如何使得触摸按键驱动正常运行？
我的平台: Beagle Bone Black, Ubuntu, kernel: 3.14.29-ti-r46
触摸芯片: MPR121, connect to Beagle's i2c-2
我需要使触摸按键芯片MPR121 (Freescal) 工作在我的 Beagle Bone Black上. 内核驱动是现成的，但是它需要结合device tree才能工作。
我的做法：首先我创建一个设备树文件dts file 用于支持MPR121，如下:tomxue@ubuntu:~/Tom/Source_Code/BBB/Ubuntu/ti-linux-kernel-dev/KERNEL/arch/arm/boot/dts$ cat am335x-bone-i2c2-mpr121.dts
/*
* Copyright (C) 2012 Texas Instruments Incorporated -
*
* 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.
*/
/dts-v1/;
#include "am33xx.dtsi"
#include "am335x-bone-common.dtsi"
#include "am335x-bone-common-pinmux.dtsi"
/ {
model = "TI AM335x BeagleBone Black";
compatible = "ti,am335x-bone-black", "ti,am335x-bone", "ti,am33xx";
};
&ocp {
/* i2c2 */
P9_19_pinmux {
mode = "i2c";
};
P9_20_pinmux {
mode = "i2c";
};
};
&i2c2 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <>; /* pinctrl-0 = <&i2c2_pins>; */
clock-frequency = <100000>;
touchkey: mpr121@5a {
compatible = "fsl,mpr121";
reg = <0x5a>;
};
};
#include "am335x-bone-i2c2-cape-eeprom.dtsi"对应的Makefile(在dts目录内):dtb-$(CONFIG_ARCH_OMAP2PLUS) += omap2420-h4.dtb \
...
am335x-base0033.dtb \
am335x-bone-i2c2-mpr121.dtb \
am3517-craneboard.dtb \然后我就重新编译内核+设备树，使用BeagleBone提供的脚本烧写内核镜像，模块和设备树。
重启之后，先看看内核版本：root@arm:/dev/input# uname -a
Linux arm 3.14.29-ti-r46 #2 SMP PREEMPT Tue Apr 21 14:30:14 CST 2015 armv7l armv7l armv7l GNU/Linux加载相应的模块：root@arm:~# insmod mpr121_touchkey.ko可是dmesg中没有任何关于mpr121的信息。我又检查了一下i2c-2总线，mpr121已经连在上面了，地址是0x5a，和设备树中设置的一样：
root@arm:~# i2cdetect -y -r 2
0123456789abcdef
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- UU UU UU UU -- -- 5a -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --最后，我看了一下这个目录，按照内核模块源码显示，它应该在input目录下生成相应的设备文件，但是实际上找不到。root@arm:/dev/input# ls
mice这到底是怎么回事？我需要怎么做才能把该驱动模块正常跑起来？
谢谢！
补充下，内核模块文件为mpr121_touchkey.c ，在这里：drivers/input/keyboard，其源码如下：/*
* Touchkey driver for Freescale MPR121 Controllor
*
* Copyright (C) 2011 Freescale Semiconductor, Inc.
* Author: Zhang Jiejing <jiejing.zhang@freescale.com>
*
* Based on mcs_touchkey.c
*
* 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/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/i2c/mpr121_touchkey.h>
/* Register definitions */
#define ELE_TOUCH_STATUS_0_ADDR 0x0
#define ELE_TOUCH_STATUS_1_ADDR 0X1
#define MHD_RISING_ADDR 0x2b
#define NHD_RISING_ADDR 0x2c
#define NCL_RISING_ADDR 0x2d
#define FDL_RISING_ADDR 0x2e
#define MHD_FALLING_ADDR 0x2f
#define NHD_FALLING_ADDR 0x30
#define NCL_FALLING_ADDR 0x31
#define FDL_FALLING_ADDR 0x32
#define ELE0_TOUCH_THRESHOLD_ADDR 0x41
#define ELE0_RELEASE_THRESHOLD_ADDR 0x42
#define AFE_CONF_ADDR 0x5c
#define FILTER_CONF_ADDR 0x5d
/*
* ELECTRODE_CONF_ADDR: This register configures the number of
* enabled capacitance sensing inputs and its run/suspend mode.
*/
#define ELECTRODE_CONF_ADDR 0x5e
#define ELECTRODE_CONF_QUICK_CHARGE 0x80
#define AUTO_CONFIG_CTRL_ADDR 0x7b
#define AUTO_CONFIG_USL_ADDR 0x7d
#define AUTO_CONFIG_LSL_ADDR 0x7e
#define AUTO_CONFIG_TL_ADDR 0x7f
/* Threshold of touch/release trigger */
#define TOUCH_THRESHOLD 0x08
#define RELEASE_THRESHOLD 0x05
/* Masks for touch and release triggers */
#define TOUCH_STATUS_MASK 0xfff
/* MPR121 has 12 keys */
#define MPR121_MAX_KEY_COUNT 12
struct mpr121_touchkey {
struct i2c_client *client;
struct input_dev *input_dev;
unsigned int key_val;
unsigned int statusbits;
unsigned int keycount;
u16 keycodes;
};
struct mpr121_init_register {
int addr;
u8 val;
};
static const struct mpr121_init_register init_reg_table[] = {
{ MHD_RISING_ADDR, 0x1 },
{ NHD_RISING_ADDR, 0x1 },
{ MHD_FALLING_ADDR, 0x1 },
{ NHD_FALLING_ADDR, 0x1 },
{ NCL_FALLING_ADDR, 0xff },
{ FDL_FALLING_ADDR, 0x02 },
{ FILTER_CONF_ADDR, 0x04 },
{ AFE_CONF_ADDR, 0x0b },
{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
};
static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
{
struct mpr121_touchkey *mpr121 = dev_id;
struct i2c_client *client = mpr121->client;
struct input_dev *input = mpr121->input_dev;
unsigned int key_num, key_val, pressed;
int reg;
reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
if (reg < 0) {
dev_err(&client->dev, "i2c read error [%d]\n", reg);
goto out;
}
reg <<= 8;
reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
if (reg < 0) {
dev_err(&client->dev, "i2c read error [%d]\n", reg);
goto out;
}
reg &= TOUCH_STATUS_MASK;
/* use old press bit to figure out which bit changed */
key_num = ffs(reg ^ mpr121->statusbits) - 1;
pressed = reg & (1 << key_num);
mpr121->statusbits = reg;
key_val = mpr121->keycodes;
input_event(input, EV_MSC, MSC_SCAN, key_num);
input_report_key(input, key_val, pressed);
input_sync(input);
dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
pressed ? "pressed" : "released");
out:
return IRQ_HANDLED;
}
static int mpr121_phys_init(const struct mpr121_platform_data *pdata,
struct mpr121_touchkey *mpr121,
struct i2c_client *client)
{
const struct mpr121_init_register *reg;
unsigned char usl, lsl, tl, eleconf;
int i, t, vdd, ret;
/* Set up touch/release threshold for ele0-ele11 */
for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
if (ret < 0)
goto err_i2c_write;
ret = i2c_smbus_write_byte_data(client, t + 1,
RELEASE_THRESHOLD);
if (ret < 0)
goto err_i2c_write;
}
/* Set up init register */
for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
reg = &init_reg_table;
ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
if (ret < 0)
goto err_i2c_write;
}
/*
* Capacitance on sensing input varies and needs to be compensated.
* The internal MPR121-auto-configuration can do this if it's
* registers are set properly (based on pdata->vdd_uv).
*/
vdd = pdata->vdd_uv / 1000;
usl = ((vdd - 700) * 256) / vdd;
lsl = (usl * 65) / 100;
tl = (usl * 90) / 100;
ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
/*
* Quick charge bit will let the capacitive charge to ready
* state quickly, or the buttons may not function after system
* boot.
*/
eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
eleconf);
if (ret != 0)
goto err_i2c_write;
dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
return 0;
err_i2c_write:
dev_err(&client->dev, "i2c write error: %d\n", ret);
return ret;
}
static int mpr_touchkey_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
const struct mpr121_platform_data *pdata =
dev_get_platdata(&client->dev);
struct mpr121_touchkey *mpr121;
struct input_dev *input_dev;
int error;
int i;
if (!pdata) {
dev_err(&client->dev, "no platform data defined\n");
return -EINVAL;
}
if (!pdata->keymap || !pdata->keymap_size) {
dev_err(&client->dev, "missing keymap data\n");
return -EINVAL;
}
if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
dev_err(&client->dev, "too many keys defined\n");
return -EINVAL;
}
if (!client->irq) {
dev_err(&client->dev, "irq number should not be zero\n");
return -EINVAL;
}
mpr121 = kzalloc(sizeof(struct mpr121_touchkey), GFP_KERNEL);
input_dev = input_allocate_device();
if (!mpr121 || !input_dev) {
dev_err(&client->dev, "Failed to allocate memory\n");
error = -ENOMEM;
goto err_free_mem;
}
mpr121->client = client;
mpr121->input_dev = input_dev;
mpr121->keycount = pdata->keymap_size;
input_dev->name = "Freescale MPR121 Touchkey";
input_dev->id.bustype = BUS_I2C;
input_dev->dev.parent = &client->dev;
input_dev->evbit = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
input_dev->keycode = mpr121->keycodes;
input_dev->keycodesize = sizeof(mpr121->keycodes);
input_dev->keycodemax = mpr121->keycount;
for (i = 0; i < pdata->keymap_size; i++) {
input_set_capability(input_dev, EV_KEY, pdata->keymap);
mpr121->keycodes = pdata->keymap;
}
error = mpr121_phys_init(pdata, mpr121, client);
if (error) {
dev_err(&client->dev, "Failed to init register\n");
goto err_free_mem;
}
error = request_threaded_irq(client->irq, NULL,
mpr_touchkey_interrupt,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
client->dev.driver->name, mpr121);
if (error) {
dev_err(&client->dev, "Failed to register interrupt\n");
goto err_free_mem;
}
error = input_register_device(input_dev);
if (error)
goto err_free_irq;
i2c_set_clientdata(client, mpr121);
device_init_wakeup(&client->dev, pdata->wakeup);
return 0;
err_free_irq:
free_irq(client->irq, mpr121);
err_free_mem:
input_free_device(input_dev);
kfree(mpr121);
return error;
}
static int mpr_touchkey_remove(struct i2c_client *client)
{
struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
free_irq(client->irq, mpr121);
input_unregister_device(mpr121->input_dev);
kfree(mpr121);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mpr_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
if (device_may_wakeup(&client->dev))
enable_irq_wake(client->irq);
i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
return 0;
}
static int mpr_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
if (device_may_wakeup(&client->dev))
disable_irq_wake(client->irq);
i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
mpr121->keycount);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
static const struct i2c_device_id mpr121_id[] = {
{ "mpr121_touchkey", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mpr121_id);
static struct i2c_driver mpr_touchkey_driver = {
.driver = {
.name = "mpr121",
.owner = THIS_MODULE,
.pm = &mpr121_touchkey_pm_ops,
},
.id_table = mpr121_id,
.probe = mpr_touchkey_probe,
.remove = mpr_touchkey_remove,
};
module_i2c_driver(mpr_touchkey_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
本帖最后由 linuxfellow 于 2015-04-26 11:35 编辑
运行这个命令看看：
echo mpr121 0x5a > /sys/bus/i2c/devices/i2c-2/new_device
本帖最后由 tomxue0126 于 2015-04-26 17:47 编辑
回复 2# linuxfellow
多谢！
执行上述命令，然后就会多出一个目录，如下：i2c-2# echo mpr121 0x5a > /sys/bus/i2c/devices/i2c
root@arm:/sys/bus/i2c/devices/i2c-2# ls
2-00542-00562-005a device name power uevent
2-00552-0057delete_devicei2c-devnew_devicesubsystem
root@arm:/sys/bus/i2c/devices/i2c-2# cd 2-005a/
root@arm:/sys/bus/i2c/devices/i2c-2/2-005a# ls
modaliasnamepowersubsystemuevent
然后呢？里面貌似找不到有用的信息，我的硬件端触摸按键触发的话，也找不到对应的驱动输出
而/dev/input/目录下，还是只有一个mice文件
接下来应该做什么？
本帖最后由 linuxfellow 于 2015-04-27 05:28 编辑
/sys/bus/i2c/devices/i2c-2/2-005a 应该就是你的device
从i2c角度，你的设备和驱动都有
你的系统内核没有配置input event, 添加后应该出现/dev/input/event*
然后你可以运行一个evtest程序，你触摸屏幕时，相应的event就会打印在console里
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