There exist tilt switches that simply report their tilt-state via some gpios.
The number and orientation of their axes can vary depending on the switch
used and the build of the device. Also two or more one-axis switches
could be combined to provide multi-dimensional orientation.
One example of a device using such a switch is the family of Qisda
ebook readers, where the switch provides information about the
landscape / portrait orientation of the device. The example in
Documentation/input/gpio-tilt.txt documents exactly this one-axis device.
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
---
Documentation/input/gpio-tilt.txt | 103 ++++++++++++
drivers/input/misc/Kconfig | 14 ++
drivers/input/misc/Makefile | 1 +
drivers/input/misc/gpio_tilt_polled.c | 276 +++++++++++++++++++++++++++++++++
include/linux/gpio_tilt.h | 73 +++++++++
5 files changed, 467 insertions(+), 0 deletions(-)
create mode 100644 Documentation/input/gpio-tilt.txt
create mode 100644 drivers/input/misc/gpio_tilt_polled.c
create mode 100644 include/linux/gpio_tilt.h
diff --git a/Documentation/input/gpio-tilt.txt b/Documentation/input/gpio-tilt.txt
new file mode 100644
index 0000000..06d60c3
--- /dev/null
+++ b/Documentation/input/gpio-tilt.txt
@@ -0,0 +1,103 @@
+Driver for tilt-switches connected via GPIOs
+============================================
+
+Generic driver to read data from tilt switches connected via gpios.
+Orientation can be provided by one or more than one tilt switches,
+i.e. each tilt switch providing one axis, and the number of axes
+is also not limited.
+
+
+Data structures:
+----------------
+
+The array of struct gpio in the gpios field is used to list the gpios
+that represent the current tilt state.
+
+The array of struct gpio_tilt_axis describes the axes that are reported
+to the input system. The values set therein are used for the
+input_set_abs_params calls needed to init the axes.
+
+The array of struct gpio_tilt_state maps gpio states to the corresponding
+values to report. The gpio state is represented as a bitfield where the
+bit-index corresponds to the index of the gpio in the struct gpio array.
+In the same manner the values stored in the axes array correspond to
+the elements of the gpio_tilt_axis-array.
+
+
+Example:
+--------
+
+Example configuration for a single TS1003 tilt switch that rotates around
+one axis in 4 steps and emitts the current tilt via two GPIOs.
+
+static int sg060_tilt_enable(struct device *dev) {
+ /* code to enable the sensors */
+};
+
+static void sg060_tilt_disable(struct device *dev) {
+ /* code to disable the sensors */
+};
+
+static struct gpio sg060_tilt_gpios[] = {
+ { SG060_TILT_GPIO_SENSOR1, GPIOF_IN, "tilt_sensor1" },
+ { SG060_TILT_GPIO_SENSOR2, GPIOF_IN, "tilt_sensor2" },
+};
+
+static struct gpio_tilt_state sg060_tilt_states[] = {
+ {
+ .gpios = (0 << 1) | (0 << 0),
+ .axes = (int[]) {
+ 0,
+ },
+ }, {
+ .gpios = (0 << 1) | (1 << 0),
+ .axes = (int[]) {
+ 1, /* 90 degrees */
+ },
+ }, {
+ .gpios = (1 << 1) | (1 << 0),
+ .axes = (int[]) {
+ 2, /* 180 degrees */
+ },
+ }, {
+ .gpios = (1 << 1) | (0 << 0),
+ .axes = (int[]) {
+ 3, /* 270 degrees */
+ },
+ },
+};
+
+static struct gpio_tilt_axis sg060_tilt_axes[] = {
+ {
+ .axis = ABS_RY,
+ .min = 0,
+ .max = 3,
+ .fuzz = 0,
+ .flat = 0,
+ },
+};
+
+static struct gpio_tilt_platform_data sg060_tilt_pdata= {
+ .gpios = sg060_tilt_gpios,
+ .nr_gpios = ARRAY_SIZE(sg060_tilt_gpios),
+
+ .axes = sg060_tilt_axes,
+ .nr_axes = ARRAY_SIZE(sg060_tilt_axes),
+
+ .states = sg060_tilt_states,
+ .nr_states = ARRAY_SIZE(sg060_tilt_states),
+
+ .debounce_interval = 100,
+
+ .poll_interval = 1000,
+ .enable = sg060_tilt_enable,
+ .disable = sg060_tilt_disable,
+};
+
+static struct platform_device sg060_device_tilt = {
+ .name = "gpio-tilt-polled",
+ .id = -1,
+ .dev = {
+ .platform_data = &sg060_tilt_pdata,
+ },
+};
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 22d875f..e53b443 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -179,6 +179,20 @@ config INPUT_APANEL
To compile this driver as a module, choose M here: the module will
be called apanel.
+config INPUT_GPIO_TILT_POLLED
+ tristate "Polled GPIO tilt switch"
+ depends on GENERIC_GPIO
+ select INPUT_POLLDEV
+ help
+ This driver implements support for tilt switches connected
+ to GPIO pins that are not capable of generating interrupts.
+
+ The list of gpios to use and the mapping of their states
+ to specific angles is done via platform data.
+
+ To compile this driver as a module, choose M here: the
+ module will be called gpio_tilt_polled.
+
config INPUT_IXP4XX_BEEPER
tristate "IXP4XX Beeper support"
depends on ARCH_IXP4XX
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index a244fc6..90070c1 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_INPUT_CMA3000_I2C) += cma3000_d0x_i2c.o
obj-$(CONFIG_INPUT_COBALT_BTNS) += cobalt_btns.o
obj-$(CONFIG_INPUT_DM355EVM) += dm355evm_keys.o
obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o
+obj-$(CONFIG_INPUT_GPIO_TILT_POLLED) += gpio_tilt_polled.o
obj-$(CONFIG_INPUT_IXP4XX_BEEPER) += ixp4xx-beeper.o
obj-$(CONFIG_INPUT_KEYSPAN_REMOTE) += keyspan_remote.o
obj-$(CONFIG_INPUT_KXTJ9) += kxtj9.o
diff --git a/drivers/input/misc/gpio_tilt_polled.c b/drivers/input/misc/gpio_tilt_polled.c
new file mode 100644
index 0000000..15ab935
--- /dev/null
+++ b/drivers/input/misc/gpio_tilt_polled.c
@@ -0,0 +1,276 @@
+/*
+ * Driver for tilt switches connected via GPIO lines
+ * not capable of generating interrupts
+ *
+ * Copyright (C) 2011 Heiko Stuebner <heiko@xxxxxxxxx>
+ *
+ * based on: /drivers/input/keyboard/gpio_keys_polled.c
+ *
+ * Copyright (C) 2007-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ * Copyright (C) 2010 Nuno Goncalves <nunojpg@xxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/gpio_tilt.h>
+
+#define DRV_NAME "gpio-tilt-polled"
+
+struct gpio_tilt_polled_dev {
+ struct input_polled_dev *poll_dev;
+ struct device *dev;
+
+ struct gpio *gpios;
+ int nr_gpios;
+
+ struct gpio_tilt_state *states;
+ int nr_states;
+
+ int *axes;
+ int nr_axes;
+
+ int last_state;
+
+ int threshold;
+ int count;
+
+ int (*enable)(struct device *dev);
+ void (*disable)(struct device *dev);
+};
+
+static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
+{
+ struct gpio_tilt_polled_dev *bdev = dev->private;
+ struct input_dev *input = dev->input;
+ struct gpio_tilt_state *tilt_state = NULL;
+ int state, i;
+
+ if (bdev->count < bdev->threshold) {
+ bdev->count++;
+ } else {
+ state = 0;
+ for (i = 0; i < bdev->nr_gpios; i++)
+ state |= (!!gpio_get_value(bdev->gpios[i].gpio) << i);
+
+ if (state != bdev->last_state) {
+ for (i = 0; i < bdev->nr_states; i++)
+ if (bdev->states[i].gpios == state)
+ tilt_state = &bdev->states[i];
+
+ if (tilt_state) {
+ for (i = 0; i < bdev->nr_axes; i++)
+ input_report_abs(input, bdev->axes[i],
+ tilt_state->axes[i]);
+
+ input_sync(input);
+ }
+
+ bdev->count = 0;
+ bdev->last_state = state;
+ }
+ }
+}
+
+static void gpio_tilt_polled_open(struct input_polled_dev *dev)
+{
+ struct gpio_tilt_polled_dev *bdev = dev->private;
+
+ if (bdev->enable)
+ bdev->enable(bdev->dev);
+}
+
+static void gpio_tilt_polled_close(struct input_polled_dev *dev)
+{
+ struct gpio_tilt_polled_dev *bdev = dev->private;
+
+ if (bdev->disable)
+ bdev->disable(bdev->dev);
+}
+
+static int __devinit gpio_tilt_polled_probe(struct platform_device *pdev)
+{
+ struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
+ struct device *dev = &pdev->dev;
+ struct gpio_tilt_polled_dev *bdev;
+ struct input_polled_dev *poll_dev;
+ struct input_dev *input;
+ int error, i;
+
+ if (!pdata || !pdata->poll_interval)
+ return -EINVAL;
+
+ bdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
+ if (!bdev) {
+ dev_err(dev, "no memory for private data\n");
+ return -ENOMEM;
+ }
+
+ bdev->gpios = kmemdup(pdata->gpios,
+ pdata->nr_gpios * sizeof(struct gpio),
+ GFP_KERNEL);
+ if (bdev->gpios == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate gpio data\n");
+ error = -ENOMEM;
+ goto err_free_bdev;
+ }
+ bdev->nr_gpios = pdata->nr_gpios;
+
+ error = gpio_request_array(bdev->gpios, bdev->nr_gpios);
+ if (error) {
+ dev_err(dev,
+ "Could not request tilt GPIOs: %d\n", error);
+ goto err_free_gpiomem;
+ }
+
+ bdev->states = kmemdup(pdata->states,
+ pdata->nr_states *
+ sizeof(struct gpio_tilt_state),
+ GFP_KERNEL);
+ if (bdev->states == NULL) {
+ dev_err(dev, "Failed to allocate state data\n");
+ error = -ENOMEM;
+ goto err_free_gpios;
+ }
+ bdev->nr_states = pdata->nr_states;
+
+ bdev->axes = kzalloc(pdata->nr_axes * sizeof(int), GFP_KERNEL);
+ if (!bdev->axes) {
+ dev_err(dev, "no memory for axes data\n");
+ error = -ENOMEM;
+ goto err_free_states;
+ }
+
+ poll_dev = input_allocate_polled_device();
+ if (!poll_dev) {
+ dev_err(dev, "no memory for polled device\n");
+ error = -ENOMEM;
+ goto err_free_axes;
+ }
+
+ poll_dev->private = bdev;
+ poll_dev->poll = gpio_tilt_polled_poll;
+ poll_dev->poll_interval = pdata->poll_interval;
+ poll_dev->open = gpio_tilt_polled_open;
+ poll_dev->close = gpio_tilt_polled_close;
+
+ input = poll_dev->input;
+
+ input->name = pdev->name;
+ input->phys = DRV_NAME"/input0";
+ input->dev.parent = &pdev->dev;
+
+ input->id.bustype = BUS_HOST;
+ input->id.vendor = 0x0001;
+ input->id.product = 0x0001;
+ input->id.version = 0x0100;
+
+ __set_bit(EV_ABS, input->evbit);
+ for (i = 0; i < pdata->nr_axes; i++) {
+ input_set_abs_params(input, pdata->axes[i].axis,
+ pdata->axes[i].min, pdata->axes[i].max,
+ pdata->axes[i].fuzz, pdata->axes[i].flat);
+
+ bdev->axes[i] = pdata->axes[i].axis;
+ }
+ bdev->nr_axes = pdata->nr_axes;
+
+ bdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
+ pdata->poll_interval);
+
+ bdev->poll_dev = poll_dev;
+ bdev->dev = dev;
+
+ bdev->enable = pdata->enable;
+ bdev->disable = pdata->disable;
+
+ error = input_register_polled_device(poll_dev);
+ if (error) {
+ dev_err(dev, "unable to register polled device, err=%d\n",
+ error);
+ goto err_free_polldev;
+ }
+
+ platform_set_drvdata(pdev, bdev);
+
+ /* report initial state of the buttons */
+ bdev->last_state = -1;
+ bdev->count = bdev->threshold;
+ gpio_tilt_polled_poll(poll_dev);
+
+ return 0;
+
+err_free_polldev:
+ input_free_polled_device(poll_dev);
+err_free_axes:
+ kfree(bdev->axes);
+err_free_states:
+ kfree(bdev->states);
+err_free_gpios:
+ gpio_free_array(bdev->gpios, bdev->nr_gpios);
+err_free_gpiomem:
+ kfree(bdev->gpios);
+err_free_bdev:
+ kfree(bdev);
+
+ return error;
+}
+
+static int __devexit gpio_tilt_polled_remove(struct platform_device *pdev)
+{
+ struct gpio_tilt_polled_dev *bdev = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+
+ input_unregister_polled_device(bdev->poll_dev);
+ input_free_polled_device(bdev->poll_dev);
+
+ kfree(bdev->axes);
+
+ kfree(bdev->states);
+
+ gpio_free_array(bdev->gpios, bdev->nr_gpios);
+
+ kfree(bdev->gpios);
+
+ kfree(bdev);
+
+ return 0;
+}
+
+static struct platform_driver gpio_tilt_polled_driver = {
+ .probe = gpio_tilt_polled_probe,
+ .remove = __devexit_p(gpio_tilt_polled_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init gpio_tilt_polled_init(void)
+{
+ return platform_driver_register(&gpio_tilt_polled_driver);
+}
+
+static void __exit gpio_tilt_polled_exit(void)
+{
+ platform_driver_unregister(&gpio_tilt_polled_driver);
+}
+
+module_init(gpio_tilt_polled_init);
+module_exit(gpio_tilt_polled_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Heiko Stuebner <heiko@xxxxxxxxx>");
+MODULE_DESCRIPTION("Polled GPIO tilt driver");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/gpio_tilt.h b/include/linux/gpio_tilt.h
new file mode 100644
index 0000000..809fe93
--- /dev/null
+++ b/include/linux/gpio_tilt.h
@@ -0,0 +1,73 @@
+#ifndef _GPIO_TILT_H
+#define _GPIO_TILT_H
+
+/**
+ * struct gpio_tilt_axis - Axis used by the tilt switch
+ * @axis: Constant describing the axis, e.g. ABS_X
+ * @min: minimum value for abs_param
+ * @max: maximum value for abs_param
+ * @fuzz: fuzz value for abs_param
+ * @flat: flat value for abs_param
+ */
+struct gpio_tilt_axis {
+ int axis;
+ int min;
+ int max;
+ int fuzz;
+ int flat;
+};
+
+/**
+ * struct gpio_tilt_state - state description
+ * @gpios: bitfield of gpio target-states for the value
+ * @axes: array containing the axes settings for the gpio state
+ * The array indizes must correspond to the axes defined
+ * in platform_data
+ *
+ * This structure describes a supported axis settings
+ * and the necessary gpio-state which represent it.
+ *
+ * The n-th bit in the bitfield describes the state of the n-th GPIO
+ * from the gpios-array defined in gpio_regulator_config below.
+ */
+struct gpio_tilt_state {
+ int gpios;
+ int *axes;
+};
+
+/**
+ * struct gpio_tilt_platform_data
+ * @gpios: Array containing the gpios determining the tilt state
+ * @nr_gpios: Number of gpios
+ * @axes: Array of gpio_tilt_axis descriptions
+ * @nr_axes: Number of axes
+ * @states: Array of gpio_tilt_state entries describing
+ * the gpio state for specific tilts
+ * @nr_states: Number of states available
+ * @debounce_interval: debounce ticks interval in msecs
+ * @poll_interval: polling interval in msecs - for polling driver only
+ * @enable: callback to enable the tilt switch
+ * @disable: callback to disable the tilt switch
+ *
+ * This structure contains gpio-tilt-switch configuration
+ * information that must be passed by platform code to the
+ * gpio-tilt input driver.
+ */
+struct gpio_tilt_platform_data {
+ struct gpio *gpios;
+ int nr_gpios;
+
+ struct gpio_tilt_axis *axes;
+ int nr_axes;
+
+ struct gpio_tilt_state *states;
+ int nr_states;
+
+ int debounce_interval;
+
+ unsigned int poll_interval;
+ int (*enable)(struct device *dev);
+ void (*disable)(struct device *dev);
+};
+
+#endif
--
1.7.5.4
--
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