/* * i2c.c - driver for Blackfin on-chip TWI/I2C * * Copyright (c) 2006-2008 Analog Devices Inc. * * Licensed under the GPL-2 or later. */ #include <common.h> #ifdef CONFIG_HARD_I2C #include <asm/blackfin.h> #include <i2c.h> #include <asm/io.h> #include <asm/mach-common/bits/twi.h> /* Two-Wire Interface (0xFFC01400 - 0xFFC014FF) */ #ifdef TWI0_CLKDIV #define bfin_read_TWI_CLKDIV() bfin_read_TWI0_CLKDIV() #define bfin_write_TWI_CLKDIV(val) bfin_write_TWI0_CLKDIV(val) #define bfin_read_TWI_CONTROL() bfin_read_TWI0_CONTROL() #define bfin_write_TWI_CONTROL(val) bfin_write_TWI0_CONTROL(val) #define bfin_read_TWI_SLAVE_CTL() bfin_read_TWI0_SLAVE_CTL() #define bfin_write_TWI_SLAVE_CTL(val) bfin_write_TWI0_SLAVE_CTL(val) #define bfin_read_TWI_SLAVE_STAT() bfin_read_TWI0_SLAVE_STAT() #define bfin_write_TWI_SLAVE_STAT(val) bfin_write_TWI0_SLAVE_STAT(val) #define bfin_read_TWI_SLAVE_ADDR() bfin_read_TWI0_SLAVE_ADDR() #define bfin_write_TWI_SLAVE_ADDR(val) bfin_write_TWI0_SLAVE_ADDR(val) #define bfin_read_TWI_MASTER_CTL() bfin_read_TWI0_MASTER_CTL() #define bfin_write_TWI_MASTER_CTL(val) bfin_write_TWI0_MASTER_CTL(val) #define bfin_read_TWI_MASTER_STAT() bfin_read_TWI0_MASTER_STAT() #define bfin_write_TWI_MASTER_STAT(val) bfin_write_TWI0_MASTER_STAT(val) #define bfin_read_TWI_MASTER_ADDR() bfin_read_TWI0_MASTER_ADDR() #define bfin_write_TWI_MASTER_ADDR(val) bfin_write_TWI0_MASTER_ADDR(val) #define bfin_read_TWI_INT_STAT() bfin_read_TWI0_INT_STAT() #define bfin_write_TWI_INT_STAT(val) bfin_write_TWI0_INT_STAT(val) #define bfin_read_TWI_INT_MASK() bfin_read_TWI0_INT_MASK() #define bfin_write_TWI_INT_MASK(val) bfin_write_TWI0_INT_MASK(val) #define bfin_read_TWI_FIFO_CTL() bfin_read_TWI0_FIFO_CTL() #define bfin_write_TWI_FIFO_CTL(val) bfin_write_TWI0_FIFO_CTL(val) #define bfin_read_TWI_FIFO_STAT() bfin_read_TWI0_FIFO_STAT() #define bfin_write_TWI_FIFO_STAT(val) bfin_write_TWI0_FIFO_STAT(val) #define bfin_read_TWI_XMT_DATA8() bfin_read_TWI0_XMT_DATA8() #define bfin_write_TWI_XMT_DATA8(val) bfin_write_TWI0_XMT_DATA8(val) #define bfin_read_TWI_XMT_DATA_16() bfin_read_TWI0_XMT_DATA16() #define bfin_write_TWI_XMT_DATA16(val) bfin_write_TWI0_XMT_DATA16(val) #define bfin_read_TWI_RCV_DATA8() bfin_read_TWI0_RCV_DATA8() #define bfin_write_TWI_RCV_DATA8(val) bfin_write_TWI0_RCV_DATA8(val) #define bfin_read_TWI_RCV_DATA16() bfin_read_TWI0_RCV_DATA16() #define bfin_write_TWI_RCV_DATA16(val) bfin_write_TWI0_RCV_DATA16(val) #endif #ifdef DEBUG_I2C #define PRINTD(fmt,args...) do { \ DECLARE_GLOBAL_DATA_PTR; \ if (gd->have_console) \ printf(fmt ,##args); \ } while (0) #else #define PRINTD(fmt,args...) #endif #ifndef CONFIG_TWICLK_KHZ #define CONFIG_TWICLK_KHZ 50 #endif /* All transfers are described by this data structure */ struct i2c_msg { u16 addr; /* slave address */ u16 flags; #define I2C_M_STOP 0x2 #define I2C_M_RD 0x1 u16 len; /* msg length */ u8 *buf; /* pointer to msg data */ }; /** * i2c_reset: - reset the host controller */ static void i2c_reset(void) { /* Disable TWI */ bfin_write_TWI_CONTROL(0); SSYNC(); /* Set TWI internal clock as 10MHz */ bfin_write_TWI_CONTROL(((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F); /* Set Twi interface clock as specified */ if (CONFIG_TWICLK_KHZ > 400) bfin_write_TWI_CLKDIV(((5 * 1024 / 400) << 8) | ((5 * 1024 / 400) & 0xFF)); else bfin_write_TWI_CLKDIV(((5 * 1024 / CONFIG_TWICLK_KHZ) << 8) | ((5 * 1024 / CONFIG_TWICLK_KHZ) & 0xFF)); /* Enable TWI */ bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA); SSYNC(); } int wait_for_completion(struct i2c_msg *msg, int timeout_count) { unsigned short twi_int_stat; unsigned short mast_stat; int i; for (i = 0; i < timeout_count; i++) { twi_int_stat = bfin_read_TWI_INT_STAT(); mast_stat = bfin_read_TWI_MASTER_STAT(); if (XMTSERV & twi_int_stat) { /* Transmit next data */ if (msg->len > 0) { bfin_write_TWI_XMT_DATA8(*(msg->buf++)); msg->len--; } else if (msg->flags & I2C_M_STOP) bfin_write_TWI_MASTER_CTL (bfin_read_TWI_MASTER_CTL() | STOP); SSYNC(); /* Clear status */ bfin_write_TWI_INT_STAT(XMTSERV); SSYNC(); i = 0; } if (RCVSERV & twi_int_stat) { if (msg->len > 0) { /* Receive next data */ *(msg->buf++) = bfin_read_TWI_RCV_DATA8(); msg->len--; } else if (msg->flags & I2C_M_STOP) { bfin_write_TWI_MASTER_CTL (bfin_read_TWI_MASTER_CTL() | STOP); SSYNC(); } /* Clear interrupt source */ bfin_write_TWI_INT_STAT(RCVSERV); SSYNC(); i = 0; } if (MERR & twi_int_stat) { bfin_write_TWI_INT_STAT(MERR); bfin_write_TWI_INT_MASK(0); bfin_write_TWI_MASTER_STAT(0x3e); bfin_write_TWI_MASTER_CTL(0); SSYNC(); /* * if both err and complete int stats are set, * return proper results. */ if (MCOMP & twi_int_stat) { bfin_write_TWI_INT_STAT(MCOMP); bfin_write_TWI_INT_MASK(0); bfin_write_TWI_MASTER_CTL(0); SSYNC(); /* * If it is a quick transfer, * only address bug no data, not an err. */ if (msg->len == 0 && mast_stat & BUFRDERR) return 0; /* * If address not acknowledged return -3, * else return 0. */ else if (!(mast_stat & ANAK)) return 0; else return -3; } return -1; } if (MCOMP & twi_int_stat) { bfin_write_TWI_INT_STAT(MCOMP); SSYNC(); bfin_write_TWI_INT_MASK(0); bfin_write_TWI_MASTER_CTL(0); SSYNC(); return 0; } } if (msg->flags & I2C_M_RD) return -4; else return -2; } /** * 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: transfer fail * -2: transmit timeout * -3: ACK missing * -4: receive timeout * -5: controller not ready */ int i2c_transfer(struct i2c_msg *msg) { int ret = 0; int timeout_count = 10000; int len = msg->len; if (!(bfin_read_TWI_CONTROL() & TWI_ENA)) { ret = -5; goto transfer_error; } while (bfin_read_TWI_MASTER_STAT() & BUSBUSY) continue; /* Set Transmit device address */ bfin_write_TWI_MASTER_ADDR(msg->addr); /* * FIFO Initiation. * Data in FIFO should be discarded before start a new operation. */ bfin_write_TWI_FIFO_CTL(0x3); SSYNC(); bfin_write_TWI_FIFO_CTL(0); SSYNC(); if (!(msg->flags & I2C_M_RD)) { /* Transmit first data */ if (msg->len > 0) { PRINTD("1 in i2c_transfer: buf=%d, len=%d\n", *msg->buf, len); bfin_write_TWI_XMT_DATA8(*(msg->buf++)); msg->len--; SSYNC(); } } /* clear int stat */ bfin_write_TWI_INT_STAT(MERR | MCOMP | XMTSERV | RCVSERV); /* Interrupt mask . Enable XMT, RCV interrupt */ bfin_write_TWI_INT_MASK(MCOMP | MERR | ((msg->flags & I2C_M_RD) ? RCVSERV : XMTSERV)); SSYNC(); if (len > 0 && len <= 255) bfin_write_TWI_MASTER_CTL((len << 6)); else if (msg->len > 255) { bfin_write_TWI_MASTER_CTL((0xff << 6)); msg->flags &= I2C_M_STOP; } else bfin_write_TWI_MASTER_CTL(0); /* Master enable */ bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN | ((msg->flags & I2C_M_RD) ? MDIR : 0) | ((CONFIG_TWICLK_KHZ > 100) ? FAST : 0)); SSYNC(); ret = wait_for_completion(msg, timeout_count); PRINTD("3 in i2c_transfer: ret=%d\n", ret); transfer_error: switch (ret) { case 1: PRINTD(("i2c_transfer: error: transfer fail\n")); break; case 2: PRINTD(("i2c_transfer: error: transmit timeout\n")); break; case 3: PRINTD(("i2c_transfer: error: ACK missing\n")); break; case 4: PRINTD(("i2c_transfer: error: receive timeout\n")); break; case 5: PRINTD(("i2c_transfer: error: controller not ready\n")); i2c_reset(); break; default: break; } return ret; } /* ---------------------------------------------------------------------*/ /* API Functions */ /* ---------------------------------------------------------------------*/ void i2c_init(int speed, int slaveaddr) { i2c_reset(); } /** * 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; u8 probebuf; i2c_reset(); probebuf = 0; msg.addr = chip; msg.flags = 0; msg.len = 1; msg.buf = &probebuf; if (i2c_transfer(&msg)) return -1; msg.addr = chip; msg.flags = I2C_M_RD; msg.len = 1; msg.buf = &probebuf; if (i2c_transfer(&msg)) return -1; return 0; } /** * i2c_read: - Read multiple bytes from an i2c device * * chip: I2C chip address, range 0..127 * addr: Memory (register) address within the chip * alen: Number of bytes to use for addr (typically 1, 2 for larger * memories, 0 for register type devices with only one * register) * buffer: Where to read/write the data * len: How many bytes to read/write * * Returns: 0 on success, not 0 on failure */ 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 */ PRINTD("i2c_read: chip=0x%x, addr=0x%x, alen=0x%x, len=0x%x\n", chip, addr, alen, len); if (alen > 0) { addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF); addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF); addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF); msg.addr = chip; msg.flags = 0; msg.len = alen; msg.buf = addr_bytes; if (i2c_transfer(&msg)) return -1; } /* start read sequence */ PRINTD(("i2c_read: start read sequence\n")); msg.addr = chip; msg.flags = I2C_M_RD; msg.len = len; msg.buf = buffer; if (i2c_transfer(&msg)) return -1; return 0; } /** * i2c_write: - Write multiple bytes to an i2c device * * chip: I2C chip address, range 0..127 * addr: Memory (register) address within the chip * alen: Number of bytes to use for addr (typically 1, 2 for larger * memories, 0 for register type devices with only one * register) * buffer: Where to read/write the data * len: How many bytes to read/write * * Returns: 0 on success, not 0 on failure */ 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%x, addr=0x%x, alen=0x%x, len=0x%x, buf0=0x%x\n", chip, addr, alen, len, buffer[0]); /* chip address write */ if (alen > 0) { addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF); addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF); addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF); msg.addr = chip; msg.flags = 0; msg.len = alen; msg.buf = addr_bytes; if (i2c_transfer(&msg)) return -1; } /* start read sequence */ PRINTD(("i2c_write: start write sequence\n")); msg.addr = chip; msg.flags = 0; msg.len = len; msg.buf = buffer; if (i2c_transfer(&msg)) return -1; return 0; } #endif /* CONFIG_HARD_I2C */