/* * (C) Copyright 2002 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. * * See file CREDITS for list of people who contributed to this * project. * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <config.h> #include <common.h> #include <asm/io.h> #include "hardware.h" #include "i2c.h" static void i2c_start (void); static void i2c_stop (void); static int i2c_write (u8 data); static void i2c_read (u8 * data); static inline void i2c_port_start (void); static inline void i2c_clock (unsigned int val); static inline void i2c_data (unsigned int val); static inline unsigned int i2c_in (void); static inline void i2c_write_bit (unsigned int val); static inline unsigned int i2c_read_bit (void); static inline void i2c_udelay (unsigned int time); int i2c_read_byte ( u8 * data, u8 dev, u8 offset) { int err = 0; i2c_start(); err = ! i2c_write(dev); if (! err) { err = ! i2c_write(offset); } if (! err) { i2c_start(); } if (! err) { err = ! i2c_write(dev | 0x01); } if (! err) { i2c_read(data); } i2c_stop(); return ! err; } static inline void i2c_udelay ( unsigned int time) { int v; asm volatile("mtdec %0" : : "r" (time * ((CFG_BUS_CLK / 4) / 1000000))); do { asm volatile("isync; mfdec %0" : "=r" (v)); } while (v >= 0); } /* Low-level hardware access */ #define BIT_GPDATA 0x80000000 #define BIT_GPCLK 0x40000000 static inline void i2c_port_start (void) { out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~(BIT_GPCLK | BIT_GPDATA)); out32(REG(CPC0, GPOUT), in32(REG(CPC0, GPOUT)) & ~(BIT_GPCLK | BIT_GPDATA)); iobarrier_rw(); i2c_udelay(1); } static inline void i2c_clock ( unsigned int val) { if (val) { out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPCLK); } else { out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPCLK); } iobarrier_rw(); i2c_udelay(1); } static inline void i2c_data ( unsigned int val) { if (val) { out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPDATA); } else { out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPDATA); } iobarrier_rw(); i2c_udelay(1); } static inline unsigned int i2c_in (void) { unsigned int val = ((in32(REG(CPC0, GPIN)) & BIT_GPDATA) != 0)?1:0; iobarrier_rw(); return val; } /* Protocol implementation */ static inline void i2c_write_bit ( unsigned int val) { i2c_data(val); i2c_udelay(10); i2c_clock(1); i2c_udelay(10); i2c_clock(0); i2c_udelay(10); } static inline unsigned int i2c_read_bit (void) { unsigned int val; i2c_data(1); i2c_udelay(10); i2c_clock(1); i2c_udelay(10); val = i2c_in(); i2c_clock(0); i2c_udelay(10); return val; } unsigned int i2c_reset (void) { unsigned int val; int i; i2c_port_start(); i=0; do { i2c_udelay(10); i2c_clock(0); i2c_udelay(10); i2c_clock(1); i2c_udelay(10); val = i2c_in(); i++; } while ((i<9)&&(val==0)); return (val); } static void i2c_start (void) { i2c_data(1); i2c_clock(1); i2c_udelay(10); i2c_data(0); i2c_udelay(10); i2c_clock(0); i2c_udelay(10); } static void i2c_stop (void) { i2c_data(0); i2c_udelay(10); i2c_clock(1); i2c_udelay(10); i2c_data(1); i2c_udelay(10); } static int i2c_write ( u8 data) { unsigned int i; for (i = 0; i < 8; i++) { i2c_write_bit(data >> 7); data <<= 1; } return i2c_read_bit() == 0; } static void i2c_read ( u8 * data) { unsigned int i; u8 val = 0; for (i = 0; i < 8; i++) { val <<= 1; val |= i2c_read_bit(); } *data = val; i2c_write_bit(1); /* NoAck */ }