/* * (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 #include #include #include #ifdef CONFIG_HARD_I2C #define I2C_WRITE 0 #define I2C_READ 1 #define I2C_OK 0 #define I2C_NOK 1 #define I2C_NACK 2 #define I2C_NOK_LA 3 /* Lost arbitration */ #define I2C_NOK_TOUT 4 /* time out */ #define I2CSTAT_BSY 0x20 /* Busy bit */ #define I2CSTAT_NACK 0x01 /* Nack bit */ #define I2CCON_IRPND 0x10 /* Interrupt pending bit */ #define I2C_MODE_MT 0xC0 /* Master Transmit Mode */ #define I2C_MODE_MR 0x80 /* Master Receive Mode */ #define I2C_START_STOP 0x20 /* START / STOP */ #define I2C_TXRX_ENA 0x10 /* I2C Tx/Rx enable */ #define I2C_TIMEOUT 1 /* 1 second */ static int GetI2CSDA(void) { struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio(); #ifdef CONFIG_S3C2410 return (readl(&gpio->GPEDAT) & 0x8000) >> 15; #endif #ifdef CONFIG_S3C2400 return (readl(&gpio->PGDAT) & 0x0020) >> 5; #endif } #if 0 static void SetI2CSDA(int x) { rGPEDAT = (rGPEDAT & ~0x8000) | (x & 1) << 15; } #endif static void SetI2CSCL(int x) { struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio(); #ifdef CONFIG_S3C2410 writel((readl(&gpio->GPEDAT) & ~0x4000) | (x & 1) << 14, &gpio->GPEDAT); #endif #ifdef CONFIG_S3C2400 writel((readl(&gpio->PGDAT) & ~0x0040) | (x & 1) << 6, &gpio->PGDAT); #endif } static int WaitForXfer(void) { struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c(); int i; i = I2C_TIMEOUT * 10000; while (!(readl(&i2c->IICCON) & I2CCON_IRPND) && (i > 0)) { udelay(100); i--; } return (readl(&i2c->IICCON) & I2CCON_IRPND) ? I2C_OK : I2C_NOK_TOUT; } static int IsACK(void) { struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c(); return !(readl(&i2c->IICSTAT) & I2CSTAT_NACK); } static void ReadWriteByte(void) { struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c(); writel(readl(&i2c->IICCON) & ~I2CCON_IRPND, &i2c->IICCON); } void i2c_init(int speed, int slaveadd) { struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c(); struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio(); ulong freq, pres = 16, div; int i; /* wait for some time to give previous transfer a chance to finish */ i = I2C_TIMEOUT * 1000; while ((readl(&i2c->IICSTAT) && I2CSTAT_BSY) && (i > 0)) { udelay(1000); i--; } if ((readl(&i2c->IICSTAT) & I2CSTAT_BSY) || GetI2CSDA() == 0) { #ifdef CONFIG_S3C2410 ulong old_gpecon = readl(&gpio->GPECON); #endif #ifdef CONFIG_S3C2400 ulong old_gpecon = readl(&gpio->PGCON); #endif /* bus still busy probably by (most) previously interrupted transfer */ #ifdef CONFIG_S3C2410 /* set I2CSDA and I2CSCL (GPE15, GPE14) to GPIO */ writel((readl(&gpio->GPECON) & ~0xF0000000) | 0x10000000, &gpio->GPECON); #endif #ifdef CONFIG_S3C2400 /* set I2CSDA and I2CSCL (PG5, PG6) to GPIO */ writel((readl(&gpio->PGCON) & ~0x00003c00) | 0x00001000, &gpio->PGCON); #endif /* toggle I2CSCL until bus idle */ SetI2CSCL(0); udelay(1000); i = 10; while ((i > 0) && (GetI2CSDA() != 1)) { SetI2CSCL(1); udelay(1000); SetI2CSCL(0); udelay(1000); i--; } SetI2CSCL(1); udelay(1000); /* restore pin functions */ #ifdef CONFIG_S3C2410 writel(old_gpecon, &gpio->GPECON); #endif #ifdef CONFIG_S3C2400 writel(old_gpecon, &gpio->PGCON); #endif } /* 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 */ writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->IICCON); /* init to SLAVE REVEIVE and set slaveaddr */ writel(0, &i2c->IICSTAT); writel(slaveadd, &i2c->IICADD); /* program Master Transmit (and implicit STOP) */ writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->IICSTAT); } /* * 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) { struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c(); int i, 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 I2C_NOK; } /* Check I2C bus idle */ i = I2C_TIMEOUT * 1000; while ((readl(&i2c->IICSTAT) & I2CSTAT_BSY) && (i > 0)) { udelay(1000); i--; } if (readl(&i2c->IICSTAT) & I2CSTAT_BSY) return I2C_NOK_TOUT; writel(readl(&i2c->IICCON) | 0x80, &i2c->IICCON); result = I2C_OK; switch (cmd_type) { case I2C_WRITE: if (addr && addr_len) { writel(chip, &i2c->IICDS); /* send START */ writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP, &i2c->IICSTAT); i = 0; while ((i < addr_len) && (result == I2C_OK)) { result = WaitForXfer(); writel(addr[i], &i2c->IICDS); ReadWriteByte(); i++; } i = 0; while ((i < data_len) && (result == I2C_OK)) { result = WaitForXfer(); writel(data[i], &i2c->IICDS); ReadWriteByte(); i++; } } else { writel(chip, &i2c->IICDS); /* send START */ writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP, &i2c->IICSTAT); i = 0; while ((i < data_len) && (result = I2C_OK)) { result = WaitForXfer(); writel(data[i], &i2c->IICDS); ReadWriteByte(); i++; } } if (result == I2C_OK) result = WaitForXfer(); /* send STOP */ writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->IICSTAT); ReadWriteByte(); break; case I2C_READ: if (addr && addr_len) { writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->IICSTAT); writel(chip, &i2c->IICDS); /* send START */ writel(readl(&i2c->IICSTAT) | I2C_START_STOP, &i2c->IICSTAT); result = WaitForXfer(); if (IsACK()) { i = 0; while ((i < addr_len) && (result == I2C_OK)) { writel(addr[i], &i2c->IICDS); ReadWriteByte(); result = WaitForXfer(); i++; } writel(chip, &i2c->IICDS); /* resend START */ writel(I2C_MODE_MR | I2C_TXRX_ENA | I2C_START_STOP, &i2c->IICSTAT); ReadWriteByte(); result = WaitForXfer(); i = 0; while ((i < data_len) && (result == I2C_OK)) { /* disable ACK for final READ */ if (i == data_len - 1) writel(readl(&i2c->IICCON) & ~0x80, &i2c->IICCON); ReadWriteByte(); result = WaitForXfer(); data[i] = readl(&i2c->IICDS); i++; } } else { result = I2C_NACK; } } else { writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->IICSTAT); writel(chip, &i2c->IICDS); /* send START */ writel(readl(&i2c->IICSTAT) | I2C_START_STOP, &i2c->IICSTAT); result = WaitForXfer(); if (IsACK()) { i = 0; while ((i < data_len) && (result == I2C_OK)) { /* disable ACK for final READ */ if (i == data_len - 1) writel(readl(&i2c->IICCON) & ~0x80, &i2c->IICCON); ReadWriteByte(); result = WaitForXfer(); data[i] = readl(&i2c->IICDS); i++; } } else { result = I2C_NACK; } } /* send STOP */ writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->IICSTAT); ReadWriteByte(); break; default: printf("i2c_transfer: bad call\n"); result = I2C_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(I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_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 CONFIG_SYS_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)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW); #endif if ((ret = i2c_transfer(I2C_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 CONFIG_SYS_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)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW); #endif return (i2c_transfer (I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer, len) != 0); } #endif /* CONFIG_HARD_I2C */