Hi Heiko,
On Fri, Oct 21, 2011 at 10:43:47AM +0200, 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.
>
Looks very nice, just a few comments below.
> 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;
Call it tdev or tilt or tilt_dev or something? bdev is not very fitting
here.
> + 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;
Do you actually need to do this? Can't you just store the pointer to
the platform data and use it instead? Same goes for the rest of items
you are cloning.
> +
> + 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);
This should probably be in gpio_tilt_polled_open().
> +
> + 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
>
Thanks.
--
Dmitry
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