/*
 *  Touchscreen driver for Sharp Corgi models (SL-C7xx)
 *
 *  Copyright (c) 2004-2005 Richard Purdie
 *
 *  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/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/irq.h>

#include <asm/arch/corgi.h>
#include <asm/arch/hardware.h>
#include <asm/arch/pxa-regs.h>


#define PWR_MODE_ACTIVE		0
#define PWR_MODE_SUSPEND	1

#define X_AXIS_MAX		3830
#define X_AXIS_MIN		150
#define Y_AXIS_MAX		3830
#define Y_AXIS_MIN		190
#define PRESSURE_MIN		0
#define PRESSURE_MAX		15000

struct ts_event {
	short pressure;
	short x;
	short y;
};

struct corgi_ts {
	char phys[32];
	struct input_dev input;
	struct timer_list timer;
	struct ts_event tc;
	int pendown;
	int power_mode;
};

#define STATUS_HSYNC		(GPLR(CORGI_GPIO_HSYNC) & GPIO_bit(CORGI_GPIO_HSYNC))

#define SyncHS()	while((STATUS_HSYNC) == 0); while((STATUS_HSYNC) != 0);
#define CCNT(a)		asm volatile ("mrc p14, 0, %0, C1, C0, 0" : "=r"(a))
#define CCNT_ON()	{int pmnc = 1; asm volatile ("mcr p14, 0, %0, C0, C0, 0" : : "r"(pmnc));}
#define CCNT_OFF()	{int pmnc = 0; asm volatile ("mcr p14, 0, %0, C0, C0, 0" : : "r"(pmnc));}

#define WAIT_HS_400_VGA		7013U	// 17.615us
#define WAIT_HS_400_QVGA	16622U	// 41.750us


/* ADS7846 Touch Screen Controller bit definitions */
#define ADSCTRL_PD0		(1u << 0)	/* PD0 */
#define ADSCTRL_PD1		(1u << 1)	/* PD1 */
#define ADSCTRL_DFR		(1u << 2)	/* SER/DFR */
#define ADSCTRL_MOD		(1u << 3)	/* Mode */
#define ADSCTRL_ADR_SH	4	/* Address setting */
#define ADSCTRL_STS		(1u << 7)	/* Start Bit */

/* External Functions */
extern int w100fb_get_xres(void);
extern int w100fb_get_blanking(void);
extern int w100fb_get_fastsysclk(void);
extern unsigned int get_clk_frequency_khz(int info);

static unsigned long calc_waittime(void)
{
	int w100fb_xres = w100fb_get_xres();
	unsigned int waittime = 0;

	if (w100fb_xres == 480 || w100fb_xres == 640) {
		waittime = WAIT_HS_400_VGA * get_clk_frequency_khz(0) / 398131U;

		if (w100fb_get_fastsysclk() == 100)
			waittime = waittime * 75 / 100;

		if (w100fb_xres == 640)
			waittime *= 3;

		return waittime;
	}

	return WAIT_HS_400_QVGA * get_clk_frequency_khz(0) / 398131U;
}

static int sync_receive_data_send_cmd(int doRecive, int doSend, unsigned int address, unsigned long wait_time)
{
	int pos = 0;
	unsigned long timer1 = 0, timer2;
	int dosleep;

	dosleep = !w100fb_get_blanking();

	if (dosleep && doSend) {
		CCNT_ON();
		/* polling HSync */
		SyncHS();
		/* get CCNT */
		CCNT(timer1);
	}

	if (doRecive)
		pos = corgi_ssp_ads7846_get();

	if (doSend) {
		int cmd = ADSCTRL_PD0 | ADSCTRL_PD1 | (address << ADSCTRL_ADR_SH) | ADSCTRL_STS;
		/* dummy command */
		corgi_ssp_ads7846_put(cmd);
		corgi_ssp_ads7846_get();

		if (dosleep) {
			/* Wait after HSync */
			CCNT(timer2);
			if (timer2-timer1 > wait_time) {
				/* timeout */
				SyncHS();
				/* get OSCR */
				CCNT(timer1);
				/* Wait after HSync */
				CCNT(timer2);
			}
			while (timer2 - timer1 < wait_time)
				CCNT(timer2);
		}
		corgi_ssp_ads7846_put(cmd);
		if (dosleep)
			CCNT_OFF();
	}
	return pos;
}

static int read_xydata(struct corgi_ts *corgi_ts)
{
	unsigned int x, y, z1, z2;
	unsigned long flags, wait_time;

	/* critical section */
	local_irq_save(flags);
	corgi_ssp_ads7846_lock();
	wait_time=calc_waittime();

	/* Y-axis */
	sync_receive_data_send_cmd(0, 1, 1u, wait_time);

	/* Y-axis */
	sync_receive_data_send_cmd(1, 1, 1u, wait_time);

	/* X-axis */
	y = sync_receive_data_send_cmd(1, 1, 5u, wait_time);

	/* Z1 */
	x = sync_receive_data_send_cmd(1, 1, 3u, wait_time);

	/* Z2 */
	z1 = sync_receive_data_send_cmd(1, 1, 4u, wait_time);
	z2 = sync_receive_data_send_cmd(1, 0, 4u, wait_time);

	/* Power-Down Enable */
	corgi_ssp_ads7846_put((1u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	corgi_ssp_ads7846_get();

	corgi_ssp_ads7846_unlock();
	local_irq_restore(flags);

	if (x== 0 || y == 0 || z1 == 0 || (x * (z2 - z1) / z1) >= 15000) {
		corgi_ts->tc.pressure = 0;
		return 0;
	}

	corgi_ts->tc.x = x;
	corgi_ts->tc.y = y;
	corgi_ts->tc.pressure = (x * (z2 - z1)) / z1;
	return 1;
}

static void new_data(struct corgi_ts *corgi_ts, struct pt_regs *regs)
{
	if (corgi_ts->power_mode != PWR_MODE_ACTIVE)
		return;

	if (!corgi_ts->tc.pressure && corgi_ts->pendown == 0)
		return;

	if (regs)
		input_regs(&corgi_ts->input, regs);

	input_report_abs(&corgi_ts->input, ABS_X, corgi_ts->tc.x);
	input_report_abs(&corgi_ts->input, ABS_Y, corgi_ts->tc.y);
	input_report_abs(&corgi_ts->input, ABS_PRESSURE, corgi_ts->tc.pressure);
	input_report_key(&corgi_ts->input, BTN_TOUCH, (corgi_ts->pendown != 0));
	input_sync(&corgi_ts->input);
}

static void ts_interrupt_main(struct corgi_ts *corgi_ts, int isTimer, struct pt_regs *regs)
{
	if ((GPLR(CORGI_GPIO_TP_INT) & GPIO_bit(CORGI_GPIO_TP_INT)) == 0) {
		/* Disable Interrupt */
		set_irq_type(CORGI_IRQ_GPIO_TP_INT, IRQT_NOEDGE);
		if (read_xydata(corgi_ts)) {
			corgi_ts->pendown = 1;
			new_data(corgi_ts, regs);
		}
		mod_timer(&corgi_ts->timer, jiffies + HZ / 100);
	} else {
		if (corgi_ts->pendown == 1 || corgi_ts->pendown == 2) {
			mod_timer(&corgi_ts->timer, jiffies + HZ / 100);
			corgi_ts->pendown++;
			return;
		}

		if (corgi_ts->pendown) {
			corgi_ts->tc.pressure = 0;
			new_data(corgi_ts, regs);
		}

		/* Enable Falling Edge */
		set_irq_type(CORGI_IRQ_GPIO_TP_INT, IRQT_FALLING);
		corgi_ts->pendown = 0;
	}
}

static void corgi_ts_timer(unsigned long data)
{
	struct corgi_ts *corgits_data = (struct corgi_ts *) data;
	ts_interrupt_main(corgits_data, 1, NULL);
}

static irqreturn_t ts_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	struct corgi_ts *corgits_data = dev_id;
	ts_interrupt_main(corgits_data, 0, regs);
	return IRQ_HANDLED;
}

#ifdef CONFIG_PM
static int corgits_suspend(struct device *dev, uint32_t state, uint32_t level)
{
	if (level == SUSPEND_POWER_DOWN) {
		struct corgi_ts *corgi_ts = dev_get_drvdata(dev);

		if (corgi_ts->pendown) {
			del_timer_sync(&corgi_ts->timer);
			corgi_ts->tc.pressure = 0;
			new_data(corgi_ts, NULL);
			corgi_ts->pendown = 0;
		}
		corgi_ts->power_mode = PWR_MODE_SUSPEND;

		corgi_ssp_ads7846_putget((1u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	}
	return 0;
}

static int corgits_resume(struct device *dev, uint32_t level)
{
	if (level == RESUME_POWER_ON) {
		struct corgi_ts *corgi_ts = dev_get_drvdata(dev);

		corgi_ssp_ads7846_putget((4u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
		/* Enable Falling Edge */
		set_irq_type(CORGI_IRQ_GPIO_TP_INT, IRQT_FALLING);
		corgi_ts->power_mode = PWR_MODE_ACTIVE;
	}
	return 0;
}
#else
#define corgits_suspend		NULL
#define corgits_resume		NULL
#endif

static int __init corgits_probe(struct device *dev)
{
	struct corgi_ts *corgi_ts;

	if (!(corgi_ts = kmalloc(sizeof(struct corgi_ts), GFP_KERNEL)))
		return -ENOMEM;

	dev_set_drvdata(dev, corgi_ts);

	memset(corgi_ts, 0, sizeof(struct corgi_ts));

	init_input_dev(&corgi_ts->input);
	corgi_ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
	corgi_ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
	input_set_abs_params(&corgi_ts->input, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
	input_set_abs_params(&corgi_ts->input, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
	input_set_abs_params(&corgi_ts->input, ABS_PRESSURE, PRESSURE_MIN, PRESSURE_MAX, 0, 0);

	strcpy(corgi_ts->phys, "corgits/input0");

	corgi_ts->input.private = corgi_ts;
	corgi_ts->input.name = "Corgi Touchscreen";
	corgi_ts->input.dev = dev;
	corgi_ts->input.phys = corgi_ts->phys;
	corgi_ts->input.id.bustype = BUS_HOST;
	corgi_ts->input.id.vendor = 0x0001;
	corgi_ts->input.id.product = 0x0002;
	corgi_ts->input.id.version = 0x0100;

	pxa_gpio_mode(CORGI_GPIO_TP_INT | GPIO_IN);
	pxa_gpio_mode(CORGI_GPIO_HSYNC | GPIO_IN);

	/* Initiaize ADS7846 Difference Reference mode */
	corgi_ssp_ads7846_putget((1u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	mdelay(5);
	corgi_ssp_ads7846_putget((3u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	mdelay(5);
	corgi_ssp_ads7846_putget((4u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	mdelay(5);
	corgi_ssp_ads7846_putget((5u << ADSCTRL_ADR_SH) | ADSCTRL_STS);
	mdelay(5);

	init_timer(&corgi_ts->timer);
	corgi_ts->timer.data = (unsigned long) corgi_ts;
	corgi_ts->timer.function = corgi_ts_timer;

	input_register_device(&corgi_ts->input);
	corgi_ts->power_mode = PWR_MODE_ACTIVE;

	if (request_irq(CORGI_IRQ_GPIO_TP_INT, ts_interrupt, SA_INTERRUPT, "ts", corgi_ts)) {
		input_unregister_device(&corgi_ts->input);
		kfree(corgi_ts);
		return -EBUSY;
	}

	/* Enable Falling Edge */
	set_irq_type(CORGI_IRQ_GPIO_TP_INT, IRQT_FALLING);

	printk(KERN_INFO "input: Corgi Touchscreen Registered\n");

	return 0;
}

static int corgits_remove(struct device *dev)
{
	struct corgi_ts *corgi_ts = dev_get_drvdata(dev);

	free_irq(CORGI_IRQ_GPIO_TP_INT, NULL);
	del_timer_sync(&corgi_ts->timer);
	input_unregister_device(&corgi_ts->input);
	kfree(corgi_ts);
	return 0;
}

static struct device_driver corgits_driver = {
	.name		= "corgi-ts",
	.bus		= &platform_bus_type,
	.probe		= corgits_probe,
	.remove		= corgits_remove,
	.suspend	= corgits_suspend,
	.resume		= corgits_resume,
};

static int __devinit corgits_init(void)
{
	return driver_register(&corgits_driver);
}

static void __exit corgits_exit(void)
{
	driver_unregister(&corgits_driver);
}

module_init(corgits_init);
module_exit(corgits_exit);

MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
MODULE_DESCRIPTION("Corgi TouchScreen Driver");
MODULE_LICENSE("GPL");