diff options
| -rw-r--r-- | drivers/i2c/omap24xx_i2c.c | 209 |
1 files changed, 117 insertions, 92 deletions
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index 3febd1f..a72d1a1 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -27,7 +27,7 @@ #include "omap24xx_i2c.h" -#define I2C_TIMEOUT 10 +#define I2C_TIMEOUT 1000 static void wait_for_bb (void); static u16 wait_for_pin (void); @@ -159,58 +159,56 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) /* no stop bit needed here */ writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, &i2c_base->con); - status = wait_for_pin (); - - if (status & I2C_STAT_XRDY) { - /* Important: have to use byte access */ - writeb (regoffset, &i2c_base->data); - udelay (20000); - if (readw (&i2c_base->stat) & I2C_STAT_NACK) { + /* send register offset */ + while (1) { + status = wait_for_pin(); + if (status == 0 || status & I2C_STAT_NACK) { i2c_error = 1; + goto read_exit; + } + if (status & I2C_STAT_XRDY) { + /* Important: have to use byte access */ + writeb(regoffset, &i2c_base->data); + writew(I2C_STAT_XRDY, &i2c_base->stat); + } + if (status & I2C_STAT_ARDY) { + writew(I2C_STAT_ARDY, &i2c_base->stat); + break; } - } else { - i2c_error = 1; } - if (!i2c_error) { - writew (I2C_CON_EN, &i2c_base->con); - while (readw(&i2c_base->stat) & - (I2C_STAT_XRDY | I2C_STAT_ARDY)) { - udelay (10000); - /* Have to clear pending interrupt to clear I2C_STAT */ - writew (0xFFFF, &i2c_base->stat); + /* set slave address */ + writew(devaddr, &i2c_base->sa); + /* read one byte from slave */ + writew(1, &i2c_base->cnt); + /* need stop bit here */ + writew(I2C_CON_EN | I2C_CON_MST | + I2C_CON_STT | I2C_CON_STP, + &i2c_base->con); + + /* receive data */ + while (1) { + status = wait_for_pin(); + if (status == 0 || status & I2C_STAT_NACK) { + i2c_error = 1; + goto read_exit; } - - /* set slave address */ - writew (devaddr, &i2c_base->sa); - /* read one byte from slave */ - writew (1, &i2c_base->cnt); - /* need stop bit here */ - writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, - &i2c_base->con); - - status = wait_for_pin (); if (status & I2C_STAT_RRDY) { #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \ defined(CONFIG_OMAP44XX) - *value = readb (&i2c_base->data); + *value = readb(&i2c_base->data); #else - *value = readw (&i2c_base->data); + *value = readw(&i2c_base->data); #endif - udelay (20000); - } else { - i2c_error = 1; + writew(I2C_STAT_RRDY, &i2c_base->stat); } - - if (!i2c_error) { - writew (I2C_CON_EN, &i2c_base->con); - while (readw (&i2c_base->stat) & - (I2C_STAT_RRDY | I2C_STAT_ARDY)) { - udelay (10000); - writew (0xFFFF, &i2c_base->stat); - } + if (status & I2C_STAT_ARDY) { + writew(I2C_STAT_ARDY, &i2c_base->stat); + break; } } + +read_exit: flush_fifo(); writew (0xFFFF, &i2c_base->stat); writew (0, &i2c_base->cnt); @@ -220,7 +218,7 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value) static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value) { int i2c_error = 0; - u16 status, stat; + u16 status; /* wait until bus not busy */ wait_for_bb (); @@ -233,49 +231,55 @@ static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value) writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX | I2C_CON_STP, &i2c_base->con); - /* wait until state change */ - status = wait_for_pin (); - - if (status & I2C_STAT_XRDY) { -#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \ - defined(CONFIG_OMAP44XX) - /* send out 1 byte */ - writeb (regoffset, &i2c_base->data); - writew (I2C_STAT_XRDY, &i2c_base->stat); - - status = wait_for_pin (); - if ((status & I2C_STAT_XRDY)) { - /* send out next 1 byte */ - writeb (value, &i2c_base->data); - writew (I2C_STAT_XRDY, &i2c_base->stat); - } else { + while (1) { + status = wait_for_pin(); + if (status == 0 || status & I2C_STAT_NACK) { i2c_error = 1; + goto write_exit; } + if (status & I2C_STAT_XRDY) { +#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \ + defined(CONFIG_OMAP44XX) + /* send register offset */ + writeb(regoffset, &i2c_base->data); + writew(I2C_STAT_XRDY, &i2c_base->stat); + + while (1) { + status = wait_for_pin(); + if (status == 0 || status & I2C_STAT_NACK) { + i2c_error = 1; + goto write_exit; + } + if (status & I2C_STAT_XRDY) { + /* send data */ + writeb(value, &i2c_base->data); + writew(I2C_STAT_XRDY, &i2c_base->stat); + } + if (status & I2C_STAT_ARDY) { + writew(I2C_STAT_ARDY, &i2c_base->stat); + break; + } + } + break; #else - /* send out two bytes */ - writew ((value << 8) + regoffset, &i2c_base->data); + /* send out two bytes */ + writew((value << 8) + regoffset, &i2c_base->data); + writew(I2C_STAT_XRDY, &i2c_base->stat); #endif - /* must have enough delay to allow BB bit to go low */ - udelay (50000); - if (readw (&i2c_base->stat) & I2C_STAT_NACK) { - i2c_error = 1; } - } else { - i2c_error = 1; + if (status & I2C_STAT_ARDY) { + writew(I2C_STAT_ARDY, &i2c_base->stat); + break; + } } - if (!i2c_error) { - int eout = 200; + wait_for_bb(); - writew (I2C_CON_EN, &i2c_base->con); - while ((stat = readw (&i2c_base->stat)) || (readw (&i2c_base->con) & I2C_CON_MST)) { - udelay (1000); - /* have to read to clear intrrupt */ - writew (0xFFFF, &i2c_base->stat); - if(--eout == 0) /* better leave with error than hang */ - break; - } - } + status = readw(&i2c_base->stat); + if (status & I2C_STAT_NACK) + i2c_error = 1; + +write_exit: flush_fifo(); writew (0xFFFF, &i2c_base->stat); writew (0, &i2c_base->cnt); @@ -306,6 +310,7 @@ static void flush_fifo(void) int i2c_probe (uchar chip) { + u16 status; int res = 1; /* default = fail */ if (chip == readw (&i2c_base->oa)) { @@ -321,19 +326,37 @@ int i2c_probe (uchar chip) writew (chip, &i2c_base->sa); /* stop bit needed here */ writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, &i2c_base->con); - /* enough delay for the NACK bit set */ - udelay (50000); - if (!(readw (&i2c_base->stat) & I2C_STAT_NACK)) { - res = 0; /* success case */ - flush_fifo(); - writew(0xFFFF, &i2c_base->stat); - } else { - writew(0xFFFF, &i2c_base->stat); /* failue, clear sources*/ - writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con); /* finish up xfer */ - udelay(20000); - wait_for_bb (); + while (1) { + status = wait_for_pin(); + if (status == 0) { + res = 1; + goto probe_exit; + } + if (status & I2C_STAT_NACK) { + res = 1; + writew(0xff, &i2c_base->stat); + writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con); + wait_for_bb (); + break; + } + if (status & I2C_STAT_ARDY) { + writew(I2C_STAT_ARDY, &i2c_base->stat); + break; + } + if (status & I2C_STAT_RRDY) { + res = 0; +#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \ + defined(CONFIG_OMAP44XX) + readb(&i2c_base->data); +#else + readw(&i2c_base->data); +#endif + writew(I2C_STAT_RRDY, &i2c_base->stat); + } } + +probe_exit: flush_fifo(); writew (0, &i2c_base->cnt); /* don't allow any more data in...we don't want it.*/ writew(0xFFFF, &i2c_base->stat); @@ -392,13 +415,13 @@ int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len) static void wait_for_bb (void) { - int timeout = 10; + int timeout = I2C_TIMEOUT; u16 stat; writew(0xFFFF, &i2c_base->stat); /* clear current interruts...*/ while ((stat = readw (&i2c_base->stat) & I2C_STAT_BB) && timeout--) { writew (stat, &i2c_base->stat); - udelay (50000); + udelay(1000); } if (timeout <= 0) { @@ -411,7 +434,7 @@ static void wait_for_bb (void) static u16 wait_for_pin (void) { u16 status; - int timeout = 10; + int timeout = I2C_TIMEOUT; do { udelay (1000); @@ -424,8 +447,10 @@ static u16 wait_for_pin (void) if (timeout <= 0) { printf ("timed out in wait_for_pin: I2C_STAT=%x\n", readw (&i2c_base->stat)); - writew(0xFFFF, &i2c_base->stat); -} + writew(0xFFFF, &i2c_base->stat); + status = 0; + } + return status; } |