linux/drivers/i2c/busses/i2c-acorn.c
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  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

  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 #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00

97 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* ARM IOC/IOMD i2c driver.
*
* Copyright (C) 2000 Russell King
*
* 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,
.name = "ioc",
.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);
MODULE_AUTHOR("Russell King <linux@armlinux.org.uk>");
MODULE_DESCRIPTION("ARM IOC/IOMD i2c driver");
MODULE_LICENSE("GPL v2");