diff options
Diffstat (limited to 'drivers/i2c/fsl_i2c.c')
| -rw-r--r-- | drivers/i2c/fsl_i2c.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c new file mode 100644 index 0000000..22485ea --- /dev/null +++ b/drivers/i2c/fsl_i2c.c @@ -0,0 +1,295 @@ +/* + * 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> + +#ifdef CONFIG_FSL_I2C +#ifdef CONFIG_HARD_I2C + +#include <command.h> +#include <i2c.h> /* Functional interface */ + +#include <asm/io.h> +#include <asm/fsl_i2c.h> /* HW definitions */ + +#define I2C_TIMEOUT (CFG_HZ / 4) + +#define I2C_READ_BIT 1 +#define I2C_WRITE_BIT 0 + +/* Initialize the bus pointer to whatever one the SPD EEPROM is on. + * Default is bus 0. This is necessary because the DDR initialization + * runs from ROM, and we can't switch buses because we can't modify + * the global variables. + */ +#ifdef CFG_SPD_BUS_NUM +static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = CFG_SPD_BUS_NUM; +#else +static unsigned int i2c_bus_num __attribute__ ((section ("data"))) = 0; +#endif + +static volatile struct fsl_i2c *i2c_dev[2] = { + (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET), +#ifdef CFG_I2C2_OFFSET + (struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET) +#endif +}; + +void +i2c_init(int speed, int slaveadd) +{ + volatile struct fsl_i2c *dev; + + dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C_OFFSET); + + writeb(0, &dev->cr); /* stop I2C controller */ + udelay(5); /* let it shutdown in peace */ + writeb(0x3F, &dev->fdr); /* set bus speed */ + writeb(0x3F, &dev->dfsrr); /* set default filter */ + writeb(slaveadd << 1, &dev->adr); /* write slave address */ + writeb(0x0, &dev->sr); /* clear status register */ + writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ + +#ifdef CFG_I2C2_OFFSET + dev = (struct fsl_i2c *) (CFG_IMMR + CFG_I2C2_OFFSET); + + writeb(0, &dev->cr); /* stop I2C controller */ + udelay(5); /* let it shutdown in peace */ + writeb(0x3F, &dev->fdr); /* set bus speed */ + writeb(0x3F, &dev->dfsrr); /* set default filter */ + writeb(slaveadd << 1, &dev->adr); /* write slave address */ + writeb(0x0, &dev->sr); /* clear status register */ + writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ +#endif /* CFG_I2C2_OFFSET */ +} + +static __inline__ int +i2c_wait4bus(void) +{ + ulong timeval = get_timer(0); + + while (readb(&i2c_dev[i2c_bus_num]->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_dev[i2c_bus_num]->sr); + if (!(csr & I2C_SR_MIF)) + continue; + + writeb(0x0, &i2c_dev[i2c_bus_num]->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_BIT && (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_dev[i2c_bus_num]->cr); + + writeb((dev << 1) | dir, &i2c_dev[i2c_bus_num]->dr); + + if (i2c_wait(I2C_WRITE_BIT) < 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_dev[i2c_bus_num]->cr); + + for (i = 0; i < length; i++) { + writeb(data[i], &i2c_dev[i2c_bus_num]->dr); + + if (i2c_wait(I2C_WRITE_BIT) < 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_dev[i2c_bus_num]->cr); + + /* dummy read */ + readb(&i2c_dev[i2c_bus_num]->dr); + + for (i = 0; i < length; i++) { + if (i2c_wait(I2C_READ_BIT) < 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_dev[i2c_bus_num]->cr); + + /* Generate stop on last byte */ + if (i == length - 1) + writeb(I2C_CR_MEN | I2C_CR_TXAK, &i2c_dev[i2c_bus_num]->cr); + + data[i] = readb(&i2c_dev[i2c_bus_num]->dr); + } + + return i; +} + +int +i2c_read(u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = -1; /* signal error */ + u8 *a = (u8*)&addr; + + if (i2c_wait4bus() >= 0 + && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 + && __i2c_write(&a[4 - alen], alen) == alen) + i = 0; /* No error so far */ + + if (length + && i2c_write_addr(dev, I2C_READ_BIT, 1) != 0) + i = __i2c_read(data, length); + + writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); + + if (i == length) + return 0; + + return -1; +} + +int +i2c_write(u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = -1; /* signal error */ + u8 *a = (u8*)&addr; + + if (i2c_wait4bus() >= 0 + && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 + && __i2c_write(&a[4 - alen], alen) == alen) { + i = __i2c_write(data, length); + } + + writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); + + if (i == length) + return 0; + + return -1; +} + +int +i2c_probe(uchar chip) +{ + /* For unknow reason the controller will ACK when + * probing for a slave with the same address, so skip + * it. + */ + if (chip == (readb(&i2c_dev[i2c_bus_num]->adr) >> 1)) + return -1; + + return i2c_read(chip, 0, 0, NULL, 0); +} + +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); +} + +int i2c_set_bus_num(unsigned int bus) +{ +#ifdef CFG_I2C2_OFFSET + if (bus > 1) { +#else + if (bus > 0) { +#endif + return -1; + } + + i2c_bus_num = bus; + + return 0; +} + +int i2c_set_bus_speed(unsigned int speed) +{ + return -1; +} + +unsigned int i2c_get_bus_num(void) +{ + return i2c_bus_num; +} + +unsigned int i2c_get_bus_speed(void) +{ + return 0; +} +#endif /* CONFIG_HARD_I2C */ +#endif /* CONFIG_FSL_I2C */ |