This patch adds a generic driver for slide switches connected to GPIO
pins of a system. It requires gpiolib and generic hardware irqs.
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxxxxxx>
---
drivers/input/misc/Kconfig | 9 ++
drivers/input/misc/Makefile | 1 +
drivers/input/misc/slide_switch.c | 268 ++++++++++++++++++++++++++++++++++++
include/linux/input/slide_switch.h | 16 ++
4 files changed, 294 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/misc/slide_switch.c
create mode 100644 include/linux/input/slide_switch.h
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index b0c6772..ba9395c 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -341,6 +341,15 @@ config INPUT_GPIO_ROTARY_ENCODER
To compile this driver as a module, choose M here: the
module will be called rotary_encoder.
+config INPUT_GPIO_SLIDE_SWITCH
+ tristate "Slide switches connected to GPIO pins"
+ depends on GPIOLIB && GENERIC_GPIO
+ help
+ Say Y here to add support for slide switches connected to GPIO lines.
+
+ To compile this driver as a module, choose M here: the
+ module will be called slide_switch.
+
config INPUT_RB532_BUTTON
tristate "Mikrotik Routerboard 532 button interface"
depends on MIKROTIK_RB532
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 9b47971..d81fdc9 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_POWERMATE) += powermate.o
obj-$(CONFIG_INPUT_PWM_BEEPER) += pwm-beeper.o
obj-$(CONFIG_INPUT_RB532_BUTTON) += rb532_button.o
obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER) += rotary_encoder.o
+obj-$(CONFIG_INPUT_GPIO_SLIDE_SWITCH) += slide_switch.o
obj-$(CONFIG_INPUT_SGI_BTNS) += sgi_btns.o
obj-$(CONFIG_INPUT_SPARCSPKR) += sparcspkr.o
obj-$(CONFIG_INPUT_TWL4030_PWRBUTTON) += twl4030-pwrbutton.o
diff --git a/drivers/input/misc/slide_switch.c b/drivers/input/misc/slide_switch.c
new file mode 100644
index 0000000..0f69b3a
--- /dev/null
+++ b/drivers/input/misc/slide_switch.c
@@ -0,0 +1,268 @@
+/*
+ * slide_switch.c
+ *
+ * (c) 2011 Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxxxxxx>
+ *
+ * A generic driver for slide switches connected to GPIO lines.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define DEBUG
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/input/slide_switch.h>
+
+#define DRV_NAME "slide-switch"
+
+struct slide_switch {
+ struct input_dev *input;
+ struct slide_switch_platform_data *pdata;
+
+ struct timer_list timer;
+ struct work_struct work;
+ int timer_debounce; /* in msecs */
+};
+
+static void slide_switch_report_event(struct slide_switch *slide_switch)
+{
+ struct input_dev *input = slide_switch->input;
+ struct slide_switch_platform_data *pdata = slide_switch->pdata;
+ unsigned long posbit;
+ int i, on, pos, invalidpos;
+
+ posbit = 0;
+ for (i = 0; i < pdata->gpios; i++) {
+ on = gpio_get_value(pdata->gpiolist[i].gpio) ? 1 : 0;
+ on ^= pdata->gpiolist[i].inverted;
+ if (on)
+ set_bit(i, &posbit);
+ }
+
+ pos = find_first_bit(&posbit, pdata->gpios);
+ invalidpos = find_next_bit(&posbit, pdata->gpios, pos + 1);
+
+ /* Check if there is only one bit set */
+ if (pos < pdata->gpios && invalidpos == pdata->gpios) {
+ input_report_abs(slide_switch->input, pdata->axis, pos);
+ input_sync(input);
+ }
+}
+
+static void slide_switch_work_func(struct work_struct *work)
+{
+ struct slide_switch *slide_switch =
+ container_of(work, struct slide_switch, work);
+
+ slide_switch_report_event(slide_switch);
+}
+
+static void slide_switch_timer(unsigned long _data)
+{
+ struct slide_switch *slide_switch = (struct slide_switch *)_data;
+
+ schedule_work(&slide_switch->work);
+}
+
+static irqreturn_t slide_switch_irq(int irq, void *dev_id)
+{
+ struct slide_switch *slide_switch = dev_id;
+
+ if (slide_switch->timer_debounce)
+ mod_timer(&slide_switch->timer,
+ jiffies + msecs_to_jiffies(slide_switch->timer_debounce));
+ else
+ schedule_work(&slide_switch->work);
+
+ return IRQ_HANDLED;
+}
+
+static int slide_switch_register_gpios(struct device *dev,
+ const struct slide_switch_gpio *gpio,
+ struct slide_switch *slide_switch)
+{
+ int err, gpio_num, irq;
+ struct slide_switch_platform_data *pdata = slide_switch->pdata;
+
+ gpio_num = gpio->gpio;
+ irq = gpio_to_irq(gpio_num);
+
+ err = gpio_request(gpio_num, DRV_NAME);
+ if (err) {
+ dev_err(dev, "unable to request GPIO %d\n",
+ gpio_num);
+ goto exit_fail;
+ }
+
+ err = gpio_direction_input(gpio_num);
+ if (err) {
+ dev_err(dev, "unable to set GPIO %d for input\n",
+ gpio_num);
+ goto exit_unregister_gpio;
+ }
+
+ if (pdata->debounce_ms) {
+ err = gpio_set_debounce(gpio_num,
+ pdata->debounce_ms * 1000);
+ /* use timer if gpiolib doesn't provide debounce */
+ if (err < 0)
+ slide_switch->timer_debounce = pdata->debounce_ms;
+ }
+
+ /* request the IRQs */
+ err = request_irq(irq, &slide_switch_irq,
+ IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+ DRV_NAME, slide_switch);
+ if (err) {
+ dev_err(dev, "unable to request IRQ %d\n",
+ irq);
+ goto exit_unregister_gpio;
+ }
+
+ return 0;
+
+exit_unregister_gpio:
+ gpio_free(gpio_num);
+exit_fail:
+
+ return 1;
+}
+
+static void slide_switch_unregister_gpios(struct device *dev,
+ const struct slide_switch_gpio *gpio,
+ struct slide_switch *slide_switch)
+{
+ int gpio_num, irq;
+
+ gpio_num = gpio->gpio;
+ irq = gpio_to_irq(gpio_num);
+
+ free_irq(irq, slide_switch);
+ gpio_free(gpio_num);
+}
+
+static int __devinit slide_switch_probe(struct platform_device *pdev)
+{
+ struct slide_switch_platform_data *pdata = pdev->dev.platform_data;
+ struct slide_switch *slide_switch;
+ struct input_dev *input;
+ int err, i;
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "missing platform data\n");
+ return -ENOENT;
+ }
+
+ if (!pdata->gpios || !pdata->gpiolist) {
+ dev_err(&pdev->dev, "no GPIOs provided\n");
+ return -ENOENT;
+ }
+
+ slide_switch = kzalloc(sizeof(struct slide_switch), GFP_KERNEL);
+ input = input_allocate_device();
+ if (!slide_switch || !input) {
+ dev_err(&pdev->dev, "failed to allocate memory for device\n");
+ err = -ENOMEM;
+ goto exit_free_mem;
+ }
+
+ slide_switch->input = input;
+ slide_switch->pdata = pdata;
+
+ /* create and register the input driver */
+ input->name = pdev->name;
+ input->id.bustype = BUS_HOST;
+ input->dev.parent = &pdev->dev;
+
+ input->evbit[0] = BIT_MASK(EV_ABS);
+ input_set_abs_params(slide_switch->input,
+ pdata->axis, 0, pdata->gpios, 0, 0);
+
+ err = input_register_device(input);
+ if (err) {
+ dev_err(&pdev->dev, "failed to register input device\n");
+ goto exit_free_mem;
+ }
+
+ setup_timer(&slide_switch->timer, slide_switch_timer,
+ (unsigned long)slide_switch);
+ INIT_WORK(&slide_switch->work, slide_switch_work_func);
+
+ /* Register GPIOs */
+ for (i = 0; i < pdata->gpios; i++) {
+ err = slide_switch_register_gpios(&pdev->dev,
+ &pdata->gpiolist[i], slide_switch);
+ if (err) {
+ for (i--; i >= 0; i--) {
+ slide_switch_unregister_gpios(&pdev->dev,
+ &pdata->gpiolist[i], slide_switch);
+ }
+ goto exit_unregister_input;
+ }
+ }
+
+ platform_set_drvdata(pdev, slide_switch);
+
+ return 0;
+
+exit_unregister_input:
+ input_unregister_device(input);
+ input = NULL; /* so we don't try to free it */
+exit_free_mem:
+ input_free_device(input);
+ kfree(slide_switch);
+ return err;
+}
+
+static int __devexit slide_switch_remove(struct platform_device *pdev)
+{
+ struct slide_switch *slide_switch = platform_get_drvdata(pdev);
+ struct slide_switch_platform_data *pdata = pdev->dev.platform_data;
+ int i;
+
+ /* Unregister GPIOs */
+ for (i = 0; i < pdata->gpios; i++)
+ slide_switch_unregister_gpios(&pdev->dev,
+ &pdata->gpiolist[i], slide_switch);
+
+ input_unregister_device(slide_switch->input);
+ platform_set_drvdata(pdev, NULL);
+ kfree(slide_switch);
+
+ return 0;
+}
+
+static struct platform_driver slide_switch_driver = {
+ .probe = slide_switch_probe,
+ .remove = __devexit_p(slide_switch_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ }
+};
+
+static int __init slide_switch_init(void)
+{
+ return platform_driver_register(&slide_switch_driver);
+}
+
+static void __exit slide_switch_exit(void)
+{
+ platform_driver_unregister(&slide_switch_driver);
+}
+
+module_init(slide_switch_init);
+module_exit(slide_switch_exit);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_DESCRIPTION("GPIO slide switch driver");
+MODULE_AUTHOR("Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+
diff --git a/include/linux/input/slide_switch.h b/include/linux/input/slide_switch.h
new file mode 100644
index 0000000..b7544cb
--- /dev/null
+++ b/include/linux/input/slide_switch.h
@@ -0,0 +1,16 @@
+#ifndef __SLIDE_SWITCH_H__
+#define __SLIDE_SWITCH_H__
+
+struct slide_switch_gpio {
+ unsigned int gpio;
+ unsigned int inverted;
+};
+
+struct slide_switch_platform_data {
+ unsigned int axis;
+ const struct slide_switch_gpio *gpiolist;
+ unsigned int gpios;
+ unsigned int debounce_ms;
+};
+
+#endif /* __SLIDE_SWITCH_H__ */
--
1.7.4.1
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