[mirror_ubuntu-bionic-kernel.git] / drivers / i2c / busses / i2c-acorn.c

/*
 *  linux/drivers/acorn/char/i2c.c
 *
 *  Copyright (C) 2000 Russell King
 *
 * 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.
 *
 *  ARM IOC/IOMD i2c driver.
 *
 *  On Acorn machines, the following i2c devices are on the bus:
 *	- PCF8583 real time clock & static RAM
 */
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/hardware/ioc.h>

#define FORCE_ONES	0xdc
#define SCL		0x02
#define SDA		0x01

/*
 * We must preserve all non-i2c output bits in IOC_CONTROL.
 * Note also that we need to preserve the value of SCL and
 * SDA outputs as well (which may be different from the
 * values read back from IOC_CONTROL).
 */
static u_int force_ones;

static void ioc_setscl(void *data, int state)
{
	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
	u_int ones = force_ones;

	if (state)
		ones |= SCL;
	else
		ones &= ~SCL;

	force_ones = ones;

 	ioc_writeb(ioc_control | ones, IOC_CONTROL);
}

static void ioc_setsda(void *data, int state)
{
	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
	u_int ones = force_ones;

	if (state)
		ones |= SDA;
	else
		ones &= ~SDA;

	force_ones = ones;

 	ioc_writeb(ioc_control | ones, IOC_CONTROL);
}

static int ioc_getscl(void *data)
{
	return (ioc_readb(IOC_CONTROL) & SCL) != 0;
}

static int ioc_getsda(void *data)
{
	return (ioc_readb(IOC_CONTROL) & SDA) != 0;
}

static struct i2c_algo_bit_data ioc_data = {
	.setsda		= ioc_setsda,
	.setscl		= ioc_setscl,
	.getsda		= ioc_getsda,
	.getscl		= ioc_getscl,
	.udelay		= 80,
	.timeout	= HZ,
};

static struct i2c_adapter ioc_ops = {
	.nr			= 0,
	.algo_data		= &ioc_data,
};

static int __init i2c_ioc_init(void)
{
	force_ones = FORCE_ONES | SCL | SDA;

	return i2c_bit_add_numbered_bus(&ioc_ops);
}

module_init(i2c_ioc_init);
Commit	Line	Data
8d91cbad RK	1	/*
	2	* linux/drivers/acorn/char/i2c.c
	3	*
	4	* Copyright (C) 2000 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* ARM IOC/IOMD i2c driver.
	11	*
	12	* On Acorn machines, the following i2c devices are on the bus:
	13	* - PCF8583 real time clock & static RAM
	14	*/
66769330	15	#include <linux/module.h>
8d91cbad RK	16	#include <linux/i2c.h>
8d91cbad RK	17	#include <linux/i2c-algo-bit.h>
99730225	18	#include <linux/io.h>
8d91cbad	19
a09e64fb	20	#include <mach/hardware.h>
8d91cbad	21	#include <asm/hardware/ioc.h>
8d91cbad RK	22
	23	#define FORCE_ONES 0xdc
	24	#define SCL 0x02
	25	#define SDA 0x01
	26
	27	/*
	28	* We must preserve all non-i2c output bits in IOC_CONTROL.
	29	* Note also that we need to preserve the value of SCL and
	30	* SDA outputs as well (which may be different from the
	31	* values read back from IOC_CONTROL).
	32	*/
	33	static u_int force_ones;
	34
	35	static void ioc_setscl(void *data, int state)
	36	{
	37	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL \| SDA);
	38	u_int ones = force_ones;
	39
	40	if (state)
	41	ones \|= SCL;
	42	else
	43	ones &= ~SCL;
	44
	45	force_ones = ones;
	46
	47	ioc_writeb(ioc_control \| ones, IOC_CONTROL);
	48	}
	49
	50	static void ioc_setsda(void *data, int state)
	51	{
	52	u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL \| SDA);
	53	u_int ones = force_ones;
	54
	55	if (state)
	56	ones \|= SDA;
	57	else
	58	ones &= ~SDA;
	59
	60	force_ones = ones;
	61
	62	ioc_writeb(ioc_control \| ones, IOC_CONTROL);
	63	}
	64
	65	static int ioc_getscl(void *data)
	66	{
	67	return (ioc_readb(IOC_CONTROL) & SCL) != 0;
	68	}
	69
	70	static int ioc_getsda(void *data)
	71	{
	72	return (ioc_readb(IOC_CONTROL) & SDA) != 0;
	73	}
	74
	75	static struct i2c_algo_bit_data ioc_data = {
	76	.setsda = ioc_setsda,
	77	.setscl = ioc_setscl,
	78	.getsda = ioc_getsda,
	79	.getscl = ioc_getscl,
	80	.udelay = 80,
082a4cf8	81	.timeout = HZ,
8d91cbad RK	82	};
	83
	84	static struct i2c_adapter ioc_ops = {
531660ef	85	.nr = 0,
8d91cbad RK	86	.algo_data = &ioc_data,
	87	};
	88
	89	static int __init i2c_ioc_init(void)
	90	{
	91	force_ones = FORCE_ONES \| SCL \| SDA;
	92
531660ef	93	return i2c_bit_add_numbered_bus(&ioc_ops);
8d91cbad RK	94	}
8d91cbad RK	95
2a9915c8	96	module_init(i2c_ioc_init);