/* * (C) Copyright 2002 * David Mueller, ELSOFT AG, d.mueller@elsoft.ch * * 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 */ /* This code should work for both the S3C2400 and the S3C2410 * as they seem to have the same I2C controller inside. * The different address mapping is handled by the s3c24xx.h files below. */ #include #ifdef CONFIG_DRIVER_S3C24X0_I2C #if defined(CONFIG_S3C2400) #include #elif defined(CONFIG_S3C2410) #include #endif #include #ifdef CONFIG_HARD_I2C #define IIC_WRITE 0 #define IIC_READ 1 #define IIC_OK 0 #define IIC_NOK 1 #define IIC_NACK 2 #define IIC_NOK_LA 3 /* Lost arbitration */ #define IIC_NOK_TOUT 4 /* time out */ #define IICSTAT_BSY 0x20 /* Busy bit */ #define IICSTAT_NACK 0x01 /* Nack bit */ #define IICCON_IRPND 0x10 /* Interrupt pending bit */ #define IIC_MODE_MT 0xC0 /* Master Transmit Mode */ #define IIC_MODE_MR 0x80 /* Master Receive Mode */ #define IIC_START_STOP 0x20 /* START / STOP */ #define IIC_TXRX_ENA 0x10 /* I2C Tx/Rx enable */ #define IIC_TIMEOUT 1 /* 1 seconde */ static int GetIICSDA(void) { return (rGPEDAT & 0x8000) >> 15; } static void SetIICSDA(int x) { rGPEDAT = (rGPEDAT & ~0x8000) | (x&1) << 15; } static void SetIICSCL(int x) { rGPEDAT = (rGPEDAT & ~0x4000) | (x&1) << 14; } static int WaitForXfer(void) { int i, status; i = IIC_TIMEOUT * 1000; status = rIICCON; while ((i > 0) && !(status & IICCON_IRPND)) { udelay(1000); status = rIICCON; i--; } return(status & IICCON_IRPND) ? IIC_OK : IIC_NOK_TOUT; } static int IsACK(void) { return(!(rIICSTAT & IICSTAT_NACK)); } static void ReadWriteByte(void) { rIICCON &= ~IICCON_IRPND; } void i2c_init (int speed, int slaveadd) { ulong freq, pres = 16, div; int i, status; /* wait for some time to give previous transfer a chance to finish */ i = IIC_TIMEOUT * 1000; status = rIICSTAT; while ((i > 0) && (status & IICSTAT_BSY)) { udelay(1000); status = rIICSTAT; i--; } if ((status & IICSTAT_BSY) || GetIICSDA() == 0) { ulong old_gpecon = rGPECON; /* bus still busy probably by (most) previously interrupted transfer */ /* set IICSDA and IICSCL (GPE15, GPE14) to GPIO */ rGPECON = (rGPECON & ~0xF0000000) | 0x10000000; /* toggle IICSCL until bus idle */ SetIICSCL(0); udelay(1000); i = 10; while ((i > 0) && (GetIICSDA() != 1)) { SetIICSCL(1); udelay(1000); SetIICSCL(0); udelay(1000); i--; } SetIICSCL(1); udelay(1000); /* restore pin functions */ rGPECON = old_gpecon; } /* calculate prescaler and divisor values */ freq = get_PCLK(); if ((freq / pres / (16+1)) > speed) /* set prescaler to 512 */ pres = 512; div = 0; while ((freq / pres / (div+1)) > speed) div++; /* set prescaler, divisor according to freq, also set ACKGEN, IRQ */ rIICCON = (div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0); /* init to SLAVE REVEIVE and set slaveaddr */ rIICSTAT = 0; rIICADD = slaveadd; /* program Master Transmit (and implicit STOP) */ rIICSTAT = IIC_MODE_MT | IIC_TXRX_ENA; } /* cmd_type is 0 for write 1 for read. addr_len can take any value from 0-255, it is only limited by the char, we could make it larger if needed. If it is 0 we skip the address write cycle. */ static int i2c_transfer(unsigned char cmd_type, unsigned char chip, unsigned char addr[], unsigned char addr_len, unsigned char data[], unsigned short data_len) { int i, status, result; if (data == 0 || data_len == 0) { /*Don't support data transfer of no length or to address 0*/ printf( "i2c_transfer: bad call\n" ); return IIC_NOK; } //CheckDelay(); /* Check I2C bus idle */ i = IIC_TIMEOUT * 1000; status = rIICSTAT; while ((i > 0) && (status & IICSTAT_BSY)) { udelay(1000); status = rIICSTAT; i--; } if (status & IICSTAT_BSY) { result = IIC_NOK_TOUT; return(result); } rIICCON |= 0x80; result = IIC_OK; switch (cmd_type) { case IIC_WRITE: if (addr && addr_len) { rIICDS = chip; /* send START */ rIICSTAT = IIC_MODE_MT | IIC_TXRX_ENA | IIC_START_STOP; i = 0; while ((i < addr_len) && (result == IIC_OK)) { result = WaitForXfer(); rIICDS = addr[i]; ReadWriteByte(); i++; } i = 0; while ((i < data_len) && (result == IIC_OK)) { result = WaitForXfer(); rIICDS = data[i]; ReadWriteByte(); i++; } } else { rIICDS = chip; /* send START */ rIICSTAT = IIC_MODE_MT | IIC_TXRX_ENA | IIC_START_STOP; i = 0; while ((i < data_len) && (result = IIC_OK)) { result = WaitForXfer(); rIICDS = data[i]; ReadWriteByte(); i++; } } if (result == IIC_OK) result = WaitForXfer(); /* send STOP */ rIICSTAT = IIC_MODE_MR | IIC_TXRX_ENA; ReadWriteByte(); break; case IIC_READ: if (addr && addr_len) { rIICSTAT = IIC_MODE_MT | IIC_TXRX_ENA; rIICDS = chip; /* send START */ rIICSTAT |= IIC_START_STOP; result = WaitForXfer(); if (IsACK()) { i = 0; while ((i < addr_len) && (result == IIC_OK)) { rIICDS = addr[i]; ReadWriteByte(); result = WaitForXfer(); i++; } rIICDS = chip; /* resend START */ rIICSTAT = IIC_MODE_MR | IIC_TXRX_ENA | IIC_START_STOP; ReadWriteByte(); result = WaitForXfer(); i = 0; while ((i < data_len) && (result == IIC_OK)) { /* disable ACK for final READ */ if (i == data_len - 1) rIICCON &= ~0x80; ReadWriteByte(); result = WaitForXfer(); data[i] = rIICDS; i++; } } else { result = IIC_NACK; } } else { rIICSTAT = IIC_MODE_MR | IIC_TXRX_ENA; rIICDS = chip; /* send START */ rIICSTAT |= IIC_START_STOP; result = WaitForXfer(); if (IsACK()) { i = 0; while ((i < data_len) && (result == IIC_OK)) { /* disable ACK for final READ */ if (i == data_len - 1) rIICCON &= ~0x80; ReadWriteByte(); result = WaitForXfer(); data[i] = rIICDS; i++; } } else { result = IIC_NACK; } } /* send STOP */ rIICSTAT = IIC_MODE_MR | IIC_TXRX_ENA; ReadWriteByte(); break; default: printf( "i2c_transfer: bad call\n" ); result = IIC_NOK; break; } return (result); } int i2c_probe (uchar chip) { uchar buf[1]; buf[0] = 0; /* * What is needed is to send the chip address and verify that the * address was ed (i.e. there was a chip at that address which * drove the data line low). */ return(i2c_transfer (IIC_READ, chip << 1, 0, 0, buf, 1) != IIC_OK); } int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len) { uchar xaddr[4]; int ret; if ( alen > 4 ) { printf ("I2C read: addr len %d not supported\n", alen); return 1; } if ( alen > 0 ) { xaddr[0] = (addr >> 24) & 0xFF; xaddr[1] = (addr >> 16) & 0xFF; xaddr[2] = (addr >> 8) & 0xFF; xaddr[3] = addr & 0xFF; } #ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW /* * EEPROM chips that implement "address overflow" are ones * like Catalyst 24WC04/08/16 which has 9/10/11 bits of * address and the extra bits end up in the "chip address" * bit slots. This makes a 24WC08 (1Kbyte) chip look like * four 256 byte chips. * * Note that we consider the length of the address field to * still be one byte because the extra address bits are * hidden in the chip address. */ if( alen > 0 ) chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW); #endif if( (ret = i2c_transfer(IIC_READ, chip<<1, &xaddr[4-alen], alen, buffer, len )) != 0) { printf( "I2c read: failed %d\n", ret); return 1; } return 0; } int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len) { uchar xaddr[4]; if ( alen > 4 ) { printf ("I2C write: addr len %d not supported\n", alen); return 1; } if ( alen > 0 ) { xaddr[0] = (addr >> 24) & 0xFF; xaddr[1] = (addr >> 16) & 0xFF; xaddr[2] = (addr >> 8) & 0xFF; xaddr[3] = addr & 0xFF; } #ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW /* * EEPROM chips that implement "address overflow" are ones * like Catalyst 24WC04/08/16 which has 9/10/11 bits of * address and the extra bits end up in the "chip address" * bit slots. This makes a 24WC08 (1Kbyte) chip look like * four 256 byte chips. * * Note that we consider the length of the address field to * still be one byte because the extra address bits are * hidden in the chip address. */ if( alen > 0 ) chip |= ((addr >> (alen * 8)) & CFG_I2C_EEPROM_ADDR_OVERFLOW); #endif return (i2c_transfer(IIC_WRITE, chip<<1, &xaddr[4-alen], alen, buffer, len ) != 0); } #endif /* CONFIG_HARD_I2C */ #endif /* CONFIG_DRIVER_S3C24X0_I2C */