前言：在qualcomm平台中，具有触摸屏、轨迹球和简单按键功能，这些功能是由安卓系统中的驱动程序实现的，并且需要用户空间的内容来协助实现。输入系统设备包括一下event设备。
/dev/input/event4:几个按键设备
/dev/input/event2:触摸屏设备
/dev/input/event5：轨迹球设备
一、触摸屏驱动
qualcomm平台的触摸屏驱动程序的实现文件是drivers/input/touchscreen/synaptics_i2c_rmi.c，此文件的核心是函数synaptics_ts_probe(),在该函数中需要进行触摸屏工作的初始化，对作为输入设备的触摸屏驱动在Linux平台下的设备名注册，同事初始化触摸事件出发时引起的中断操作。此函数的实现代码如下多事。
/**
* synaptics_rmi4_probe()
*
* Called by the kernel when an association with an I2C device of the
* same name is made (after doing i2c_add_driver).
*
* This function allocates and initializes the resources for the driver
* as an input driver, turns on the power to the sensor, queries the
* sensor for its supported Functions and characteristics, registers
* the driver to the input subsystem, sets up the interrupt, handles
* the registration of the early_suspend and late_resume functions,
* and creates a work queue for detection of other expansion Function
* modules.
*/
static int synaptics_rmi4_probe(struct i2c_client *client,
const struct i2c_device_id *dev_id)
{
int retval = 0;
unsigned char ii;
unsigned char attr_count;
struct synaptics_rmi4_f1a_handle *f1a;
struct synaptics_rmi4_fn *fhandler;
struct synaptics_rmi4_fn *next_fhandler;
struct synaptics_rmi4_data *rmi4_data;
struct synaptics_rmi4_device_info *rmi;
struct synaptics_rmi4_platform_data *platform_data =
client->dev.platform_data;
struct dentry *temp;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA)) {
dev_err(&client->dev,
"%s: SMBus byte data not supportedn",
__func__);
return -EIO;
}
if (client->dev.of_node) {
platform_data = devm_kzalloc(&client->dev,
sizeof(*platform_data),
GFP_KERNEL);
if (!platform_data) {
dev_err(&client->dev, "Failed to allocate memoryn");
return -ENOMEM;
}
retval = synaptics_rmi4_parse_dt(&client->dev, platform_data);
if (retval)
return retval;
} else {
platform_data = client->dev.platform_data;
}
if (!platform_data) {
dev_err(&client->dev,
"%s: No platform data foundn",
__func__);
return -EINVAL;
}
rmi4_data = kzalloc(sizeof(*rmi4_data) * 2, GFP_KERNEL);
if (!rmi4_data)
return -ENOMEM;
rmi = &(rmi4_data->rmi4_mod_info);
//创建设备 rmi4_data->input_dev = input_allocate_device();
if (rmi4_data->input_dev == NULL) {
retval = -ENOMEM;
goto err_input_device;
}
rmi4_data->i2c_client = client;
rmi4_data->current_page = MASK_8BIT;
rmi4_data->board = platform_data;
rmi4_data->touch_stopped = false;
rmi4_data->sensor_sleep = false;
rmi4_data->irq_enabled = false;
rmi4_data->fw_updating = false;
rmi4_data->suspended = false;
rmi4_data->i2c_read = synaptics_rmi4_i2c_read;
rmi4_data->i2c_write = synaptics_rmi4_i2c_write;
rmi4_data->irq_enable = synaptics_rmi4_irq_enable;
rmi4_data->reset_device = synaptics_rmi4_reset_device;
rmi4_data->flip_x = rmi4_data->board->x_flip;
rmi4_data->flip_y = rmi4_data->board->y_flip;
if (rmi4_data->board->fw_image_name)
snprintf(rmi4_data->fw_image_name, NAME_BUFFER_SIZE, "%s",
rmi4_data->board->fw_image_name);
rmi4_data->input_dev->name = DRIVER_NAME;
rmi4_data->input_dev->phys = INPUT_PHYS_NAME;
rmi4_data->input_dev->id.bustype = BUS_I2C;
rmi4_data->input_dev->id.product = SYNAPTICS_DSX_DRIVER_PRODUCT;
rmi4_data->input_dev->id.version = SYNAPTICS_DSX_DRIVER_VERSION;
rmi4_data->input_dev->dev.parent = &client->dev;
input_set_drvdata(rmi4_data->input_dev, rmi4_data);
set_bit(EV_SYN, rmi4_data->input_dev->evbit);
set_bit(EV_KEY, rmi4_data->input_dev->evbit);
set_bit(EV_ABS, rmi4_data->input_dev->evbit);
set_bit(BTN_TOUCH, rmi4_data->input_dev->keybit);
set_bit(BTN_TOOL_FINGER, rmi4_data->input_dev->keybit);
#ifdef INPUT_PROP_DIRECT
set_bit(INPUT_PROP_DIRECT, rmi4_data->input_dev->propbit);
#endif
retval = synaptics_rmi4_regulator_configure(rmi4_data, true);
if (retval < 0) {
dev_err(&client->dev, "Failed to configure regulatorsn");
goto err_reg_configure;
}
retval = synaptics_rmi4_power_on(rmi4_data, true);
if (retval < 0) {
dev_err(&client->dev, "Failed to power onn");
goto err_power_device;
}
retval = synaptics_rmi4_pinctrl_init(rmi4_data);
if (!retval && rmi4_data->ts_pinctrl) {
/*
* Pinctrl handle is optional. If pinctrl handle is found
* let pins to be configured in active state. If not found
* continue further without error
*/
if (pinctrl_select_state(rmi4_data->ts_pinctrl,
rmi4_data->pinctrl_state_active))
dev_err(&rmi4_data->i2c_client->dev,
"Can not select %s pinstaten",
PINCTRL_STATE_ACTIVE);
}
retval = synaptics_rmi4_gpio_configure(rmi4_data, true);
if (retval < 0) {
dev_err(&client->dev, "Failed to configure gpiosn");
goto err_gpio_config;
}
init_waitqueue_head(&rmi4_data->wait);
mutex_init(&(rmi4_data->rmi4_io_ctrl_mutex));
INIT_LIST_HEAD(&rmi->support_fn_list);
mutex_init(&rmi->support_fn_list_mutex);
retval = synaptics_rmi4_query_device(rmi4_data);
if (retval < 0) {
dev_err(&client->dev,
"%s: Failed to query devicen",
__func__);
goto err_free_gpios;
}
if (platform_data->detect_device) {
retval = synaptics_rmi4_parse_dt_children(&client->dev,
platform_data, rmi4_data);
if (retval < 0)
dev_err(&client->dev,
"%s: Failed to parse device tree propertyn",
__func__);
}
if (rmi4_data->board->disp_maxx)
rmi4_data->disp_maxx = rmi4_data->board->disp_maxx;
else
rmi4_data->disp_maxx = rmi4_data->sensor_max_x;
if (rmi4_data->board->disp_maxy)
rmi4_data->disp_maxy = rmi4_data->board->disp_maxy;
else
rmi4_data->disp_maxy = rmi4_data->sensor_max_y;
if (rmi4_data->board->disp_minx)
rmi4_data->disp_minx = rmi4_data->board->disp_minx;
else
rmi4_data->disp_minx = 0;
if (rmi4_data->board->disp_miny)
rmi4_data->disp_miny = rmi4_data->board->disp_miny;
else
rmi4_data->disp_miny = 0;
input_set_abs_params(rmi4_data->input_dev,
ABS_MT_POSITION_X, rmi4_data->disp_minx,
rmi4_data->disp_maxx, 0, 0);
input_set_abs_params(rmi4_data->input_dev,
ABS_MT_POSITION_Y, rmi4_data->disp_miny,
rmi4_data->disp_maxy, 0, 0);
input_set_abs_params(rmi4_data->input_dev,
ABS_PRESSURE, 0, 255, 0, 0);
#ifdef REPORT_2D_W
input_set_abs_params(rmi4_data->input_dev,
ABS_MT_TOUCH_MAJOR, 0,
rmi4_data->max_touch_width, 0, 0);
input_set_abs_params(rmi4_data->input_dev,
ABS_MT_TOUCH_MINOR, 0,
rmi4_data->max_touch_width, 0, 0);
#endif
#ifdef TYPE_B_PROTOCOL
input_mt_init_slots(rmi4_data->input_dev,
rmi4_data->num_of_fingers, 0);
#endif
i2c_set_clientdata(client, rmi4_data);
f1a = NULL;
mutex_lock(&rmi->support_fn_list_mutex);
if (!list_empty(&rmi->support_fn_list)) {
list_for_each_entry(fhandler, &rmi->support_fn_list, link) {
if (fhandler->fn_number == SYNAPTICS_RMI4_F1A)
f1a = fhandler->data;
}
}
mutex_unlock(&rmi->support_fn_list_mutex);
if (f1a) {
for (ii = 0; ii < f1a->valid_button_count; ii++) {
set_bit(f1a->button_map[ii],
rmi4_data->input_dev->keybit);
input_set_capability(rmi4_data->input_dev,
EV_KEY, f1a->button_map[ii]);
}
}
retval = input_register_device(rmi4_data->input_dev);
if (retval) {
dev_err(&client->dev,
"%s: Failed to register input devicen",
__func__);
goto err_register_input;
}
configure_sleep(rmi4_data);
if (!exp_fn_inited) {
mutex_init(&exp_fn_list_mutex);
INIT_LIST_HEAD(&exp_fn_list);
exp_fn_inited = 1;
}
rmi4_data->det_workqueue =
create_singlethread_workqueue("rmi_det_workqueue");
INIT_DELAYED_WORK(&rmi4_data->det_work,
synaptics_rmi4_detection_work);
queue_delayed_work(rmi4_data->det_workqueue,
&rmi4_data->det_work,
msecs_to_jiffies(EXP_FN_DET_INTERVAL));
rmi4_data->irq = gpio_to_irq(platform_data->irq_gpio);
retval = request_threaded_irq(rmi4_data->irq, NULL,
synaptics_rmi4_irq, platform_data->irq_flags,
DRIVER_NAME, rmi4_data);
rmi4_data->irq_enabled = true;
if (retval < 0) {
dev_err(&client->dev,
"%s: Failed to create irq threadn",
__func__);
goto err_enable_irq;
}
rmi4_data->dir = debugfs_create_dir(DEBUGFS_DIR_NAME, NULL);
if (rmi4_data->dir == NULL || IS_ERR(rmi4_data->dir)) {
dev_err(&client->dev,
"%s: Failed to create debugfs directory, rc = %ldn",
__func__, PTR_ERR(rmi4_data->dir));
retval = PTR_ERR(rmi4_data->dir);
goto err_create_debugfs_dir;
}
temp = debugfs_create_file("suspend", S_IRUSR | S_IWUSR, rmi4_data->dir,
rmi4_data, &debug_suspend_fops);
if (temp == NULL || IS_ERR(temp)) {
dev_err(&client->dev,
"%s: Failed to create suspend debugfs file, rc = %ldn",
__func__, PTR_ERR(temp));
retval = PTR_ERR(temp);
goto err_create_debugfs_file;
}
for (attr_count = 0; attr_count < ARRAY_SIZE(attrs); attr_count++) {
retval = sysfs_create_file(&client->dev.kobj,
&attrs[attr_count].attr);
if (retval < 0) {
dev_err(&client->dev,
"%s: Failed to create sysfs attributesn",
__func__);
goto err_sysfs;
}
}
synaptics_rmi4_sensor_wake(rmi4_data);
retval = synaptics_rmi4_irq_enable(rmi4_data, true);
if (retval < 0) {
dev_err(&client->dev,
"%s: Failed to enable attention interruptn",
__func__);
goto err_sysfs;
}
synaptics_secure_touch_init(rmi4_data);
synaptics_secure_touch_stop(rmi4_data, 1);
retval = synaptics_rmi4_check_configuration(rmi4_data);
if (retval < 0) {
dev_err(&client->dev, "Failed to check configurationn");
return retval;
}
return retval;
err_sysfs:
for (attr_count--; attr_count >= 0; attr_count--) {
sysfs_remove_file(&rmi4_data->input_dev->dev.kobj,
&attrs[attr_count].attr);
}
err_create_debugfs_file:
debugfs_remove_recursive(rmi4_data->dir);
err_create_debugfs_dir:
free_irq(rmi4_data->irq, rmi4_data);
err_enable_irq:
cancel_delayed_work_sync(&rmi4_data->det_work);
flush_workqueue(rmi4_data->det_workqueue);
destroy_workqueue(rmi4_data->det_workqueue);
input_unregister_device(rmi4_data->input_dev);
err_register_input:
mutex_lock(&rmi->support_fn_list_mutex);
if (!list_empty(&rmi->support_fn_list)) {
list_for_each_entry_safe(fhandler, next_fhandler,
&rmi->support_fn_list, link) {
if (fhandler->fn_number == SYNAPTICS_RMI4_F1A)
synaptics_rmi4_f1a_kfree(fhandler);
else {
kfree(fhandler->data);
kfree(fhandler->extra);
}
kfree(fhandler);
}
}
mutex_unlock(&rmi->support_fn_list_mutex);
err_free_gpios:
if (gpio_is_valid(rmi4_data->board->reset_gpio))
gpio_free(rmi4_data->board->reset_gpio);
if (gpio_is_valid(rmi4_data->board->irq_gpio))
gpio_free(rmi4_data->board->irq_gpio);
err_gpio_config:
if (rmi4_data->ts_pinctrl) {
if (IS_ERR_OR_NULL(rmi4_data->pinctrl_state_release)) {
devm_pinctrl_put(rmi4_data->ts_pinctrl);
rmi4_data->ts_pinctrl = NULL;
} else {
retval = pinctrl_select_state(rmi4_data->ts_pinctrl,
rmi4_data->pinctrl_state_release);
if (retval)
pr_err("failed to select release pinctrl staten");
}
}
synaptics_rmi4_power_on(rmi4_data, false);
err_power_device:
synaptics_rmi4_regulator_configure(rmi4_data, false);
err_reg_configure:
input_free_device(rmi4_data->input_dev);
rmi4_data->input_dev = NULL;
err_input_device:
kfree(rmi4_data);
return retval;
}
在上述代码中，通过i2c_smbus_read_byte_data()函数对其寄存器信息进行读取即可完成其时间信息的获取，也可以通过i2c_transfer完成对其 寄存器的信息的批量读取。
