/* * (C) Copyright 2000 * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it * * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com> * Marius Groeger <mgroeger@sysgo.de> * * (C) Copyright 2003 Pengutronix e.K. * Robert Schwebel <r.schwebel@pengutronix.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 * * Back ported to the 8xx platform (from the 8260 platform) by * Murray.Jensen@cmst.csiro.au, 27-Jan-01. */ /* FIXME: this file is PXA255 specific! What about other XScales? */ #include <common.h> #ifdef CONFIG_HARD_I2C /* * - CFG_I2C_SPEED * - I2C_PXA_SLAVE_ADDR */ #include <asm/arch/hardware.h> #include <asm/arch/pxa-regs.h> #include <i2c.h> /*#define DEBUG_I2C 1 /###* activate local debugging output */ #define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */ #define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE) #define I2C_ISR_INIT 0x7FF #ifdef DEBUG_I2C #define PRINTD(x) printf x #else #define PRINTD(x) #endif /* Shall the current transfer have a start/stop condition? */ #define I2C_COND_NORMAL 0 #define I2C_COND_START 1 #define I2C_COND_STOP 2 /* Shall the current transfer be ack/nacked or being waited for it? */ #define I2C_ACKNAK_WAITACK 1 #define I2C_ACKNAK_SENDACK 2 #define I2C_ACKNAK_SENDNAK 4 /* Specify who shall transfer the data (master or slave) */ #define I2C_READ 0 #define I2C_WRITE 1 /* All transfers are described by this data structure */ struct i2c_msg { u8 condition; u8 acknack; u8 direction; u8 data; }; /** * i2c_pxa_reset: - reset the host controller * */ static void i2c_reset( void ) { ICR &= ~ICR_IUE; /* disable unit */ ICR |= ICR_UR; /* reset the unit */ udelay(100); ICR &= ~ICR_IUE; /* disable unit */ CKEN |= CKEN14_I2C; /* set the global I2C clock on */ ISAR = I2C_PXA_SLAVE_ADDR; /* set our slave address */ ICR = I2C_ICR_INIT; /* set control register values */ ISR = I2C_ISR_INIT; /* set clear interrupt bits */ ICR |= ICR_IUE; /* enable unit */ udelay(100); } /** * i2c_isr_set_cleared: - wait until certain bits of the I2C status register * are set and cleared * * @return: 0 in case of success, 1 means timeout (no match within 10 ms). */ static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask ) { int timeout = 10000; while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){ udelay( 10 ); if( timeout-- < 0 ) return 0; } return 1; } /** * i2c_transfer: - Transfer one byte over the i2c bus * * This function can tranfer a byte over the i2c bus in both directions. * It is used by the public API functions. * * @return: 0: transfer successful * -1: message is empty * -2: transmit timeout * -3: ACK missing * -4: receive timeout * -5: illegal parameters * -6: bus is busy and couldn't be aquired */ int i2c_transfer(struct i2c_msg *msg) { int ret; if (!msg) goto transfer_error_msg_empty; switch(msg->direction) { case I2C_WRITE: /* check if bus is not busy */ if (!i2c_isr_set_cleared(0,ISR_IBB)) goto transfer_error_bus_busy; /* start transmission */ ICR &= ~ICR_START; ICR &= ~ICR_STOP; IDBR = msg->data; if (msg->condition == I2C_COND_START) ICR |= ICR_START; if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP; if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK; if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK; ICR &= ~ICR_ALDIE; ICR |= ICR_TB; /* transmit register empty? */ if (!i2c_isr_set_cleared(ISR_ITE,0)) goto transfer_error_transmit_timeout; /* clear 'transmit empty' state */ ISR |= ISR_ITE; /* wait for ACK from slave */ if (msg->acknack == I2C_ACKNAK_WAITACK) if (!i2c_isr_set_cleared(0,ISR_ACKNAK)) goto transfer_error_ack_missing; break; case I2C_READ: /* check if bus is not busy */ if (!i2c_isr_set_cleared(0,ISR_IBB)) goto transfer_error_bus_busy; /* start receive */ ICR &= ~ICR_START; ICR &= ~ICR_STOP; if (msg->condition == I2C_COND_START) ICR |= ICR_START; if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP; if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK; if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK; ICR &= ~ICR_ALDIE; ICR |= ICR_TB; /* receive register full? */ if (!i2c_isr_set_cleared(ISR_IRF,0)) goto transfer_error_receive_timeout; msg->data = IDBR; /* clear 'receive empty' state */ ISR |= ISR_IRF; break; default: goto transfer_error_illegal_param; } return 0; transfer_error_msg_empty: PRINTD(("i2c_transfer: error: 'msg' is empty\n")); ret = -1; goto i2c_transfer_finish; transfer_error_transmit_timeout: PRINTD(("i2c_transfer: error: transmit timeout\n")); ret = -2; goto i2c_transfer_finish; transfer_error_ack_missing: PRINTD(("i2c_transfer: error: ACK missing\n")); ret = -3; goto i2c_transfer_finish; transfer_error_receive_timeout: PRINTD(("i2c_transfer: error: receive timeout\n")); ret = -4; goto i2c_transfer_finish; transfer_error_illegal_param: PRINTD(("i2c_transfer: error: illegal parameters\n")); ret = -5; goto i2c_transfer_finish; transfer_error_bus_busy: PRINTD(("i2c_transfer: error: bus is busy\n")); ret = -6; goto i2c_transfer_finish; i2c_transfer_finish: PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR)); i2c_reset(); return ret; } /* ------------------------------------------------------------------------ */ /* API Functions */ /* ------------------------------------------------------------------------ */ void i2c_init(int speed, int slaveaddr) { #ifdef CFG_I2C_INIT_BOARD /* call board specific i2c bus reset routine before accessing the */ /* environment, which might be in a chip on that bus. For details */ /* about this problem see doc/I2C_Edge_Conditions. */ i2c_init_board(); #endif } /** * i2c_probe: - Test if a chip answers for a given i2c address * * @chip: address of the chip which is searched for * @return: 0 if a chip was found, -1 otherwhise */ int i2c_probe(uchar chip) { struct i2c_msg msg; i2c_reset(); msg.condition = I2C_COND_START; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = (chip << 1) + 1; if (i2c_transfer(&msg)) return -1; msg.condition = I2C_COND_STOP; msg.acknack = I2C_ACKNAK_SENDNAK; msg.direction = I2C_READ; msg.data = 0x00; if (i2c_transfer(&msg)) return -1; return 0; } /** * i2c_read: - Read multiple bytes from an i2c device * * The higher level routines take into account that this function is only * called with len < page length of the device (see configuration file) * * @chip: address of the chip which is to be read * @addr: i2c data address within the chip * @alen: length of the i2c data address (1..2 bytes) * @buffer: where to write the data * @len: how much byte do we want to read * @return: 0 in case of success */ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) { struct i2c_msg msg; u8 addr_bytes[3]; /* lowest...highest byte of data address */ int ret; PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len)); i2c_reset(); /* dummy chip address write */ PRINTD(("i2c_read: dummy chip address write\n")); msg.condition = I2C_COND_START; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = (chip << 1); msg.data &= 0xFE; if ((ret=i2c_transfer(&msg))) return -1; /* * send memory address bytes; * alen defines how much bytes we have to send. */ /*addr &= ((1 << CFG_EEPROM_PAGE_WRITE_BITS)-1); */ addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF); addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF); addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF); while (--alen >= 0) { PRINTD(("i2c_read: send memory word address byte %1d\n",alen)); msg.condition = I2C_COND_NORMAL; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = addr_bytes[alen]; if ((ret=i2c_transfer(&msg))) return -1; } /* start read sequence */ PRINTD(("i2c_read: start read sequence\n")); msg.condition = I2C_COND_START; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = (chip << 1); msg.data |= 0x01; if ((ret=i2c_transfer(&msg))) return -1; /* read bytes; send NACK at last byte */ while (len--) { if (len==0) { msg.condition = I2C_COND_STOP; msg.acknack = I2C_ACKNAK_SENDNAK; } else { msg.condition = I2C_COND_NORMAL; msg.acknack = I2C_ACKNAK_SENDACK; } msg.direction = I2C_READ; msg.data = 0x00; if ((ret=i2c_transfer(&msg))) return -1; *(buffer++) = msg.data; PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer)); } i2c_reset(); return 0; } /** * i2c_write: - Write multiple bytes to an i2c device * * The higher level routines take into account that this function is only * called with len < page length of the device (see configuration file) * * @chip: address of the chip which is to be written * @addr: i2c data address within the chip * @alen: length of the i2c data address (1..2 bytes) * @buffer: where to find the data to be written * @len: how much byte do we want to read * @return: 0 in case of success */ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) { struct i2c_msg msg; u8 addr_bytes[3]; /* lowest...highest byte of data address */ PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len)); i2c_reset(); /* chip address write */ PRINTD(("i2c_write: chip address write\n")); msg.condition = I2C_COND_START; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = (chip << 1); msg.data &= 0xFE; if (i2c_transfer(&msg)) return -1; /* * send memory address bytes; * alen defines how much bytes we have to send. */ addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF); addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF); addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF); while (--alen >= 0) { PRINTD(("i2c_write: send memory word address\n")); msg.condition = I2C_COND_NORMAL; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = addr_bytes[alen]; if (i2c_transfer(&msg)) return -1; } /* write bytes; send NACK at last byte */ while (len--) { PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer)); if (len==0) msg.condition = I2C_COND_STOP; else msg.condition = I2C_COND_NORMAL; msg.acknack = I2C_ACKNAK_WAITACK; msg.direction = I2C_WRITE; msg.data = *(buffer++); if (i2c_transfer(&msg)) return -1; } i2c_reset(); return 0; } uchar i2c_reg_read (uchar chip, uchar reg) { char buf; PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg)); i2c_read(chip, reg, 1, &buf, 1); return (buf); } void i2c_reg_write(uchar chip, uchar reg, uchar val) { PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val)); i2c_write(chip, reg, 1, &val, 1); } #endif /* CONFIG_HARD_I2C */