = input_allocate_device();
+ if (!input) {
+ dev_err(dev, "failed to allocate state\n");
+ error = -ENOMEM;
+ goto fail1;
+ }
+
+ ddata->input = input;
+
+ ddata->ws = wakeup_source_register(NULL, "ext_pen_detect");
+
+ platform_set_drvdata(pdev, ddata);
+ input_set_drvdata(input, ddata);
+
+ input->name = "ext_pen_detect";
+ input->phys = "ext_pen_detect";
+ input->dev.parent = &pdev->dev;
+
+ input->evbit[0] |= BIT_MASK(EV_SW);
+ input_set_capability(input, EV_SW, SW_EXT_PEN_ATTACHED);
+
+ input->open = ext_pen_detect_open;
+ input->close = ext_pen_detect_close;
+
+ /* Enable auto repeat feature of Linux input subsystem */
+ __set_bit(EV_REP, input->evbit);
+
+ INIT_DELAYED_WORK(&ddata->ext_pen_detect_dwork, ext_pen_detect_work);
+
+ init_ext_pen_detect_irq(input);
+
+ if (ddata->gpio_ext_pen_detect != 0) {
+ error = input_register_device(input);
+ if (error) {
+ dev_err(dev, "Unable to register input device, error: %d\n",
+ error);
+ goto fail1;
+ }
+ }
+
+ device_init_wakeup(&pdev->dev, wakeup);
+
+ return 0;
+
+ fail1:
+ kfree(ddata);
+
+ return error;
+}
+
+static int ext_pen_detect_remove(struct platform_device *pdev)
+{
+ struct ext_pen_detect_drvdata *ddata = platform_get_drvdata(pdev);
+ struct input_dev *input = ddata->input;
+
+ device_init_wakeup(&pdev->dev, 0);
+
+ input_unregister_device(input);
+
+ wakeup_source_unregister(ddata->ws);
+
+ kfree(ddata);
+
+ return 0;
+}
+
+#if defined(CONFIG_OF)
+static const struct of_device_id ext_pen_detect_dt_ids[] = {
+ { .compatible = "ext_pen_detect" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ext_pen_detect_dt_ids);
+#endif /* CONFIG_OF */
+
+static struct platform_driver ext_pen_detect_device_driver = {
+ .probe = ext_pen_detect_probe,
+ .remove = ext_pen_detect_remove,
+ .driver = {
+ .name = "ext_pen_detect",
+ .owner = THIS_MODULE,
+#if defined(CONFIG_OF)
+ .of_match_table = ext_pen_detect_dt_ids,
+#endif /* CONFIG_OF */
+ }
+};
+
+static int __init ext_pen_detect_init(void)
+{
+ return platform_driver_register(&ext_pen_detect_device_driver);
+}
+
+static void __exit ext_pen_detect_exit(void)
+{
+ platform_driver_unregister(&ext_pen_detect_device_driver);
+}
+
+module_init(ext_pen_detect_init);
+module_exit(ext_pen_detect_exit);
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 2e6ae686555b..897f5a3e7721 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -320,7 +320,7 @@ struct pcmcia_device_id {
#define INPUT_DEVICE_ID_LED_MAX 0x0f
#define INPUT_DEVICE_ID_SND_MAX 0x07
#define INPUT_DEVICE_ID_FF_MAX 0x7f
-#define INPUT_DEVICE_ID_SW_MAX 0x11
+#define INPUT_DEVICE_ID_SW_MAX 0x12
#define INPUT_DEVICE_ID_PROP_MAX 0x1f

#define INPUT_DEVICE_ID_MATCH_BUS 1
diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
index 32e27732161c..8ca2acee1f92 100644
--- a/include/uapi/linux/input-event-codes.h
+++ b/include/uapi/linux/input-event-codes.h
@@ -890,7 +890,8 @@
#define SW_PEN_INSERTED 0x0f /* set = pen inserted */
#define SW_MACHINE_COVER 0x10 /* set = cover closed */
#define SW_COVER_ATTACHED 0x11 /* set = cover attached */
-#define SW_MAX 0x11
+#define SW_EXT_PEN_ATTACHED 0x12 /* set = external pen attached */
+#define SW_MAX 0x12
#define SW_CNT (SW_MAX+1)

/*
--
2.17.1