path: root/drivers/i2c/busses/i2c-pxa.c

/*
 *  i2c_adap_pxa.c
 *
 *  I2C adapter for the PXA I2C bus access.
 *
 *  Copyright (C) 2002 Intrinsyc Software Inc.
 *  Copyright (C) 2004-2005 Deep Blue Solutions Ltd.
 *
 *  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.
 *
 *  History:
 *    Apr 2002: Initial version [CS]
 *    Jun 2002: Properly separated algo/adap [FB]
 *    Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem]
 *    Jan 2003: added limited signal handling [Kai-Uwe Bloem]
 *    Sep 2004: Major rework to ensure efficient bus handling [RMK]
 *    Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood]
 *    Feb 2005: Rework slave mode handling [RMK]
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/i2c-pxa.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>

#include <asm/irq.h>
#include <asm/io.h>
#include <plat/i2c.h>

/*
 * I2C register offsets will be shifted 0 or 1 bit left, depending on
 * different SoCs
 */
#define REG_SHIFT_0	(0 << 0)
#define REG_SHIFT_1	(1 << 0)
#define REG_SHIFT(d)	((d) & 0x1)

static const struct platform_device_id i2c_pxa_id_table[] = {
	{ "pxa2xx-i2c",		REG_SHIFT_1 },
	{ "pxa3xx-pwri2c",	REG_SHIFT_0 },
	{ },
};
MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);

/*
 * I2C registers and bit definitions
 */
#define IBMR		(0x00)
#define IDBR		(0x08)
#define ICR		(0x10)
#define ISR		(0x18)
#define ISAR		(0x20)

#define ICR_START	(1 << 0)	   /* start bit */
#define ICR_STOP	(1 << 1)	   /* stop bit */
#define ICR_ACKNAK	(1 << 2)	   /* send ACK(0) or NAK(1) */
#define ICR_TB		(1 << 3)	   /* transfer byte bit */
#define ICR_MA		(1 << 4)	   /* master abort */
#define ICR_SCLE	(1 << 5)	   /* master clock enable */
#define ICR_IUE		(1 << 6)	   /* unit enable */
#define ICR_GCD		(1 << 7)	   /* general call disable */
#define ICR_ITEIE	(1 << 8)	   /* enable tx interrupts */
#define ICR_IRFIE	(1 << 9)	   /* enable rx interrupts */
#define ICR_BEIE	(1 << 10)	   /* enable bus error ints */
#define ICR_SSDIE	(1 << 11)	   /* slave STOP detected int enable */
#define ICR_ALDIE	(1 << 12)	   /* enable arbitration interrupt */
#define ICR_SADIE	(1 << 13)	   /* slave address detected int enable */
#define ICR_UR		(1 << 14)	   /* unit reset */
#define ICR_FM		(1 << 15)	   /* fast mode */

#define ISR_RWM		(1 << 0)	   /* read/write mode */
#define ISR_ACKNAK	(1 << 1)	   /* ack/nak status */
#define ISR_UB		(1 << 2)	   /* unit busy */
#define ISR_IBB		(1 << 3)	   /* bus busy */
#define ISR_SSD		(1 << 4)	   /* slave stop detected */
#define ISR_ALD		(1 << 5)	   /* arbitration loss detected */
#define ISR_ITE		(1 << 6)	   /* tx buffer empty */
#define ISR_IRF		(1 << 7)	   /* rx buffer full */
#define ISR_GCAD	(1 << 8)	   /* general call address detected */
#define ISR_SAD		(1 << 9)	   /* slave address detected */
#define ISR_BED		(1 << 10)	   /* bus error no ACK/NAK */

struct pxa_i2c {
	spinlock_t		lock;
	wait_queue_head_t	wait;
	struct i2c_msg		*msg;
	unsigned int		msg_num;
	unsigned int		msg_idx;
	unsigned int		msg_ptr;
	unsigned int		slave_addr;

	struct i2c_adapter	adap;
	struct clk		*clk;
#ifdef CONFIG_I2C_PXA_SLAVE
	struct i2c_slave_client *slave;
#endif

	unsigned int		irqlogidx;
	u32			isrlog[32];
	u32			icrlog[32];

	void __iomem		*reg_base;
	unsigned int		reg_shift;

	unsigned long		iobase;
	unsigned long		iosize;

	int			irq;
	unsigned int		use_pio :1;
	unsigned int		fast_mode :1;
};

#define _IBMR(i2c)	((i2c)->reg_base + (0x0 << (i2c)->reg_shift))
#define _IDBR(i2c)	((i2c)->reg_base + (0x4 << (i2c)->reg_shift))
#define _ICR(i2c)	((i2c)->reg_base + (0x8 << (i2c)->reg_shift))
#define _ISR(i2c)	((i2c)->reg_base + (0xc << (i2c)->reg_shift))
#define _ISAR(i2c)	((i2c)->reg_base + (0x10 << (i2c)->reg_shift))

/*
 * I2C Slave mode address
 */
#define I2C_PXA_SLAVE_ADDR      0x1

#ifdef DEBUG

struct bits {
	u32	mask;
	const char *set;
	const char *unset;
};
#define PXA_BIT(m, s, u)	{ .mask = m, .set = s, .unset = u }

static inline void
decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
{
	printk("%s %08x: ", prefix, val);
	while (num--) {
		const char *str = val & bits->mask ? bits->set : bits->unset;
		if (str)
			printk("%s "