/* * Basic I2C functions * * Copyright (c) 2004 Texas Instruments * * This package is free software; you can redistribute it and/or * modify it under the terms of the license found in the file * named COPYING that should have accompanied this file. * * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * Author: Jian Zhang jzhang@ti.com, Texas Instruments * * Copyright (c) 2003 Wolfgang Denk, wd@denx.de * Rewritten to fit into the current U-Boot framework * * Adapted for OMAP2420 I2C, r-woodruff2@ti.com * */ #include <common.h> #ifdef CONFIG_DRIVER_OMAP24XX_I2C #include <asm/arch/i2c.h> #include <asm/io.h> #define inw(a) __raw_readw(a) #define outw(a,v) __raw_writew(a,v) static void wait_for_bb (void); static u16 wait_for_pin (void); static void flush_fifo(void); void i2c_init (int speed, int slaveadd) { u16 scl; outw(0x2, I2C_SYSC); /* for ES2 after soft reset */ udelay(1000); outw(0x0, I2C_SYSC); /* will probably self clear but */ if (inw (I2C_CON) & I2C_CON_EN) { outw (0, I2C_CON); udelay (50000); } /* 12Mhz I2C module clock */ outw (0, I2C_PSC); speed = speed/1000; /* 100 or 400 */ scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */ outw (scl, I2C_SCLL); outw (scl, I2C_SCLH); /* own address */ outw (slaveadd, I2C_OA); outw (I2C_CON_EN, I2C_CON); /* have to enable intrrupts or OMAP i2c module doesn't work */ outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE); udelay (1000); flush_fifo(); outw (0xFFFF, I2C_STAT); outw (0, I2C_CNT); } static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) { int i2c_error = 0; u16 status; /* wait until bus not busy */ wait_for_bb (); /* one byte only */ outw (1, I2C_CNT); /* set slave address */ outw (devaddr, I2C_SA); /* no stop bit needed here */ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON); status = wait_for_pin (); if (status & I2C_STAT_XRDY) { /* Important: have to use byte access */ *(volatile u8 *) (I2C_DATA) = regoffset; udelay (20000); if (inw (I2C_STAT) & I2C_STAT_NACK) { i2c_error = 1; } } else { i2c_error = 1; } if (!i2c_error) { /* free bus, otherwise we can't use a combined transction */ outw (0, I2C_CON); while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) { udelay (10000); /* Have to clear pending interrupt to clear I2C_STAT */ outw (0xFFFF, I2C_STAT); } wait_for_bb (); /* set slave address */ outw (devaddr, I2C_SA); /* read one byte from slave */ outw (1, I2C_CNT); /* need stop bit here */ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON); status = wait_for_pin (); if (status & I2C_STAT_RRDY) { *value = inw (I2C_DATA); udelay (20000); } else { i2c_error = 1; } if (!i2c_error) { outw (I2C_CON_EN, I2C_CON); while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) { udelay (10000); outw (0xFFFF, I2C_STAT); } } } flush_fifo(); outw (0xFFFF, I2C_STAT); outw (0, I2C_CNT); return i2c_error; } static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value) { int i2c_error = 0; u16 status, stat; /* wait until bus not busy */ wait_for_bb (); /* two bytes */ outw (2, I2C_CNT); /* set slave address */ outw (devaddr, I2C_SA); /* stop bit needed here */ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX | I2C_CON_STP, I2C_CON); /* wait until state change */ status = wait_for_pin (); if (status & I2C_STAT_XRDY) { /* send out two bytes */ outw ((value << 8) + regoffset, I2C_DATA); /* must have enough delay to allow BB bit to go low */ udelay (50000); if (inw (I2C_STAT) & I2C_STAT_NACK) { i2c_error = 1; } } else { i2c_error = 1; } if (!i2c_error) { int eout = 200; outw (I2C_CON_EN, I2C_CON); while ((stat = inw (I2C_STAT)) || (inw (I2C_CON) & I2C_CON_MST)) { udelay (1000); /* have to read to clear intrrupt */ outw (0xFFFF, I2C_STAT); if(--eout == 0) /* better leave with error than hang */ break; } } flush_fifo(); outw (0xFFFF, I2C_STAT); outw (0, I2C_CNT); return i2c_error; } static void flush_fifo(void) { u16 stat; /* note: if you try and read data when its not there or ready * you get a bus error */ while(1){ stat = inw(I2C_STAT); if(stat == I2C_STAT_RRDY){ inw(I2C_DATA); outw(I2C_STAT_RRDY,I2C_STAT); udelay(1000); }else break; } } int i2c_probe (uchar chip) { int res = 1; /* default = fail */ if (chip == inw (I2C_OA)) { return res; } /* wait until bus not busy */ wait_for_bb (); /* try to read one byte */ outw (1, I2C_CNT); /* set slave address */ outw (chip, I2C_SA); /* stop bit needed here */ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON); /* enough delay for the NACK bit set */ udelay (50000); if (!(inw (I2C_STAT) & I2C_STAT_NACK)) { res = 0; /* success case */ flush_fifo(); outw(0xFFFF, I2C_STAT); } else { outw(0xFFFF, I2C_STAT); /* failue, clear sources*/ outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); /* finish up xfer */ udelay(20000); wait_for_bb (); } flush_fifo(); outw (0, I2C_CNT); /* don't allow any more data in...we don't want it.*/ outw(0xFFFF, I2C_STAT); return res; } int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len) { int i; if (alen > 1) { printf ("I2C read: addr len %d not supported\n", alen); return 1; } if (addr + len > 256) { printf ("I2C read: address out of range\n"); return 1; } for (i = 0; i < len; i++) { if (i2c_read_byte (chip, addr + i, &buffer[i])) { printf ("I2C read: I/O error\n"); i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE); return 1; } } return 0; } int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len) { int i; if (alen > 1) { printf ("I2C read: addr len %d not supported\n", alen); return 1; } if (addr + len > 256) { printf ("I2C read: address out of range\n"); return 1; } for (i = 0; i < len; i++) { if (i2c_write_byte (chip, addr + i, buffer[i])) { printf ("I2C read: I/O error\n"); i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE); return 1; } } return 0; } static void wait_for_bb (void) { int timeout = 10; u16 stat; outw(0xFFFF, I2C_STAT); /* clear current interruts...*/ while ((stat = inw (I2C_STAT) & I2C_STAT_BB) && timeout--) { outw (stat, I2C_STAT); udelay (50000); } if (timeout <= 0) { printf ("timed out in wait_for_bb: I2C_STAT=%x\n", inw (I2C_STAT)); } outw(0xFFFF, I2C_STAT); /* clear delayed stuff*/ } static u16 wait_for_pin (void) { u16 status; int timeout = 10; do { udelay (1000); status = inw (I2C_STAT); } while ( !(status & (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY | I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK | I2C_STAT_AL)) && timeout--); if (timeout <= 0) { printf ("timed out in wait_for_pin: I2C_STAT=%x\n", inw (I2C_STAT)); outw(0xFFFF, I2C_STAT); } return status; } #endif /* CONFIG_DRIVER_OMAP24XX_I2C */