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

/*
 * drivers/i2c/busses/i2c-ibm_iic.c
 *
 * Support for the IIC peripheral on IBM PPC 4xx
 *
 * Copyright (c) 2003, 2004 Zultys Technologies.
 * Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
 *
 * Copyright (c) 2008 PIKA Technologies
 * Sean MacLennan <smaclennan@pikatech.com>
 *
 * Based on original work by
 * 	Ian DaSilva  <idasilva@mvista.com>
 *      Armin Kuster <akuster@mvista.com>
 * 	Matt Porter  <mporter@mvista.com>
 *
 *      Copyright 2000-2003 MontaVista Software Inc.
 *
 * Original driver version was highly leveraged from i2c-elektor.c
 *
 *   	Copyright 1995-97 Simon G. Vogl
 *                1998-99 Hans Berglund
 *
 *   	With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
 *	and even Frodo Looijaard <frodol@dds.nl>
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>

#ifdef CONFIG_IBM_OCP
#include <asm/ocp.h>
#include <asm/ibm4xx.h>
#else
#include <linux/of_platform.h>
#endif

#include "i2c-ibm_iic.h"

#define DRIVER_VERSION "2.2"

MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
MODULE_LICENSE("GPL");

static int iic_force_poll;
module_param(iic_force_poll, bool, 0);
MODULE_PARM_DESC(iic_force_poll, "Force polling mode");

static int iic_force_fast;
module_param(iic_force_fast, bool, 0);
MODULE_PARM_DESC(iic_force_fast, "Force fast mode (400 kHz)");

#define DBG_LEVEL 0

#ifdef DBG
#undef DBG
#endif

#ifdef DBG2
#undef DBG2
#endif

#if DBG_LEVEL > 0
#  define DBG(f,x...)	printk(KERN_DEBUG "ibm-iic" f, ##x)
#else
#  define DBG(f,x...)	((void)0)
#endif
#if DBG_LEVEL > 1
#  define DBG2(f,x...) 	DBG(f, ##x)
#else
#  define DBG2(f,x...) 	((void)0)
#endif
#if DBG_LEVEL > 2
static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
{
	volatile struct iic_regs __iomem *iic = dev->vaddr;
	printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header);
	printk(KERN_DEBUG "  cntl     = 0x%02x, mdcntl = 0x%02x\n"
	       KERN_DEBUG "  sts      = 0x%02x, extsts = 0x%02x\n"
	       KERN_DEBUG "  clkdiv   = 0x%02x, xfrcnt = 0x%02x\n"
	       KERN_DEBUG "  xtcntlss = 0x%02x, directcntl = 0x%02x\n",
		in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts),
		in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt),
		in_8(&iic->xtcntlss), in_8(&iic->directcntl));
}
#  define DUMP_REGS(h,dev)	dump_iic_regs((h),(dev))
#else
#  define DUMP_REGS(h,dev)	((void)0)
#endif

/* Bus timings (in ns) for bit-banging */
static struct i2c_timings {
	unsigned int hd_sta;
	unsigned int su_sto;
	unsigned int low;
	unsigned int high;
	unsigned int buf;
} timings [] = {
/* Standard mode (100 KHz) */
{
	.hd_sta	= 4000,
	.su_sto	= 4000,
	.low	= 4700,
	.high	= 4000,
	.buf	= 4700,
},
/* Fast mode (400 KHz) */
{
	.hd_sta = 600,
	.su_sto	= 600,
	.low 	= 1300,
	.high 	= 600,
	.buf	= 1300,
}};

/* Enable/disable interrupt generation */
static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable)
{
	out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0);
}

/*
 * Initialize IIC interface.
 */
static void iic_dev_init(struct ibm_iic_private* dev)
{
	volatile struct iic_regs __iomem *iic = dev->vaddr;

	DBG("%d: init\n", dev->idx);

	/* Clear master address */
	out_8(&iic->lmadr, 0);
	out_8(&iic->hmadr, 0);

	/* Clear slave address */
	out_8(&iic->lsadr, 0);
	out_8(&iic->hsadr, 0);

	/* Clear status & extended status */
	out_8(&iic->sts, STS_SCMP | STS_IRQA);
	out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA
			    | EXTSTS_ICT | EXTSTS_XFRA);

	/* Set clock divider */
	out_8(&iic->clkdiv, dev->clckdiv);

	/* Clear transfer count */
	out_8(&iic->xfrcnt, 0);

	/* Clear extended control and status */
	out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC
			    | XTCNTLSS_SWS);

	/* Clear control register */
	out_8(&iic->cntl, 0);

	/* Enable interrupts if possible */
	iic_interrupt_mode(dev, dev->irq >= 0);

	/* Set mode control */
	out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS
			    | (dev->fast_mode ? MDCNTL_FSM : 0));

	DUMP_REGS(