A set of ABS_MT events with the desired properties is defined. The events
are divided into categories, to allow for partial implementation. The
-minimum set consists of ABS_MT_TOUCH_MAJOR, ABS_MT_POSITION_X and
-ABS_MT_POSITION_Y, which allows for multiple fingers to be tracked. If the
-device supports it, the ABS_MT_WIDTH_MAJOR may be used to provide the size
-of the approaching finger. Anisotropy and direction may be specified with
-ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and ABS_MT_ORIENTATION. The
-ABS_MT_TOOL_TYPE may be used to specify whether the touching tool is a
+minimum set consists of ABS_MT_POSITION_X and ABS_MT_POSITION_Y, which
+allows for multiple fingers to be tracked. If the device supports it, the
+ABS_MT_TOUCH_MAJOR and ABS_MT_WIDTH_MAJOR may be used to provide the size
+of the contact area and approaching finger, respectively.
+
+The TOUCH and WIDTH parameters have a geometrical interpretation; imagine
+looking through a window at someone gently holding a finger against the
+glass. You will see two regions, one inner region consisting of the part
+of the finger actually touching the glass, and one outer region formed by
+the perimeter of the finger. The diameter of the inner region is the
+ABS_MT_TOUCH_MAJOR, the diameter of the outer region is
+ABS_MT_WIDTH_MAJOR. Now imagine the person pressing the finger harder
+against the glass. The inner region will increase, and in general, the
+ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR, which is always smaller than
+unity, is related to the finger pressure. For pressure-based devices,
+ABS_MT_PRESSURE may be used to provide the pressure on the contact area
+instead.
+
+In addition to the MAJOR parameters, the oval shape of the finger can be
+described by adding the MINOR parameters, such that MAJOR and MINOR are the
+major and minor axis of an ellipse. Finally, the orientation of the oval
+shape can be describe with the ORIENTATION parameter.
+
+The ABS_MT_TOOL_TYPE may be used to specify whether the touching tool is a
finger or a pen or something else. Devices with more granular information
may specify general shapes as blobs, i.e., as a sequence of rectangular
shapes grouped together by an ABS_MT_BLOB_ID. Finally, for the few devices
Here is what a minimal event sequence for a two-finger touch would look
like:
- ABS_MT_TOUCH_MAJOR
ABS_MT_POSITION_X
ABS_MT_POSITION_Y
SYN_MT_REPORT
- ABS_MT_TOUCH_MAJOR
ABS_MT_POSITION_X
ABS_MT_POSITION_Y
SYN_MT_REPORT
the notion of pressure. The fingers of the hand and the palm all have
different characteristic widths [1].
+ABS_MT_PRESSURE
+
+The pressure, in arbitrary units, on the contact area. May be used instead
+of TOUCH and WIDTH for pressure-based devices or any device with a spatial
+signal intensity distribution.
+
ABS_MT_ORIENTATION
The orientation of the ellipse. The value should describe a signed quarter
make use of these native identifiers to reduce bandwidth and cpu usage.
+Gestures
+--------
+
+In the specific application of creating gesture events, the TOUCH and WIDTH
+parameters can be used to, e.g., approximate finger pressure or distinguish
+between index finger and thumb. With the addition of the MINOR parameters,
+one can also distinguish between a sweeping finger and a pointing finger,
+and with ORIENTATION, one can detect twisting of fingers.
+
+
Notes
-----
#include <linux/workqueue.h>
#include <linux/spi/spi.h>
#include <linux/i2c.h>
+#include <linux/gpio.h>
#include <linux/spi/ad7879.h>
struct input_dev *input;
struct work_struct work;
struct timer_list timer;
-
+#ifdef CONFIG_GPIOLIB
+ struct gpio_chip gc;
+#endif
struct mutex mutex;
unsigned disabled:1; /* P: mutex */
u8 median;
u16 x_plate_ohms;
u16 pressure_max;
- u16 gpio_init;
u16 cmd_crtl1;
u16 cmd_crtl2;
u16 cmd_crtl3;
- unsigned gpio:1;
};
static int ad7879_read(bus_device *, u8);
static void ad7879_setup(struct ad7879 *ts)
{
- ts->cmd_crtl3 = AD7879_YPLUS_BIT |
- AD7879_XPLUS_BIT |
- AD7879_Z2_BIT |
- AD7879_Z1_BIT |
- AD7879_TEMPMASK_BIT |
- AD7879_AUXVBATMASK_BIT |
- AD7879_GPIOALERTMASK_BIT;
-
- ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
- AD7879_AVG(ts->averaging) |
- AD7879_MFS(ts->median) |
- AD7879_FCD(ts->first_conversion_delay) |
- ts->gpio_init;
-
- ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
- AD7879_ACQ(ts->acquisition_time) |
- AD7879_TMR(ts->pen_down_acc_interval);
-
ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
ad7879_write(ts->bus, AD7879_REG_CTRL3, ts->cmd_crtl3);
ad7879_write(ts->bus, AD7879_REG_CTRL1, ts->cmd_crtl1);
static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
-static ssize_t ad7879_gpio_show(struct device *dev,
- struct device_attribute *attr, char *buf)
+static struct attribute *ad7879_attributes[] = {
+ &dev_attr_disable.attr,
+ NULL
+};
+
+static const struct attribute_group ad7879_attr_group = {
+ .attrs = ad7879_attributes,
+};
+
+#ifdef CONFIG_GPIOLIB
+static int ad7879_gpio_direction_input(struct gpio_chip *chip,
+ unsigned gpio)
{
- struct ad7879 *ts = dev_get_drvdata(dev);
+ struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+ int err;
- return sprintf(buf, "%u\n", ts->gpio);
+ mutex_lock(&ts->mutex);
+ ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
+ err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+ mutex_unlock(&ts->mutex);
+
+ return err;
}
-static ssize_t ad7879_gpio_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
+static int ad7879_gpio_direction_output(struct gpio_chip *chip,
+ unsigned gpio, int level)
{
- struct ad7879 *ts = dev_get_drvdata(dev);
- unsigned long val;
- int error;
+ struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+ int err;
- error = strict_strtoul(buf, 10, &val);
- if (error)
- return error;
+ mutex_lock(&ts->mutex);
+ ts->cmd_crtl2 &= ~AD7879_GPIODIR;
+ ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
+ if (level)
+ ts->cmd_crtl2 |= AD7879_GPIO_DATA;
+ else
+ ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
+
+ err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+ mutex_unlock(&ts->mutex);
+
+ return err;
+}
+
+static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+ struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+ u16 val;
mutex_lock(&ts->mutex);
- ts->gpio = !!val;
- error = ad7879_write(ts->bus, AD7879_REG_CTRL2,
- ts->gpio ?
- ts->cmd_crtl2 & ~AD7879_GPIO_DATA :
- ts->cmd_crtl2 | AD7879_GPIO_DATA);
+ val = ad7879_read(ts->bus, AD7879_REG_CTRL2);
mutex_unlock(&ts->mutex);
- return error ? : count;
+ return !!(val & AD7879_GPIO_DATA);
}
-static DEVICE_ATTR(gpio, 0664, ad7879_gpio_show, ad7879_gpio_store);
+static void ad7879_gpio_set_value(struct gpio_chip *chip,
+ unsigned gpio, int value)
+{
+ struct ad7879 *ts = container_of(chip, struct ad7879, gc);
-static struct attribute *ad7879_attributes[] = {
- &dev_attr_disable.attr,
- &dev_attr_gpio.attr,
- NULL
-};
+ mutex_lock(&ts->mutex);
+ if (value)
+ ts->cmd_crtl2 |= AD7879_GPIO_DATA;
+ else
+ ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
-static const struct attribute_group ad7879_attr_group = {
- .attrs = ad7879_attributes,
-};
+ ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+ mutex_unlock(&ts->mutex);
+}
+
+static int __devinit ad7879_gpio_add(struct device *dev)
+{
+ struct ad7879 *ts = dev_get_drvdata(dev);
+ struct ad7879_platform_data *pdata = dev->platform_data;
+ int ret = 0;
+
+ if (pdata->gpio_export) {
+ ts->gc.direction_input = ad7879_gpio_direction_input;
+ ts->gc.direction_output = ad7879_gpio_direction_output;
+ ts->gc.get = ad7879_gpio_get_value;
+ ts->gc.set = ad7879_gpio_set_value;
+ ts->gc.can_sleep = 1;
+ ts->gc.base = pdata->gpio_base;
+ ts->gc.ngpio = 1;
+ ts->gc.label = "AD7879-GPIO";
+ ts->gc.owner = THIS_MODULE;
+ ts->gc.dev = dev;
+
+ ret = gpiochip_add(&ts->gc);
+ if (ret)
+ dev_err(dev, "failed to register gpio %d\n",
+ ts->gc.base);
+ }
+
+ return ret;
+}
+
+/*
+ * We mark ad7879_gpio_remove inline so there is a chance the code
+ * gets discarded when not needed. We can't do __devinit/__devexit
+ * markup since it is used in both probe and remove methods.
+ */
+static inline void ad7879_gpio_remove(struct device *dev)
+{
+ struct ad7879 *ts = dev_get_drvdata(dev);
+ struct ad7879_platform_data *pdata = dev->platform_data;
+ int ret;
+
+ if (pdata->gpio_export) {
+ ret = gpiochip_remove(&ts->gc);
+ if (ret)
+ dev_err(dev, "failed to remove gpio %d\n",
+ ts->gc.base);
+ }
+}
+#else
+static inline int ad7879_gpio_add(struct device *dev)
+{
+ return 0;
+}
+
+static inline void ad7879_gpio_remove(struct device *dev)
+{
+}
+#endif
static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
{
ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
ts->median = pdata->median;
- if (pdata->gpio_output)
- ts->gpio_init = AD7879_GPIO_EN |
- (pdata->gpio_default ? 0 : AD7879_GPIO_DATA);
- else
- ts->gpio_init = AD7879_GPIO_EN | AD7879_GPIODIR;
-
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&bus->dev));
input_dev->name = "AD7879 Touchscreen";
goto err_free_mem;
}
+ ts->cmd_crtl3 = AD7879_YPLUS_BIT |
+ AD7879_XPLUS_BIT |
+ AD7879_Z2_BIT |
+ AD7879_Z1_BIT |
+ AD7879_TEMPMASK_BIT |
+ AD7879_AUXVBATMASK_BIT |
+ AD7879_GPIOALERTMASK_BIT;
+
+ ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
+ AD7879_AVG(ts->averaging) |
+ AD7879_MFS(ts->median) |
+ AD7879_FCD(ts->first_conversion_delay);
+
+ ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
+ AD7879_ACQ(ts->acquisition_time) |
+ AD7879_TMR(ts->pen_down_acc_interval);
+
ad7879_setup(ts);
err = request_irq(bus->irq, ad7879_irq,
if (err)
goto err_free_irq;
- err = input_register_device(input_dev);
+ err = ad7879_gpio_add(&bus->dev);
if (err)
goto err_remove_attr;
+ err = input_register_device(input_dev);
+ if (err)
+ goto err_remove_gpio;
+
dev_info(&bus->dev, "Rev.%d touchscreen, irq %d\n",
revid >> 8, bus->irq);
return 0;
+err_remove_gpio:
+ ad7879_gpio_remove(&bus->dev);
err_remove_attr:
sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
err_free_irq:
static int __devexit ad7879_destroy(bus_device *bus, struct ad7879 *ts)
{
+ ad7879_gpio_remove(&bus->dev);
ad7879_disable(ts);
sysfs_remove_group(&ts->bus->dev.kobj, &ad7879_attr_group);
free_irq(ts->bus->irq, ts);
projects / linux-2.6.git / commitdiff