/*
* ADS7846 based touchscreen and sensor driver
*
* Copyright (c) 2005 David Brownell
* Copyright (c) 2006 Nokia Corporation
* Various changes: Imre Deak <imre.deak@nokia.com>
*
* Using code from:
* - corgi_ts.c
* Copyright (C) 2004-2005 Richard Purdie
* - omap_ts.[hc], ads7846.h, ts_osk.c
* Copyright (C) 2002 MontaVista Software
* Copyright (C) 2004 Texas Instruments
* Copyright (C) 2005 Dirk Behme
*
* 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/types.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/ads7846.h>
#include <linux/regulator/consumer.h>
#include <linux/module.h>
#include <asm/irq.h>
/*
* This code has been heavily tested on a Nokia 770, and lightly
* tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
* TSC2046 is just newer ads7846 silicon.
* Support for ads7843 tested on Atmel at91sam926x-EK.
* Support for ads7845 has only been stubbed in.
* Support for Analog Devices AD7873 and AD7843 tested.
*
* IRQ handling needs a workaround because of a shortcoming in handling
* edge triggered IRQs on some platforms like the OMAP1/2. These
* platforms don't handle the ARM lazy IRQ disabling properly, thus we
* have to maintain our own SW IRQ disabled status. This should be
* removed as soon as the affected platform's IRQ handling is fixed.
*
* App note sbaa036 talks in more detail about accurate sampling...
* that ought to help in situations like LCDs inducing noise (which
* can also be helped by using synch signals) and more generally.
* This driver tries to utilize the measures described in the app
* note. The strength of filtering can be set in the board-* specific
* files.
*/
#define TS_POLL_DELAY 1 /* ms delay before the first sample */
#define TS_POLL_PERIOD 5 /* ms delay between samples */
/* this driver doesn't aim at the peak continuous sample rate */
#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
struct ts_event {
/*
* For portability, we can't read 12 bit values using SPI (which
* would make the controller deliver them as native byte order u16
* with msbs zeroed). Instead, we read them as two 8-bit values,
* *** WHICH NEED BYTESWAPPING *** and range adjustment.
*/
u16 x;
u16 y;
u16 z1, z2;
bool ignore;
u8 x_buf[3];
u8 y_buf[3];
};
/*
* We allocate this separately to avoid cache line sharing issues when
* driver is used with DMA-based SPI controllers (like atmel_spi) on
* systems where main memory is not DMA-coherent (most non-x86 boards).
