| /* |
| * 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/init.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); |