From 4dd39bb12f5b9f0d9a98f29071dc1c51e9306954 Mon Sep 17 00:00:00 2001 From: Sonic Zhang Date: Tue, 22 Apr 2008 22:16:47 +0200 Subject: [PATCH] i2c-bfin-twi: Add repeat start feature to avoid break of a bundle of i2c master xfer operation - Create a new mode TWI_I2C_MODE_REPEAT. - No change to smbus operation. Signed-off-by: Sonic Zhang Signed-off-by: Bryan Wu Signed-off-by: Jean Delvare --- drivers/i2c/busses/i2c-bfin-twi.c | 185 ++++++++++++++++++------------ 1 file changed, 114 insertions(+), 71 deletions(-) diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 7dbdaeb707a..86956a8f0ae 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -39,9 +39,10 @@ #define POLL_TIMEOUT (2 * HZ) /* SMBus mode*/ -#define TWI_I2C_MODE_STANDARD 0x01 -#define TWI_I2C_MODE_STANDARDSUB 0x02 -#define TWI_I2C_MODE_COMBINED 0x04 +#define TWI_I2C_MODE_STANDARD 1 +#define TWI_I2C_MODE_STANDARDSUB 2 +#define TWI_I2C_MODE_COMBINED 3 +#define TWI_I2C_MODE_REPEAT 4 struct bfin_twi_iface { int irq; @@ -58,6 +59,9 @@ struct bfin_twi_iface { struct timer_list timeout_timer; struct i2c_adapter adap; struct completion complete; + struct i2c_msg *pmsg; + int msg_num; + int cur_msg; }; static struct bfin_twi_iface twi_iface; @@ -76,12 +80,16 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) /* start receive immediately after complete sending in * combine mode. */ - else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) { + else if (iface->cur_mode == TWI_I2C_MODE_COMBINED) bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MDIR | RSTART); - } else if (iface->manual_stop) + else if (iface->manual_stop) bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | STOP); + else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && + iface->cur_msg+1 < iface->msg_num) + bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() + | RSTART); SSYNC(); /* Clear status */ bfin_write_TWI_INT_STAT(XMTSERV); @@ -108,6 +116,11 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | STOP); SSYNC(); + } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && + iface->cur_msg+1 < iface->msg_num) { + bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() + | RSTART); + SSYNC(); } /* Clear interrupt source */ bfin_write_TWI_INT_STAT(RCVSERV); @@ -119,7 +132,7 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) bfin_write_TWI_MASTER_STAT(0x3e); bfin_write_TWI_MASTER_CTL(0); SSYNC(); - iface->result = -1; + iface->result = -EIO; /* if both err and complete int stats are set, return proper * results. */ @@ -170,6 +183,42 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface) bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN | MDIR); SSYNC(); + } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && + iface->cur_msg+1 < iface->msg_num) { + iface->cur_msg++; + iface->transPtr = iface->pmsg[iface->cur_msg].buf; + iface->writeNum = iface->readNum = + iface->pmsg[iface->cur_msg].len; + /* Set Transmit device address */ + bfin_write_TWI_MASTER_ADDR( + iface->pmsg[iface->cur_msg].addr); + if (iface->pmsg[iface->cur_msg].flags & I2C_M_RD) + iface->read_write = I2C_SMBUS_READ; + else { + iface->read_write = I2C_SMBUS_WRITE; + /* Transmit first data */ + if (iface->writeNum > 0) { + bfin_write_TWI_XMT_DATA8( + *(iface->transPtr++)); + iface->writeNum--; + SSYNC(); + } + } + + if (iface->pmsg[iface->cur_msg].len <= 255) + bfin_write_TWI_MASTER_CTL( + iface->pmsg[iface->cur_msg].len << 6); + else { + bfin_write_TWI_MASTER_CTL(0xff << 6); + iface->manual_stop = 1; + } + /* remove restart bit and enable master receive */ + bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() & + ~RSTART); + bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | + MEN | ((iface->read_write == I2C_SMBUS_READ) ? + MDIR : 0)); + SSYNC(); } else { iface->result = 1; bfin_write_TWI_INT_MASK(0); @@ -221,7 +270,6 @@ static int bfin_twi_master_xfer(struct i2c_adapter *adap, { struct bfin_twi_iface *iface = adap->algo_data; struct i2c_msg *pmsg; - int i, ret; int rc = 0; if (!(bfin_read_TWI_CONTROL() & TWI_ENA)) @@ -231,81 +279,76 @@ static int bfin_twi_master_xfer(struct i2c_adapter *adap, yield(); } - ret = 0; - for (i = 0; rc >= 0 && i < num; i++) { - pmsg = &msgs[i]; - if (pmsg->flags & I2C_M_TEN) { - dev_err(&(adap->dev), "i2c-bfin-twi: 10 bits addr " - "not supported !\n"); - rc = -EINVAL; - break; - } + iface->pmsg = msgs; + iface->msg_num = num; + iface->cur_msg = 0; - iface->cur_mode = TWI_I2C_MODE_STANDARD; - iface->manual_stop = 0; - iface->transPtr = pmsg->buf; - iface->writeNum = iface->readNum = pmsg->len; - iface->result = 0; - iface->timeout_count = 10; - /* Set Transmit device address */ - bfin_write_TWI_MASTER_ADDR(pmsg->addr); - - /* FIFO Initiation. Data in FIFO should be - * discarded before start a new operation. - */ - bfin_write_TWI_FIFO_CTL(0x3); - SSYNC(); - bfin_write_TWI_FIFO_CTL(0); - SSYNC(); + pmsg = &msgs[0]; + if (pmsg->flags & I2C_M_TEN) { + dev_err(&adap->dev, "10 bits addr not supported!\n"); + return -EINVAL; + } - if (pmsg->flags & I2C_M_RD) - iface->read_write = I2C_SMBUS_READ; - else { - iface->read_write = I2C_SMBUS_WRITE; - /* Transmit first data */ - if (iface->writeNum > 0) { - bfin_write_TWI_XMT_DATA8(*(iface->transPtr++)); - iface->writeNum--; - SSYNC(); - } + iface->cur_mode = TWI_I2C_MODE_REPEAT; + iface->manual_stop = 0; + iface->transPtr = pmsg->buf; + iface->writeNum = iface->readNum = pmsg->len; + iface->result = 0; + iface->timeout_count = 10; + /* Set Transmit device address */ + bfin_write_TWI_MASTER_ADDR(pmsg->addr); + + /* FIFO Initiation. Data in FIFO should be + * discarded before start a new operation. + */ + bfin_write_TWI_FIFO_CTL(0x3); + SSYNC(); + bfin_write_TWI_FIFO_CTL(0); + SSYNC(); + + if (pmsg->flags & I2C_M_RD) + iface->read_write = I2C_SMBUS_READ; + else { + iface->read_write = I2C_SMBUS_WRITE; + /* Transmit first data */ + if (iface->writeNum > 0) { + bfin_write_TWI_XMT_DATA8(*(iface->transPtr++)); + iface->writeNum--; + SSYNC(); } + } - /* clear int stat */ - bfin_write_TWI_INT_STAT(MERR|MCOMP|XMTSERV|RCVSERV); + /* clear int stat */ + bfin_write_TWI_INT_STAT(MERR | MCOMP | XMTSERV | RCVSERV); - /* Interrupt mask . Enable XMT, RCV interrupt */ - bfin_write_TWI_INT_MASK(MCOMP | MERR | - ((iface->read_write == I2C_SMBUS_READ)? - RCVSERV : XMTSERV)); - SSYNC(); + /* Interrupt mask . Enable XMT, RCV interrupt */ + bfin_write_TWI_INT_MASK(MCOMP | MERR | RCVSERV | XMTSERV); + SSYNC(); - if (pmsg->len > 0 && pmsg->len <= 255) - bfin_write_TWI_MASTER_CTL(pmsg->len << 6); - else if (pmsg->len > 255) { - bfin_write_TWI_MASTER_CTL(0xff << 6); - iface->manual_stop = 1; - } else - break; + if (pmsg->len <= 255) + bfin_write_TWI_MASTER_CTL(pmsg->len << 6); + else { + bfin_write_TWI_MASTER_CTL(0xff << 6); + iface->manual_stop = 1; + } - iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; - add_timer(&iface->timeout_timer); + iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; + add_timer(&iface->timeout_timer); - /* Master enable */ - bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN | - ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) | - ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ>100) ? FAST : 0)); - SSYNC(); + /* Master enable */ + bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN | + ((iface->read_write == I2C_SMBUS_READ) ? MDIR : 0) | + ((CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ > 100) ? FAST : 0)); + SSYNC(); - wait_for_completion(&iface->complete); + wait_for_completion(&iface->complete); - rc = iface->result; - if (rc == 1) - ret++; - else if (rc == -1) - break; - } + rc = iface->result; - return ret; + if (rc == 1) + return num; + else + return rc; } /* -- 2.20.1