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97 lines
1.9 KiB
97 lines
1.9 KiB
/* |
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* linux/drivers/acorn/char/i2c.c |
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* |
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* Copyright (C) 2000 Russell King |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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* |
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* ARM IOC/IOMD i2c driver. |
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* |
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* On Acorn machines, the following i2c devices are on the bus: |
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* - PCF8583 real time clock & static RAM |
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*/ |
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#include <linux/module.h> |
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#include <linux/i2c.h> |
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#include <linux/i2c-algo-bit.h> |
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#include <linux/io.h> |
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#include <mach/hardware.h> |
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#include <asm/hardware/ioc.h> |
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#define FORCE_ONES 0xdc |
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#define SCL 0x02 |
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#define SDA 0x01 |
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/* |
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* We must preserve all non-i2c output bits in IOC_CONTROL. |
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* Note also that we need to preserve the value of SCL and |
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* SDA outputs as well (which may be different from the |
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* values read back from IOC_CONTROL). |
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*/ |
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static u_int force_ones; |
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static void ioc_setscl(void *data, int state) |
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{ |
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u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); |
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u_int ones = force_ones; |
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if (state) |
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ones |= SCL; |
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else |
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ones &= ~SCL; |
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force_ones = ones; |
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ioc_writeb(ioc_control | ones, IOC_CONTROL); |
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} |
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static void ioc_setsda(void *data, int state) |
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{ |
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u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); |
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u_int ones = force_ones; |
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if (state) |
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ones |= SDA; |
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else |
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ones &= ~SDA; |
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force_ones = ones; |
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ioc_writeb(ioc_control | ones, IOC_CONTROL); |
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} |
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static int ioc_getscl(void *data) |
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{ |
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return (ioc_readb(IOC_CONTROL) & SCL) != 0; |
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} |
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static int ioc_getsda(void *data) |
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{ |
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return (ioc_readb(IOC_CONTROL) & SDA) != 0; |
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} |
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static struct i2c_algo_bit_data ioc_data = { |
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.setsda = ioc_setsda, |
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.setscl = ioc_setscl, |
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.getsda = ioc_getsda, |
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.getscl = ioc_getscl, |
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.udelay = 80, |
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.timeout = HZ, |
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}; |
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static struct i2c_adapter ioc_ops = { |
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.nr = 0, |
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.name = "ioc", |
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.algo_data = &ioc_data, |
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}; |
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static int __init i2c_ioc_init(void) |
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{ |
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force_ones = FORCE_ONES | SCL | SDA; |
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return i2c_bit_add_numbered_bus(&ioc_ops); |
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} |
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module_init(i2c_ioc_init);
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