linux 触摸屏 驱动

触摸屏驱动，挂在平台驱动下，input 子系统中。

/* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Copyright (c) 2004 Arnaud Patard <[e-mail]> * iPAQ H1940 touchscreen support * * ChangeLog * * 2004-09-05: Herbert P枚tzl <[e-mail]> *- added clock (de-)allocation code * * 2005-03-06: Arnaud Patard <[e-mail]> *      - h1940_ -> s3c2410 (this driver is now also used on the n30 *        machines :P) *      - Debug messages are now enabled with the config option *        TOUCHSCREEN_S3C2410_DEBUG *      - Changed the way the value are read *      - Input subsystem should now work *      - Use ioremap and readl/writel * */  #include <linux/autoconf.h>#include <linux/errno.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/input.h>#include <linux/init.h>#include <linux/serio.h>#include <linux/delay.h>#include <asm/io.h>#include <asm/irq.h>#include <linux/platform_device.h>#include <asm/arch/regs-adc.h>#include <asm/arch/regs-gpio.h>#include <asm/arch/ts.h>#include <asm/hardware/clock.h>/* For ts.dev.id.version */#define S3C2410TSVERSION0x0101#define WAIT4INT(x)  (((x)<<8) | \     S3C2410_ADCTSC_YM_SEN | S3C2410_ADCTSC_YP_SEN | S3C2410_ADCTSC_XP_SEN | \     S3C2410_ADCTSC_XY_PST(3))#define AUTOPST     (S3C2410_ADCTSC_YM_SEN | S3C2410_ADCTSC_YP_SEN | S3C2410_ADCTSC_XP_SEN | \     S3C2410_ADCTSC_AUTO_PST | S3C2410_ADCTSC_XY_PST(0))#define DEBUG_LVL    KERN_DEBUGMODULE_AUTHOR("Arnaud Patard <[e-mail]>");MODULE_DESCRIPTION("s3c2440 touchscreen driver");MODULE_LICENSE("GPL");/* * Definitions & global arrays. */static char *s3c2410ts_name = "s3c2440 TouchScreen";/* * Per-touchscreen data. */struct s3c2410ts {struct input_dev *dev;long xp;long yp;int count;int shift;char phys[32];};static struct s3c2410ts ts;static void __iomem *base_addr;static inline void s3c2410_ts_connect(void){s3c2410_gpio_cfgpin(S3C2410_GPG12, S3C2410_GPG12_XMON);s3c2410_gpio_cfgpin(S3C2410_GPG13, S3C2410_GPG13_nXPON);s3c2410_gpio_cfgpin(S3C2410_GPG14, S3C2410_GPG14_YMON);s3c2410_gpio_cfgpin(S3C2410_GPG15, S3C2410_GPG15_nYPON);}static void touch_timer_fire(unsigned long data){  unsigned long data0;  unsigned long data1;int updown;int tmp;//add by lili 2006-12-12  data0 = readl(base_addr+S3C2410_ADCDAT0);  data1 = readl(base_addr+S3C2410_ADCDAT1); updown = (!(data0 & S3C2410_ADCDAT0_UPDOWN)) && (!(data1 & S3C2410_ADCDAT0_UPDOWN)); if (updown) { if (ts.count != 0) { ts.xp >>= ts.shift; ts.yp >>= ts.shift;//reset coordinate system add by lili 2006-12-12#ifdef CONFIG_RESET_COORDINATE_SYSTEMtmp = ts.xp;ts.xp = ts.yp;ts.yp = tmp;#endif#ifdef CONFIG_TOUCHSCREEN_S3C2410_DEBUG { struct timeval tv; do_gettimeofday(&tv);printk("Touch screen info:");//add by lili 2006-12-9 printk(DEBUG_LVL "T: %06d, X: %03ld, Y: %03ld\n", (int)tv.tv_usec, ts.xp, ts.yp); }#endif input_report_abs(ts.dev, ABS_X, ts.xp); input_report_abs(ts.dev, ABS_Y, ts.yp); input_report_key(ts.dev, BTN_TOUCH, 1); input_report_abs(ts.dev, ABS_PRESSURE, 1); input_sync(ts.dev); } ts.xp = 0; ts.yp = 0; ts.count = 0; writel(S3C2410_ADCTSC_PULL_UP_DISABLE | AUTOPST, base_addr+S3C2410_ADCTSC); writel(readl(base_addr+S3C2410_ADCCON) | S3C2410_ADCCON_ENABLE_START, base_addr+S3C2410_ADCCON); } else { ts.count = 0; input_report_key(ts.dev, BTN_TOUCH, 0); input_report_abs(ts.dev, ABS_PRESSURE, 0); input_sync(ts.dev); writel(WAIT4INT(0), base_addr+S3C2410_ADCTSC); }}static struct timer_list touch_timer =TIMER_INITIALIZER(touch_timer_fire, 0, 0);static irqreturn_t stylus_updown(int irq, void *dev_id, struct pt_regs *regs){unsigned long data0;unsigned long data1;int updown;disable_irq(IRQ_TC);//add by lili 2007-6-19data0 = readl(base_addr+S3C2410_ADCDAT0);data1 = readl(base_addr+S3C2410_ADCDAT1);updown = (!(data0 & S3C2410_ADCDAT0_UPDOWN)) && (!(data1 & S3C2410_ADCDAT0_UPDOWN));/* TODO we should never get an interrupt with updown set while * the timer is running, but maybe we ought to verify that the * timer isn't running anyways. */if (updown)touch_timer_fire(0);enable_irq(IRQ_TC);//add by lili 2007-6-19return IRQ_HANDLED;}static irqreturn_t stylus_action(int irq, void *dev_id, struct pt_regs *regs){unsigned long data0;unsigned long data1;disable_irq(IRQ_ADC);//add by lili  2007-06-19data0 = readl(base_addr+S3C2410_ADCDAT0);data1 = readl(base_addr+S3C2410_ADCDAT1);ts.xp += data0 & S3C2410_ADCDAT0_XPDATA_MASK;ts.yp += data1 & S3C2410_ADCDAT1_YPDATA_MASK;ts.count++;        if (ts.count < (1<<ts.shift)) {writel(S3C2410_ADCTSC_PULL_UP_DISABLE | AUTOPST, base_addr+S3C2410_ADCTSC);writel(readl(base_addr+S3C2410_ADCCON) | S3C2410_ADCCON_ENABLE_START, base_addr+S3C2410_ADCCON);} else {mod_timer(&touch_timer, jiffies+1);writel(WAIT4INT(1), base_addr+S3C2410_ADCTSC);}enable_irq(IRQ_ADC);//add by lili 2007-6-19return IRQ_HANDLED;}static struct clk*adc_clock;/* * The functions for inserting/removing us as a module. */static int __init s3c2410ts_probe(struct device *dev){struct s3c2410_ts_mach_info *info;info = ( struct s3c2410_ts_mach_info *)dev->platform_data;if (!info){printk(KERN_ERR "Hm... too bad : no platform data for ts\n");return -EINVAL;}#ifdef CONFIG_TOUCHSCREEN_S3C2410_DEBUGprintk(DEBUG_LVL "Entering s3c2410ts_init\n");#endifadc_clock = clk_get(NULL, "adc");if (!adc_clock) {printk(KERN_ERR "failed to get adc clock source\n");return -ENOENT;}//clk_use(adc_clock);clk_enable(adc_clock);#ifdef CONFIG_TOUCHSCREEN_S3C2410_DEBUGprintk(DEBUG_LVL "got and enabled clock\n");#endifbase_addr=ioremap(S3C2410_PA_ADC,0x20);if (base_addr == NULL) {printk(KERN_ERR "Failed to remap register block\n");return -ENOMEM;}/* Configure GPIOs */s3c2410_ts_connect();if ((info->presc&0xff) > 0)writel(S3C2410_ADCCON_PRSCEN | S3C2410_ADCCON_PRSCVL(info->presc&0xFF),\     base_addr+S3C2410_ADCCON);elsewritel(0,base_addr+S3C2410_ADCCON);/* Initialise registers */if ((info->delay&0xffff) > 0)writel(info->delay & 0xffff,  base_addr+S3C2410_ADCDLY);writel(WAIT4INT(0), base_addr+S3C2410_ADCTSC);/* Initialise input stuff */memset(&ts, 0, sizeof(struct s3c2410ts));//init_input_dev(&ts.dev);ts.dev = input_allocate_device();ts.dev->evbit[0] = BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);ts.dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT(BTN_TOUCH);input_set_abs_params(ts.dev, ABS_X, 0, 0x3FF, 0, 0);input_set_abs_params(ts.dev, ABS_Y, 0, 0x3FF, 0, 0);input_set_abs_params(ts.dev, ABS_PRESSURE, 0, 1, 0, 0);sprintf(ts.phys, "ts0");ts.dev->private = &ts;ts.dev->name = s3c2410ts_name;ts.dev->phys = ts.phys;ts.dev->id.bustype = BUS_RS232;ts.dev->id.vendor = 0xDEAD;ts.dev->id.product = 0xBEEF;ts.dev->id.version = S3C2410TSVERSION;ts.shift = info->oversampling_shift;/* Get irqs */if (request_irq(IRQ_ADC, stylus_action, SA_SAMPLE_RANDOM,"s3c2410_action", ts.dev)) {printk(KERN_ERR "s3c2410_ts.c: Could not allocate ts IRQ_ADC !\n");iounmap(base_addr);return -EIO;}if (request_irq(IRQ_TC, stylus_updown, SA_SAMPLE_RANDOM,"s3c2410_action", ts.dev)) {printk(KERN_ERR "s3c2410_ts.c: Could not allocate ts IRQ_TC !\n");iounmap(base_addr);return -EIO;}/* *for debug regs */#ifdef CONFIG_TOUCHSCREEN_S3C2410_DEBUGunsigned long debug_regs;debug_regs = 0;debug_regs = readl(base_addr+S3C2410_ADCCON);printk("S3C2410_ADCCON:0x%08lx\n",debug_regs);debug_regs = readl(base_addr+S3C2410_ADCTSC);printk("S3C2410_ADCTSC:0x%08lx\n",debug_regs);debug_regs = readl(base_addr+S3C2410_ADCDLY);printk("S3C2410_ADCDLY:0x%08lx\n",debug_regs);#endifprintk(KERN_INFO "%s successfully loaded\n", s3c2410ts_name);/* All went ok, so register to the input system */input_register_device(ts.dev);return 0;}static int s3c2410ts_remove(struct device *dev){disable_irq(IRQ_ADC);disable_irq(IRQ_TC);free_irq(IRQ_TC,ts.dev);free_irq(IRQ_ADC,ts.dev);if (adc_clock) {clk_disable(adc_clock);//clk_unuse(adc_clock);clk_put(adc_clock);adc_clock = NULL;}input_unregister_device(ts.dev);iounmap(base_addr);return 0;}static struct device_driver s3c2410ts_driver = {       .name           = "s3c2410-ts",       .bus            = &platform_bus_type,       .probe          = s3c2410ts_probe,       .remove         = s3c2410ts_remove,};int __init s3c2410ts_init(void){return driver_register(&s3c2410ts_driver);}void __exit s3c2410ts_exit(void){driver_unregister(&s3c2410ts_driver);}module_init(s3c2410ts_init);module_exit(s3c2410ts_exit);/*    Local variables:        compile-command: "make ARCH=arm CROSS_COMPILE=/usr/local/arm/3.3.2/bin/arm-linux- -k -C ../../.."        c-basic-offset: 8    End:*/

分析一下这个驱动。

1.数据结构分析。

    触摸屏设备：1.继承输入子系统设备；2.坐标位置；3.ADC采集次数；4.采样移位；5设备名称。

    定时器

    device_driver

    platform_device

     s3c2410_ts_mach_info：触摸屏的配置信息

2.驱动分析

a.入口，出口。module_init(s3c2410ts_init);module_exit(s3c2410ts_exit);

      入口和出口只做了一件事：将device_driver结构向系统中注册和注销。

    在device_driver 中关联了设备，总线，以及相关操作(个人理解为驱动操作)。
 b.关于平台总线设备驱动

    1.在平台资源中通过s3c24xx_ts_set_platdata(&utu2440_ts_cfg);将触摸屏的配置信息加到平台资源中去，其中utu2440_ts_cfg为配置的平台资源，在探测函数中，通过传入 的平台设备，利用dev->platform_data取出数据。

    2.探测函数主要做的事情

       1.取出平台设备中关于触摸屏的配置信息

       2.取出adc 采样的时钟，并使能时钟

       3.映射ADC的物理地址

       4.配置2440的引脚，使之工作在触摸屏模式

       5.根据配置信息，配置相关的寄存器

      6.为触摸屏设备分配内存，初始化输入子系统，并向输入子系统模型设备中填充相应内容

      7.请求中断，包括ADC中断和TS中断

      8.输入子系统注册

   3.移除函数主要做的事情

      1.禁止中断，释放中断

       2.禁止时钟，释放时钟

       3. 在输入子系统中注销

       4.取消地址映射

c.中断响应

   1.ADC中断响应:stylus_action

    2.触摸屏的中断响应:stylus_updown

d.触摸屏的事件报告:touch_timer_fire