diff options
Diffstat (limited to 'arch/ppc/cpu/mpc824x/drivers/i2c/i2c.c')
| -rw-r--r-- | arch/ppc/cpu/mpc824x/drivers/i2c/i2c.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/arch/ppc/cpu/mpc824x/drivers/i2c/i2c.c b/arch/ppc/cpu/mpc824x/drivers/i2c/i2c.c new file mode 100644 index 0000000..637ae4c --- /dev/null +++ b/arch/ppc/cpu/mpc824x/drivers/i2c/i2c.c @@ -0,0 +1,270 @@ +/* + * (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> + +#undef I2CDBG + +#ifdef CONFIG_HARD_I2C +#include <i2c.h> + +#define TIMEOUT (CONFIG_SYS_HZ/4) + +#define I2C_Addr ((unsigned *)(CONFIG_SYS_EUMB_ADDR + 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 MPC107_CCR_MEN 0x80 +#define MPC107_CCR_MIEN 0x40 +#define MPC107_CCR_MSTA 0x20 +#define MPC107_CCR_MTX 0x10 +#define MPC107_CCR_TXAK 0x08 +#define MPC107_CCR_RSTA 0x04 + +#define MPC107_CSR_MCF 0x80 +#define MPC107_CSR_MAAS 0x40 +#define MPC107_CSR_MBB 0x20 +#define MPC107_CSR_MAL 0x10 +#define MPC107_CSR_SRW 0x04 +#define MPC107_CSR_MIF 0x02 +#define MPC107_CSR_RXAK 0x01 + +#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 (0x1020, I2CFDR); + /* write slave address */ + writel (slaveadd, I2CADR); + /* clear status register */ + writel (0x0, I2CCSR); + /* start I2C controller */ + writel (MPC107_CCR_MEN, I2CCCR); + + return; +} + +static __inline__ int i2c_wait4bus (void) +{ + ulong timeval = get_timer (0); + + while (readl (I2CCSR) & MPC107_CSR_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 & MPC107_CSR_MIF)) + continue; + + writel (0x0, I2CCSR); + + if (csr & MPC107_CSR_MAL) { +#ifdef I2CDBG + printf ("i2c_wait: MAL\n"); +#endif + return -1; + } + + if (!(csr & MPC107_CSR_MCF)) { +#ifdef I2CDBG + printf ("i2c_wait: unfinished\n"); +#endif + return -1; + } + + if (write == I2C_WRITE && (csr & MPC107_CSR_RXAK)) { +#ifdef I2CDBG + printf ("i2c_wait: No RXACK\n"); +#endif + return -1; + } + + return 0; + } while (get_timer (timeval) < TIMEOUT); + +#ifdef I2CDBG + printf ("i2c_wait: timed out\n"); +#endif + return -1; +} + +static __inline__ int i2c_write_addr (u8 dev, u8 dir, int rsta) +{ + writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX | + (rsta ? MPC107_CCR_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 (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_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 (MPC107_CCR_MEN | MPC107_CCR_MSTA | + ((length == 1) ? MPC107_CCR_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 (MPC107_CCR_MEN | MPC107_CCR_MSTA | + MPC107_CCR_TXAK, I2CCCR); + + /* Generate stop on last byte */ + if (i == length - 1) + writel (MPC107_CCR_MEN | MPC107_CCR_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 (MPC107_CCR_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 (MPC107_CCR_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, (uchar *) &tmp, 1); +} + +#endif /* CONFIG_HARD_I2C */ |