diff options
Diffstat (limited to 'cpu/mpc85xx/i2c.c')
| -rw-r--r-- | cpu/mpc85xx/i2c.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/cpu/mpc85xx/i2c.c b/cpu/mpc85xx/i2c.c new file mode 100644 index 0000000..ae08d18 --- /dev/null +++ b/cpu/mpc85xx/i2c.c @@ -0,0 +1,288 @@ +/* + * (C) Copyright 2003,Motorola Inc. + * Xianghua Xiao <x.xiao@motorola.com> + * Adapted for Motorola 85xx chip. + * + * (C) Copyright 2003 + * Gleb Natapov <gnatapov@mrv.com> + * Some bits are taken from linux driver writen by adrian@humboldt.co.uk + * + * Hardware I2C driver for MPC107 PCI bridge. + * + * 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 + */ + +#include <common.h> +#include <command.h> + +#define DEBUG + +#if defined(DEBUG) +#define DEB(x) x +#else +#define DEB(x) +#endif + +#ifdef CONFIG_HARD_I2C +#include <i2c.h> + +#define TIMEOUT (CFG_HZ/4) + +#define I2C_Addr ((unsigned *)(CFG_CCSRBAR + 0x3000)) + +#define I2CADR &I2C_Addr[0] +#define I2CFDR &I2C_Addr[1] +#define I2CCCR &I2C_Addr[2] +#define I2CCSR &I2C_Addr[3] +#define I2CCDR &I2C_Addr[4] +#define I2CDFSRR &I2C_Addr[5] + +#define I2C_READ 1 +#define I2C_WRITE 0 + +/* taken from linux include/asm-ppc/io.h */ +inline unsigned in_le32(volatile unsigned *addr) +{ + unsigned ret; + + __asm__ __volatile__("lwbrx %0,0,%1;\n" + "twi 0,%0,0;\n" + "isync" : "=r" (ret) : + "r" (addr), "m" (*addr)); + return ret; +} + +inline void out_le32(volatile unsigned *addr, int val) +{ + __asm__ __volatile__("stwbrx %1,0,%2; eieio" : "=m" (*addr) : + "r" (val), "r" (addr)); +} + +#define writel(val, addr) out_le32(addr, val) +#define readl(addr) in_le32(addr) + +void +i2c_init(int speed, int slaveadd) +{ + /* stop I2C controller */ + writel (0x0, I2CCCR); + /* set clock */ + writel (0x3f, I2CFDR); + /* set default filter */ + writel (0x10,I2CDFSRR); + /* write slave address */ + writel (slaveadd, I2CADR); + /* clear status register */ + writel (0x0, I2CCSR); + /* start I2C controller */ + writel (MPC85xx_I2CCR_MEN, I2CCCR); +} + +static __inline__ int +i2c_wait4bus (void) +{ + ulong timeval = get_timer (0); + + while (readl (I2CCSR) & MPC85xx_I2CSR_MBB) + if (get_timer (timeval) > TIMEOUT) + return -1; + + return 0; +} + +static __inline__ int +i2c_wait (int write) +{ + u32 csr; + ulong timeval = get_timer (0); + + do + { + csr = readl (I2CCSR); + + if (!(csr & MPC85xx_I2CSR_MIF)) + continue; + + writel (0x0, I2CCSR); + + if (csr & MPC85xx_I2CSR_MAL) + { + DEB(printf ("i2c_wait: MAL\n")); + return -1; + } + + if (!(csr & MPC85xx_I2CSR_MCF)) + { + DEB(printf ("i2c_wait: unfinished\n")); + return -1; + } + + if (write == I2C_WRITE && (csr & MPC85xx_I2CSR_RXAK)) + { + DEB(printf ("i2c_wait: No RXACK\n")); + return -1; + } + + return 0; + } while (get_timer (timeval) < TIMEOUT); + + DEB(printf ("i2c_wait: timed out\n")); + return -1; +} + +static __inline__ int +i2c_write_addr (u8 dev, u8 dir, int rsta) +{ + writel (MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | MPC85xx_I2CCR_MTX | + (rsta?MPC85xx_I2CCR_RSTA:0), I2CCCR); + + writel ((dev << 1) | dir, I2CCDR); + + if (i2c_wait (I2C_WRITE) < 0) + return 0; + + return 1; +} + +static __inline__ int +__i2c_write (u8 *data, int length) +{ + int i; + + writel (MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | MPC85xx_I2CCR_MTX, I2CCCR); + + for (i=0; i < length; i++) + { + writel (data[i], I2CCDR); + + if (i2c_wait (I2C_WRITE) < 0) + break; + } + + return i; +} + +static __inline__ int +__i2c_read (u8 *data, int length) +{ + int i; + + writel (MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | + ((length == 1) ? MPC85xx_I2CCR_TXAK : 0), I2CCCR); + + /* dummy read */ + readl (I2CCDR); + + for (i=0; i < length; i++) + { + if (i2c_wait (I2C_READ) < 0) + break; + + /* Generate ack on last next to last byte */ + if (i == length - 2) + writel (MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | + MPC85xx_I2CCR_TXAK, I2CCCR); + + /* Generate stop on last byte */ + if (i == length - 1) + writel (MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_TXAK, I2CCCR); + + data[i] = readl (I2CCDR); + } + + return i; +} + +int +i2c_read (u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = 0; + u8 *a = (u8*)&addr; + + if (i2c_wait4bus () < 0) + goto exit; + + if (i2c_write_addr (dev, I2C_WRITE, 0) == 0) + goto exit; + + if (__i2c_write (&a[4 - alen], alen) != alen) + goto exit; + + if (i2c_write_addr (dev, I2C_READ, 1) == 0) + goto exit; + + i = __i2c_read (data, length); + + exit: + writel (MPC85xx_I2CCR_MEN, I2CCCR); + + return !(i == length); +} + +int +i2c_write (u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = 0; + u8 *a = (u8*)&addr; + + if (i2c_wait4bus () < 0) + goto exit; + + if (i2c_write_addr (dev, I2C_WRITE, 0) == 0) + goto exit; + + if (__i2c_write (&a[4 - alen], alen) != alen) + goto exit; + + i = __i2c_write (data, length); + + exit: + writel (MPC85xx_I2CCR_MEN, I2CCCR); + + return !(i == length); +} + +int i2c_probe (uchar chip) +{ + int tmp; + + /* + * Try to read the first location of the chip. The underlying + * driver doesn't appear to support sending just the chip address + * and looking for an <ACK> back. + */ + udelay(10000); + return i2c_read (chip, 0, 1, (char *)&tmp, 1); +} + +uchar i2c_reg_read (uchar i2c_addr, uchar reg) +{ + char buf[1]; + + i2c_read (i2c_addr, reg, 1, buf, 1); + + return (buf[0]); +} + +void i2c_reg_write (uchar i2c_addr, uchar reg, uchar val) +{ + i2c_write (i2c_addr, reg, 1, &val, 1); +} + +#endif /* CONFIG_HARD_I2C */ |