[PATCH v3] Add generic GPIO-tilt driver

[PATCH v3] Add generic GPIO-tilt driver

[Heiko Stübner]

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@sntech.de>
---
changes since v2: use module_platform_driver
changes since v1: address comments from Dmitry Torokhov
* bdev -> tdev
* report initial axis state during open and not during probe
* don't clone platform data and use the original instead

 Documentation/input/gpio-tilt.txt     |  103 ++++++++++++++++
 drivers/input/misc/Kconfig            |   14 ++
 drivers/input/misc/Makefile           |    1 +
 drivers/input/misc/gpio_tilt_polled.c |  214 +++++++++++++++++++++++++++++++++
 include/linux/gpio_tilt.h             |   73 +++++++++++
 5 files changed, 405 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..ebc3f08
--- /dev/null
+++ b/drivers/input/misc/gpio_tilt_polled.c
@@ -0,0 +1,214 @@
+/*
+ *  Driver for tilt switches connected via GPIO lines
+ *  not capable of generating interrupts
+ *
+ *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
+ *
+ *  based on: /drivers/input/keyboard/gpio_keys_polled.c
+ *
+ *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
+ *
+ *  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_tilt_platform_data *pdata;
+
+	int last_state;
+
+	int threshold;
+	int count;
+};
+
+static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
+{
+	struct gpio_tilt_polled_dev *tdev = dev->private;
+	struct gpio_tilt_platform_data *pdata = tdev->pdata;
+	struct input_dev *input = dev->input;
+	struct gpio_tilt_state *tilt_state = NULL;
+	int state, i;
+
+	if (tdev->count < tdev->threshold) {
+		tdev->count++;
+	} else {
+		state = 0;
+		for (i = 0; i < pdata->nr_gpios; i++)
+			state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
+
+		if (state != tdev->last_state) {
+			for (i = 0; i < pdata->nr_states; i++)
+				if (pdata->states[i].gpios == state)
+					tilt_state = &pdata->states[i];
+
+			if (tilt_state) {
+				for (i = 0; i < pdata->nr_axes; i++)
+					input_report_abs(input,
+							 pdata->axes[i].axis,
+							 tilt_state->axes[i]);
+
+				input_sync(input);
+			}
+
+			tdev->count = 0;
+			tdev->last_state = state;
+		}
+	}
+}
+
+static void gpio_tilt_polled_open(struct input_polled_dev *dev)
+{
+	struct gpio_tilt_polled_dev *tdev = dev->private;
+	struct gpio_tilt_platform_data *pdata = tdev->pdata;
+
+	if (pdata->enable)
+		pdata->enable(tdev->dev);
+
+	/* report initial state of the axes */
+	tdev->last_state = -1;
+	tdev->count = tdev->threshold;
+	gpio_tilt_polled_poll(tdev->poll_dev);
+}
+
+static void gpio_tilt_polled_close(struct input_polled_dev *dev)
+{
+	struct gpio_tilt_polled_dev *tdev = dev->private;
+	struct gpio_tilt_platform_data *pdata = tdev->pdata;
+
+	if (pdata->disable)
+		pdata->disable(tdev->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 *tdev;
+	struct input_polled_dev *poll_dev;
+	struct input_dev *input;
+	int error, i;
+
+	if (!pdata || !pdata->poll_interval)
+		return -EINVAL;
+
+	tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
+	if (!tdev) {
+		dev_err(dev, "no memory for private data\n");
+		return -ENOMEM;
+	}
+
+	error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
+	if (error) {
+		dev_err(dev,
+		   "Could not request tilt GPIOs: %d\n", error);
+		goto err_free_tdev;
+	}
+
+	poll_dev = input_allocate_polled_device();
+	if (!poll_dev) {
+		dev_err(dev, "no memory for polled device\n");
+		error = -ENOMEM;
+		goto err_free_gpios;
+	}
+
+	poll_dev->private = tdev;
+	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);
+	}
+
+	tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
+				       pdata->poll_interval);
+
+	tdev->poll_dev = poll_dev;
+	tdev->dev = dev;
+	tdev->pdata = pdata;
+
+	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, tdev);
+
+	return 0;
+
+err_free_polldev:
+	input_free_polled_device(poll_dev);
+err_free_gpios:
+	gpio_free_array(pdata->gpios, pdata->nr_gpios);
+err_free_tdev:
+	kfree(tdev);
+
+	return error;
+}
+
+static int __devexit gpio_tilt_polled_remove(struct platform_device *pdev)
+{
+	struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
+	struct gpio_tilt_platform_data *pdata = tdev->pdata;
+
+	platform_set_drvdata(pdev, NULL);
+
+	input_unregister_polled_device(tdev->poll_dev);
+	input_free_polled_device(tdev->poll_dev);
+
+	gpio_free_array(pdata->gpios, pdata->nr_gpios);
+
+	kfree(tdev);
+
+	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,
+	},
+};
+
+module_platform_driver(gpio_tilt_polled_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+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

Re: [PATCH v3] Add generic GPIO-tilt driver

[Shubhrajyoti Datta]

Hi Heiko,

On Tue, Nov 29, 2011 at 5:54 PM, Heiko Stübner <heiko@sntech.de> wrote:
> 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@sntech.de>
> ---
> changes since v2: use module_platform_driver
> changes since v1: address comments from Dmitry Torokhov
> * bdev -> tdev
> * report initial axis state during open and not during probe
> * don't clone platform data and use the original instead
>
>  Documentation/input/gpio-tilt.txt     |  103 ++++++++++++++++
>  drivers/input/misc/Kconfig            |   14 ++
>  drivers/input/misc/Makefile           |    1 +
>  drivers/input/misc/gpio_tilt_polled.c |  214 +++++++++++++++++++++++++++++++++
>  include/linux/gpio_tilt.h             |   73 +++++++++++
>  5 files changed, 405 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..ebc3f08
> --- /dev/null
> +++ b/drivers/input/misc/gpio_tilt_polled.c
> @@ -0,0 +1,214 @@
> +/*
> + *  Driver for tilt switches connected via GPIO lines
> + *  not capable of generating interrupts
> + *
> + *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
> + *
> + *  based on: /drivers/input/keyboard/gpio_keys_polled.c
> + *
> + *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
> + *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
> + *
> + *  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_tilt_platform_data *pdata;
> +
> +       int last_state;
> +
> +       int threshold;
> +       int count;
> +};
> +
> +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
> +{
> +       struct gpio_tilt_polled_dev *tdev = dev->private;
> +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> +       struct input_dev *input = dev->input;
> +       struct gpio_tilt_state *tilt_state = NULL;
> +       int state, i;
> +
> +       if (tdev->count < tdev->threshold) {
Nitpick : the braces are not necessary.
> +               tdev->count++;
> +       } else {
> +               state = 0;
> +               for (i = 0; i < pdata->nr_gpios; i++)
> +                       state |= (!!gpio_get_value(pdata->gpios[i].gpio) << i);
> +
> +               if (state != tdev->last_state) {
> +                       for (i = 0; i < pdata->nr_states; i++)
> +                               if (pdata->states[i].gpios == state)
> +                                       tilt_state = &pdata->states[i];
> +
> +                       if (tilt_state) {
> +                               for (i = 0; i < pdata->nr_axes; i++)
> +                                       input_report_abs(input,
> +                                                        pdata->axes[i].axis,
> +                                                        tilt_state->axes[i]);
> +
> +                               input_sync(input);
> +                       }
> +
> +                       tdev->count = 0;
> +                       tdev->last_state = state;
> +               }
> +       }
> +}
> +
> +static void gpio_tilt_polled_open(struct input_polled_dev *dev)
> +{
> +       struct gpio_tilt_polled_dev *tdev = dev->private;
> +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> +
> +       if (pdata->enable)
> +               pdata->enable(tdev->dev);
> +
> +       /* report initial state of the axes */
> +       tdev->last_state = -1;
> +       tdev->count = tdev->threshold;
> +       gpio_tilt_polled_poll(tdev->poll_dev);
> +}
> +
> +static void gpio_tilt_polled_close(struct input_polled_dev *dev)
> +{
> +       struct gpio_tilt_polled_dev *tdev = dev->private;
> +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> +
> +       if (pdata->disable)
> +               pdata->disable(tdev->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 *tdev;
> +       struct input_polled_dev *poll_dev;
> +       struct input_dev *input;
> +       int error, i;
> +
> +       if (!pdata || !pdata->poll_interval)
> +               return -EINVAL;
Could we have a default poll interval if passed 0 ?
Feel free to ignore if you feel otherwise.

> +
> +       tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
> +       if (!tdev) {
> +               dev_err(dev, "no memory for private data\n");
> +               return -ENOMEM;
> +       }
> +
> +       error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
> +       if (error) {
> +               dev_err(dev,
> +                  "Could not request tilt GPIOs: %d\n", error);
> +               goto err_free_tdev;
> +       }
> +
> +       poll_dev = input_allocate_polled_device();
> +       if (!poll_dev) {
> +               dev_err(dev, "no memory for polled device\n");
> +               error = -ENOMEM;
> +               goto err_free_gpios;
> +       }
> +
> +       poll_dev->private = tdev;
> +       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);
> +       }
> +
> +       tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
> +                                      pdata->poll_interval);
> +
> +       tdev->poll_dev = poll_dev;
> +       tdev->dev = dev;
> +       tdev->pdata = pdata;
> +
> +       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, tdev);
> +
> +       return 0;
> +
> +err_free_polldev:
> +       input_free_polled_device(poll_dev);
> +err_free_gpios:
> +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
> +err_free_tdev:
> +       kfree(tdev);
> +
> +       return error;
> +}
> +
> +static int __devexit gpio_tilt_polled_remove(struct platform_device *pdev)
> +{
> +       struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
> +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> +
> +       platform_set_drvdata(pdev, NULL);
> +
> +       input_unregister_polled_device(tdev->poll_dev);
> +       input_free_polled_device(tdev->poll_dev);
> +
> +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
> +
> +       kfree(tdev);
> +
> +       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,
> +       },
> +};
> +
> +module_platform_driver(gpio_tilt_polled_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
> +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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Re: [PATCH v3] Add generic GPIO-tilt driver

[Heiko Stübner]

Hi Shubhrajyoti,

Am Dienstag, 29. November 2011, 15:59:29 schrieb Shubhrajyoti Datta:
> Hi Heiko,
> 
> On Tue, Nov 29, 2011 at 5:54 PM, Heiko Stübner <heiko@sntech.de> wrote:
> > 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@sntech.de>
> > ---
> > changes since v2: use module_platform_driver
> > changes since v1: address comments from Dmitry Torokhov
> > * bdev -> tdev
> > * report initial axis state during open and not during probe
> > * don't clone platform data and use the original instead
> > 
> >  Documentation/input/gpio-tilt.txt     |  103 ++++++++++++++++
> >  drivers/input/misc/Kconfig            |   14 ++
> >  drivers/input/misc/Makefile           |    1 +
> >  drivers/input/misc/gpio_tilt_polled.c |  214
> > +++++++++++++++++++++++++++++++++ include/linux/gpio_tilt.h            
> > |   73 +++++++++++
> >  5 files changed, 405 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..ebc3f08
> > --- /dev/null
> > +++ b/drivers/input/misc/gpio_tilt_polled.c
> > @@ -0,0 +1,214 @@
> > +/*
> > + *  Driver for tilt switches connected via GPIO lines
> > + *  not capable of generating interrupts
> > + *
> > + *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
> > + *
> > + *  based on: /drivers/input/keyboard/gpio_keys_polled.c
> > + *
> > + *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
> > + *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
> > + *
> > + *  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_tilt_platform_data *pdata;
> > +
> > +       int last_state;
> > +
> > +       int threshold;
> > +       int count;
> > +};
> > +
> > +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
> > +{
> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> > +       struct input_dev *input = dev->input;
> > +       struct gpio_tilt_state *tilt_state = NULL;
> > +       int state, i;
> > +
> > +       if (tdev->count < tdev->threshold) {
> 
> Nitpick : the braces are not necessary.
hmm ... for me it's easier to read if the style of the braces does not change
between if and else, i.e. both with or without braces.
And the kernel CodingStyle-file seems also to be in my favor ;-)
[starting from line 169].

> > +               tdev->count++;
> > +       } else {
> > +               state = 0;
> > +               for (i = 0; i < pdata->nr_gpios; i++)
> > +                       state |= (!!gpio_get_value(pdata->gpios[i].gpio)
> > << i); +
> > +               if (state != tdev->last_state) {
> > +                       for (i = 0; i < pdata->nr_states; i++)
> > +                               if (pdata->states[i].gpios == state)
> > +                                       tilt_state = &pdata->states[i];
> > +
> > +                       if (tilt_state) {
> > +                               for (i = 0; i < pdata->nr_axes; i++)
> > +                                       input_report_abs(input,
> > +                                                      
> >  pdata->axes[i].axis, +                                                
> >        tilt_state->axes[i]); +
> > +                               input_sync(input);
> > +                       }
> > +
> > +                       tdev->count = 0;
> > +                       tdev->last_state = state;
> > +               }
> > +       }
> > +}
> > +
> > +static void gpio_tilt_polled_open(struct input_polled_dev *dev)
> > +{
> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> > +
> > +       if (pdata->enable)
> > +               pdata->enable(tdev->dev);
> > +
> > +       /* report initial state of the axes */
> > +       tdev->last_state = -1;
> > +       tdev->count = tdev->threshold;
> > +       gpio_tilt_polled_poll(tdev->poll_dev);
> > +}
> > +
> > +static void gpio_tilt_polled_close(struct input_polled_dev *dev)
> > +{
> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> > +
> > +       if (pdata->disable)
> > +               pdata->disable(tdev->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 *tdev;
> > +       struct input_polled_dev *poll_dev;
> > +       struct input_dev *input;
> > +       int error, i;
> > +
> > +       if (!pdata || !pdata->poll_interval)
> > +               return -EINVAL;
> 
> Could we have a default poll interval if passed 0 ?
> Feel free to ignore if you feel otherwise.
For me either way is fine but I'm not sure what would be a generic
enough default value for most cases (500, 1000 ? ).

> > +
> > +       tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
> > +       if (!tdev) {
> > +               dev_err(dev, "no memory for private data\n");
> > +               return -ENOMEM;
> > +       }
> > +
> > +       error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
> > +       if (error) {
> > +               dev_err(dev,
> > +                  "Could not request tilt GPIOs: %d\n", error);
> > +               goto err_free_tdev;
> > +       }
> > +
> > +       poll_dev = input_allocate_polled_device();
> > +       if (!poll_dev) {
> > +               dev_err(dev, "no memory for polled device\n");
> > +               error = -ENOMEM;
> > +               goto err_free_gpios;
> > +       }
> > +
> > +       poll_dev->private = tdev;
> > +       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); +       }
> > +
> > +       tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
> > +                                      pdata->poll_interval);
> > +
> > +       tdev->poll_dev = poll_dev;
> > +       tdev->dev = dev;
> > +       tdev->pdata = pdata;
> > +
> > +       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, tdev);
> > +
> > +       return 0;
> > +
> > +err_free_polldev:
> > +       input_free_polled_device(poll_dev);
> > +err_free_gpios:
> > +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
> > +err_free_tdev:
> > +       kfree(tdev);
> > +
> > +       return error;
> > +}
> > +
> > +static int __devexit gpio_tilt_polled_remove(struct platform_device
> > *pdev) +{
> > +       struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> > +
> > +       platform_set_drvdata(pdev, NULL);
> > +
> > +       input_unregister_polled_device(tdev->poll_dev);
> > +       input_free_polled_device(tdev->poll_dev);
> > +
> > +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
> > +
> > +       kfree(tdev);
> > +
> > +       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,
> > +       },
> > +};
> > +
> > +module_platform_driver(gpio_tilt_polled_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
> > +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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Re: [PATCH v3] Add generic GPIO-tilt driver

[Shubhrajyoti Datta]

On Tue, Nov 29, 2011 at 8:42 PM, Heiko Stübner <heiko@sntech.de> wrote:
> Hi Shubhrajyoti,
>
> Am Dienstag, 29. November 2011, 15:59:29 schrieb Shubhrajyoti Datta:
>> Hi Heiko,
>>
>> On Tue, Nov 29, 2011 at 5:54 PM, Heiko Stübner <heiko@sntech.de> wrote:
>> > 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@sntech.de>
>> > ---
>> > changes since v2: use module_platform_driver
>> > changes since v1: address comments from Dmitry Torokhov
>> > * bdev -> tdev
>> > * report initial axis state during open and not during probe
>> > * don't clone platform data and use the original instead
>> >
>> >  Documentation/input/gpio-tilt.txt     |  103 ++++++++++++++++
>> >  drivers/input/misc/Kconfig            |   14 ++
>> >  drivers/input/misc/Makefile           |    1 +
>> >  drivers/input/misc/gpio_tilt_polled.c |  214
>> > +++++++++++++++++++++++++++++++++ include/linux/gpio_tilt.h
>> > |   73 +++++++++++
>> >  5 files changed, 405 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..ebc3f08
>> > --- /dev/null
>> > +++ b/drivers/input/misc/gpio_tilt_polled.c
>> > @@ -0,0 +1,214 @@
>> > +/*
>> > + *  Driver for tilt switches connected via GPIO lines
>> > + *  not capable of generating interrupts
>> > + *
>> > + *  Copyright (C) 2011 Heiko Stuebner <heiko@sntech.de>
>> > + *
>> > + *  based on: /drivers/input/keyboard/gpio_keys_polled.c
>> > + *
>> > + *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
>> > + *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
>> > + *
>> > + *  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_tilt_platform_data *pdata;
>> > +
>> > +       int last_state;
>> > +
>> > +       int threshold;
>> > +       int count;
>> > +};
>> > +
>> > +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
>> > +{
>> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
>> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +       struct input_dev *input = dev->input;
>> > +       struct gpio_tilt_state *tilt_state = NULL;
>> > +       int state, i;
>> > +
>> > +       if (tdev->count < tdev->threshold) {
>>
>> Nitpick : the braces are not necessary.
> hmm ... for me it's easier to read if the style of the braces does not change
> between if and else, i.e. both with or without braces.
> And the kernel CodingStyle-file seems also to be in my favor ;-)
> [starting from line 169].

I see thanks for correcting.
>
>> > +               tdev->count++;
>> > +       } else {
>> > +               state = 0;
>> > +               for (i = 0; i < pdata->nr_gpios; i++)
>> > +                       state |= (!!gpio_get_value(pdata->gpios[i].gpio)
>> > << i); +
>> > +               if (state != tdev->last_state) {
>> > +                       for (i = 0; i < pdata->nr_states; i++)
>> > +                               if (pdata->states[i].gpios == state)
>> > +                                       tilt_state = &pdata->states[i];
>> > +
>> > +                       if (tilt_state) {
>> > +                               for (i = 0; i < pdata->nr_axes; i++)
>> > +                                       input_report_abs(input,
>> > +
>> >  pdata->axes[i].axis, +
>> >        tilt_state->axes[i]); +
>> > +                               input_sync(input);
>> > +                       }
>> > +
>> > +                       tdev->count = 0;
>> > +                       tdev->last_state = state;
>> > +               }
>> > +       }
>> > +}
>> > +
>> > +static void gpio_tilt_polled_open(struct input_polled_dev *dev)
>> > +{
>> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
>> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > +       if (pdata->enable)
>> > +               pdata->enable(tdev->dev);
>> > +
>> > +       /* report initial state of the axes */
>> > +       tdev->last_state = -1;
>> > +       tdev->count = tdev->threshold;
>> > +       gpio_tilt_polled_poll(tdev->poll_dev);
>> > +}
>> > +
>> > +static void gpio_tilt_polled_close(struct input_polled_dev *dev)
>> > +{
>> > +       struct gpio_tilt_polled_dev *tdev = dev->private;
>> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > +       if (pdata->disable)
>> > +               pdata->disable(tdev->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 *tdev;
>> > +       struct input_polled_dev *poll_dev;
>> > +       struct input_dev *input;
>> > +       int error, i;
>> > +
>> > +       if (!pdata || !pdata->poll_interval)
>> > +               return -EINVAL;
>>
>> Could we have a default poll interval if passed 0 ?
>> Feel free to ignore if you feel otherwise.
> For me either way is fine but I'm not sure what would be a generic
> enough default value for most cases (500, 1000 ? ).
>
I was thinking that just because someone doesn't populate the timeout gets
penalised max ie failure of probe.

1000 looks good to me also your documentation suggests so . However I leave the
decision to you.

>> > +
>> > +       tdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
>> > +       if (!tdev) {
>> > +               dev_err(dev, "no memory for private data\n");
>> > +               return -ENOMEM;
>> > +       }
>> > +
>> > +       error = gpio_request_array(pdata->gpios, pdata->nr_gpios);
>> > +       if (error) {
>> > +               dev_err(dev,
>> > +                  "Could not request tilt GPIOs: %d\n", error);
>> > +               goto err_free_tdev;
>> > +       }
>> > +
>> > +       poll_dev = input_allocate_polled_device();
>> > +       if (!poll_dev) {
>> > +               dev_err(dev, "no memory for polled device\n");
>> > +               error = -ENOMEM;
>> > +               goto err_free_gpios;
>> > +       }
>> > +
>> > +       poll_dev->private = tdev;
>> > +       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); +       }
>> > +
>> > +       tdev->threshold = DIV_ROUND_UP(pdata->debounce_interval,
>> > +                                      pdata->poll_interval);
>> > +
>> > +       tdev->poll_dev = poll_dev;
>> > +       tdev->dev = dev;
>> > +       tdev->pdata = pdata;
>> > +
>> > +       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, tdev);
>> > +
>> > +       return 0;
>> > +
>> > +err_free_polldev:
>> > +       input_free_polled_device(poll_dev);
>> > +err_free_gpios:
>> > +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
>> > +err_free_tdev:
>> > +       kfree(tdev);
>> > +
>> > +       return error;
>> > +}
>> > +
>> > +static int __devexit gpio_tilt_polled_remove(struct platform_device
>> > *pdev) +{
>> > +       struct gpio_tilt_polled_dev *tdev = platform_get_drvdata(pdev);
>> > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
>> > +
>> > +       platform_set_drvdata(pdev, NULL);
>> > +
>> > +       input_unregister_polled_device(tdev->poll_dev);
>> > +       input_free_polled_device(tdev->poll_dev);
>> > +
>> > +       gpio_free_array(pdata->gpios, pdata->nr_gpios);
>> > +
>> > +       kfree(tdev);
>> > +
>> > +       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,
>> > +       },
>> > +};
>> > +
>> > +module_platform_driver(gpio_tilt_polled_driver);
>> > +
>> > +MODULE_LICENSE("GPL v2");
>> > +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
>> > +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
>> >
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-input" in
>> > the body of a message to majordomo@vger.kernel.org
>> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>> --
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>
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Re: [PATCH v3] Add generic GPIO-tilt driver

[Dmitry Torokhov]

On Tue, Nov 29, 2011 at 01:24:33PM +0100, Heiko Stübner wrote:
> 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@sntech.de>
> ---
> changes since v2: use module_platform_driver

Could you please separate this change? I applied previous version to my
tree and I am not sure when module_driver changes will hit mainline...

Thanks.

-- 
Dmitry
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Re: [PATCH v3] Add generic GPIO-tilt driver

[Dmitry Torokhov]

On Tue, Nov 29, 2011 at 04:12:40PM +0100, Heiko Stübner wrote:
> Hi Shubhrajyoti,
> 
> Am Dienstag, 29. November 2011, 15:59:29 schrieb Shubhrajyoti Datta:
> > Hi Heiko,
> > 
> > On Tue, Nov 29, 2011 at 5:54 PM, Heiko Stübner <heiko@sntech.de> wrote:
> > > +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
> > > +{
> > > +       struct gpio_tilt_polled_dev *tdev = dev->private;
> > > +       struct gpio_tilt_platform_data *pdata = tdev->pdata;
> > > +       struct input_dev *input = dev->input;
> > > +       struct gpio_tilt_state *tilt_state = NULL;
> > > +       int state, i;
> > > +
> > > +       if (tdev->count < tdev->threshold) {
> > 
> > Nitpick : the braces are not necessary.
> hmm ... for me it's easier to read if the style of the braces does not change
> between if and else, i.e. both with or without braces.
> And the kernel CodingStyle-file seems also to be in my favor ;-)
> [starting from line 169].

Yep, when one branch requires braces it is preferred to have then on
all branches.

> > > +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 *tdev;
> > > +       struct input_polled_dev *poll_dev;
> > > +       struct input_dev *input;
> > > +       int error, i;
> > > +
> > > +       if (!pdata || !pdata->poll_interval)
> > > +               return -EINVAL;
> > 
> > Could we have a default poll interval if passed 0 ?
> > Feel free to ignore if you feel otherwise.
> For me either way is fine but I'm not sure what would be a generic
> enough default value for most cases (500, 1000 ? ).
> 

I'd rather error out then give default which we can't sanely select.
Then platform integrator will be alerted early and select appropriate
value.

Thanks.

-- 
Dmitry
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Re: [PATCH v3] Add generic GPIO-tilt driver

[Mark Brown]

On Tue, Nov 29, 2011 at 10:23:26AM -0800, Dmitry Torokhov wrote:

> Could you please separate this change? I applied previous version to my
> tree and I am not sure when module_driver changes will hit mainline...

module_platform_driver is in Linus' tree already.

Re: [PATCH v3] Add generic GPIO-tilt driver

[Dmitry Torokhov]

On Tue, Nov 29, 2011 at 06:42:03PM +0000, Mark Brown wrote:
> On Tue, Nov 29, 2011 at 10:23:26AM -0800, Dmitry Torokhov wrote:
> 
> > Could you please separate this change? I applied previous version to my
> > tree and I am not sure when module_driver changes will hit mainline...
> 
> module_platform_driver is in Linus' tree already.

Ah, indeed, its the rest of the buses that are missing. Anyway, could I
still get a separate patch, please?

-- 
Dmitry

Re: [PATCH v3] Add generic GPIO-tilt driver

[Dmitry Torokhov]

On Tue, Nov 29, 2011 at 10:56:23AM -0800, Dmitry Torokhov wrote:
> On Tue, Nov 29, 2011 at 06:42:03PM +0000, Mark Brown wrote:
> > On Tue, Nov 29, 2011 at 10:23:26AM -0800, Dmitry Torokhov wrote:
> > 
> > > Could you please separate this change? I applied previous version to my
> > > tree and I am not sure when module_driver changes will hit mainline...
> > 
> > module_platform_driver is in Linus' tree already.
> 
> Ah, indeed, its the rest of the buses that are missing. Anyway, could I
> still get a separate patch, please?
> 

Ah, never mind, I haven't pushed it out yet so I'll take the latest
version.

-- 
Dmitry

Re: [PATCH v3] Add generic GPIO-tilt driver

[Heiko Stübner]

Am Dienstag 29 November 2011, 20:06:02 schrieb Dmitry Torokhov:
> On Tue, Nov 29, 2011 at 10:56:23AM -0800, Dmitry Torokhov wrote:
> > On Tue, Nov 29, 2011 at 06:42:03PM +0000, Mark Brown wrote:
> > > On Tue, Nov 29, 2011 at 10:23:26AM -0800, Dmitry Torokhov wrote:
> > > > Could you please separate this change? I applied previous version to
> > > > my tree and I am not sure when module_driver changes will hit
> > > > mainline...
> > > 
> > > module_platform_driver is in Linus' tree already.
> > 
> > Ah, indeed, its the rest of the buses that are missing. Anyway, could I
> > still get a separate patch, please?
> 
> Ah, never mind, I haven't pushed it out yet so I'll take the latest
> version.
very cool :-)

Thanks
Heiko