diff options
Diffstat (limited to 'drivers/fsl_i2c.c')
| -rw-r--r-- | drivers/fsl_i2c.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/fsl_i2c.c b/drivers/fsl_i2c.c new file mode 100644 index 0000000..72b2556 --- /dev/null +++ b/drivers/fsl_i2c.c @@ -0,0 +1,247 @@ +/* + * Copyright 2006 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * Version 2 as published by the Free Software Foundation. + * + * 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> + +#ifdef CONFIG_HARD_I2C + +#include <asm/io.h> +#include <asm/fsl_i2c.h> + +#define I2C_TIMEOUT (CFG_HZ / 4) + +#define I2C ((struct fsl_i2c *)(CFG_IMMR + CFG_I2C_OFFSET)) + + +void +i2c_init(int speed, int slaveadd) +{ + /* stop I2C controller */ + writeb(0x0 , &I2C->cr); + + /* set clock */ + writeb(0x3f, &I2C->fdr); + + /* set default filter */ + writeb(0x10, &I2C->dfsrr); + + /* write slave address */ + writeb(slaveadd, &I2C->adr); + + /* clear status register */ + writeb(0x0, &I2C->sr); + + /* start I2C controller */ + writeb(I2C_CR_MEN, &I2C->cr); +} + +static __inline__ int +i2c_wait4bus(void) +{ + ulong timeval = get_timer (0); + + while (readb(&I2C->sr) & I2C_SR_MBB) { + if (get_timer(timeval) > I2C_TIMEOUT) { + return -1; + } + } + + return 0; +} + +static __inline__ int +i2c_wait(int write) +{ + u32 csr; + ulong timeval = get_timer(0); + + do { + csr = readb(&I2C->sr); + if (!(csr & I2C_SR_MIF)) + continue; + + writeb(0x0, &I2C->sr); + + if (csr & I2C_SR_MAL) { + debug("i2c_wait: MAL\n"); + return -1; + } + + if (!(csr & I2C_SR_MCF)) { + debug("i2c_wait: unfinished\n"); + return -1; + } + + if (write == I2C_WRITE && (csr & I2C_SR_RXAK)) { + debug("i2c_wait: No RXACK\n"); + return -1; + } + + return 0; + } while (get_timer (timeval) < I2C_TIMEOUT); + + debug("i2c_wait: timed out\n"); + return -1; +} + +static __inline__ int +i2c_write_addr (u8 dev, u8 dir, int rsta) +{ + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX + | (rsta ? I2C_CR_RSTA : 0), + &I2C->cr); + + writeb((dev << 1) | dir, &I2C->dr); + + if (i2c_wait(I2C_WRITE) < 0) + return 0; + + return 1; +} + +static __inline__ int +__i2c_write(u8 *data, int length) +{ + int i; + + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX, + &I2C->cr); + + for (i = 0; i < length; i++) { + writeb(data[i], &I2C->dr); + + if (i2c_wait(I2C_WRITE) < 0) + break; + } + + return i; +} + +static __inline__ int +__i2c_read(u8 *data, int length) +{ + int i; + + writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0), + &I2C->cr); + + /* dummy read */ + readb(&I2C->dr); + + 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) + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK, + &I2C->cr); + + /* Generate stop on last byte */ + if (i == length - 1) + writeb(I2C_CR_MEN | I2C_CR_TXAK, &I2C->cr); + + data[i] = readb(&I2C->dr); + } + + 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: + writeb(I2C_CR_MEN, &I2C->cr); + + 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: + writeb(I2C_CR_MEN, &I2C->cr); + + 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); +} + +uchar +i2c_reg_read(uchar i2c_addr, uchar reg) +{ + uchar 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 */ |