diff options
Diffstat (limited to 'drivers/i2c/davinci_i2c.c')
| -rw-r--r-- | drivers/i2c/davinci_i2c.c | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/drivers/i2c/davinci_i2c.c b/drivers/i2c/davinci_i2c.c new file mode 100644 index 0000000..eee1cbd --- /dev/null +++ b/drivers/i2c/davinci_i2c.c @@ -0,0 +1,329 @@ +/* + * TI DaVinci (TMS320DM644x) I2C driver. + * + * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net> + * + * -------------------------------------------------------- + * + * 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 <i2c.h> +#include <asm/arch/hardware.h> +#include <asm/arch/i2c_defs.h> + +#define CHECK_NACK() \ + do {\ + if (tmp & (I2C_TIMEOUT | I2C_STAT_NACK)) {\ + REG(I2C_CON) = 0;\ + return(1);\ + }\ + } while (0) + + +static int wait_for_bus(void) +{ + int stat, timeout; + + REG(I2C_STAT) = 0xffff; + + for (timeout = 0; timeout < 10; timeout++) { + if (!((stat = REG(I2C_STAT)) & I2C_STAT_BB)) { + REG(I2C_STAT) = 0xffff; + return(0); + } + + REG(I2C_STAT) = stat; + udelay(50000); + } + + REG(I2C_STAT) = 0xffff; + return(1); +} + + +static int poll_i2c_irq(int mask) +{ + int stat, timeout; + + for (timeout = 0; timeout < 10; timeout++) { + udelay(1000); + stat = REG(I2C_STAT); + if (stat & mask) { + return(stat); + } + } + + REG(I2C_STAT) = 0xffff; + return(stat | I2C_TIMEOUT); +} + + +void flush_rx(void) +{ + int dummy; + + while (1) { + if (!(REG(I2C_STAT) & I2C_STAT_RRDY)) + break; + + dummy = REG(I2C_DRR); + REG(I2C_STAT) = I2C_STAT_RRDY; + udelay(1000); + } +} + + +void i2c_init(int speed, int slaveadd) +{ + u_int32_t div, psc; + + if (REG(I2C_CON) & I2C_CON_EN) { + REG(I2C_CON) = 0; + udelay (50000); + } + + psc = 2; + div = (CONFIG_SYS_HZ_CLOCK / ((psc + 1) * speed)) - 10; /* SCLL + SCLH */ + REG(I2C_PSC) = psc; /* 27MHz / (2 + 1) = 9MHz */ + REG(I2C_SCLL) = (div * 50) / 100; /* 50% Duty */ + REG(I2C_SCLH) = div - REG(I2C_SCLL); + + REG(I2C_OA) = slaveadd; + REG(I2C_CNT) = 0; + + /* Interrupts must be enabled or I2C module won't work */ + REG(I2C_IE) = I2C_IE_SCD_IE | I2C_IE_XRDY_IE | + I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | I2C_IE_NACK_IE; + + /* Now enable I2C controller (get it out of reset) */ + REG(I2C_CON) = I2C_CON_EN; + + udelay(1000); +} + + +int i2c_probe(u_int8_t chip) +{ + int rc = 1; + + if (chip == REG(I2C_OA)) { + return(rc); + } + + REG(I2C_CON) = 0; + if (wait_for_bus()) {return(1);} + + /* try to read one byte from current (or only) address */ + REG(I2C_CNT) = 1; + REG(I2C_SA) = chip; + REG(I2C_CON) = (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP); + udelay (50000); + + if (!(REG(I2C_STAT) & I2C_STAT_NACK)) { + rc = 0; + flush_rx(); + REG(I2C_STAT) = 0xffff; + } else { + REG(I2C_STAT) = 0xffff; + REG(I2C_CON) |= I2C_CON_STP; + udelay(20000); + if (wait_for_bus()) {return(1);} + } + + flush_rx(); + REG(I2C_STAT) = 0xffff; + REG(I2C_CNT) = 0; + return(rc); +} + + +int i2c_read(u_int8_t chip, u_int32_t addr, int alen, u_int8_t *buf, int len) +{ + u_int32_t tmp; + int i; + + if ((alen < 0) || (alen > 2)) { + printf("%s(): bogus address length %x\n", __FUNCTION__, alen); + return(1); + } + + if (wait_for_bus()) {return(1);} + + if (alen != 0) { + /* Start address phase */ + tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX; + REG(I2C_CNT) = alen; + REG(I2C_SA) = chip; + REG(I2C_CON) = tmp; + + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK); + + CHECK_NACK(); + + switch (alen) { + case 2: + /* Send address MSByte */ + if (tmp & I2C_STAT_XRDY) { + REG(I2C_DXR) = (addr >> 8) & 0xff; + } else { + REG(I2C_CON) = 0; + return(1); + } + + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK); + + CHECK_NACK(); + /* No break, fall through */ + case 1: + /* Send address LSByte */ + if (tmp & I2C_STAT_XRDY) { + REG(I2C_DXR) = addr & 0xff; + } else { + REG(I2C_CON) = 0; + return(1); + } + + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK | I2C_STAT_ARDY); + + CHECK_NACK(); + + if (!(tmp & I2C_STAT_ARDY)) { + REG(I2C_CON) = 0; + return(1); + } + } + } + + /* Address phase is over, now read 'len' bytes and stop */ + tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP; + REG(I2C_CNT) = len & 0xffff; + REG(I2C_SA) = chip; + REG(I2C_CON) = tmp; + + for (i = 0; i < len; i++) { + tmp = poll_i2c_irq(I2C_STAT_RRDY | I2C_STAT_NACK | I2C_STAT_ROVR); + + CHECK_NACK(); + + if (tmp & I2C_STAT_RRDY) { + buf[i] = REG(I2C_DRR); + } else { + REG(I2C_CON) = 0; + return(1); + } + } + + tmp = poll_i2c_irq(I2C_STAT_SCD | I2C_STAT_NACK); + + CHECK_NACK(); + + if (!(tmp & I2C_STAT_SCD)) { + REG(I2C_CON) = 0; + return(1); + } + + flush_rx(); + REG(I2C_STAT) = 0xffff; + REG(I2C_CNT) = 0; + REG(I2C_CON) = 0; + + return(0); +} + + +int i2c_write(u_int8_t chip, u_int32_t addr, int alen, u_int8_t *buf, int len) +{ + u_int32_t tmp; + int i; + + if ((alen < 0) || (alen > 2)) { + printf("%s(): bogus address length %x\n", __FUNCTION__, alen); + return(1); + } + if (len < 0) { + printf("%s(): bogus length %x\n", __FUNCTION__, len); + return(1); + } + + if (wait_for_bus()) {return(1);} + + /* Start address phase */ + tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX | I2C_CON_STP; + REG(I2C_CNT) = (alen == 0) ? len & 0xffff : (len & 0xffff) + alen; + REG(I2C_SA) = chip; + REG(I2C_CON) = tmp; + + switch (alen) { + case 2: + /* Send address MSByte */ + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK); + + CHECK_NACK(); + + if (tmp & I2C_STAT_XRDY) { + REG(I2C_DXR) = (addr >> 8) & 0xff; + } else { + REG(I2C_CON) = 0; + return(1); + } + /* No break, fall through */ + case 1: + /* Send address LSByte */ + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK); + + CHECK_NACK(); + + if (tmp & I2C_STAT_XRDY) { + REG(I2C_DXR) = addr & 0xff; + } else { + REG(I2C_CON) = 0; + return(1); + } + } + + for (i = 0; i < len; i++) { + tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK); + + CHECK_NACK(); + + if (tmp & I2C_STAT_XRDY) { + REG(I2C_DXR) = buf[i]; + } else { + return(1); + } + } + + tmp = poll_i2c_irq(I2C_STAT_SCD | I2C_STAT_NACK); + + CHECK_NACK(); + + if (!(tmp & I2C_STAT_SCD)) { + REG(I2C_CON) = 0; + return(1); + } + + flush_rx(); + REG(I2C_STAT) = 0xffff; + REG(I2C_CNT) = 0; + REG(I2C_CON) = 0; + + return(0); +} |