diff options
| -rw-r--r-- | src/i830_i2c.c | 52 |
1 files changed, 30 insertions, 22 deletions
diff --git a/src/i830_i2c.c b/src/i830_i2c.c index 973ca615..d246c167 100644 --- a/src/i830_i2c.c +++ b/src/i830_i2c.c @@ -261,24 +261,46 @@ I830I2CAddress(I2CDevPtr d, I2CSlaveAddr addr) #else +#define I2C_DEBUG 0 + +#if I2C_DEBUG +static Bool first = TRUE; +#endif + static void i830I2CGetBits(I2CBusPtr b, int *clock, int *data) { ScrnInfoPtr pScrn = xf86Screens[b->scrnIndex]; I830Ptr pI830 = I830PTR(pScrn); - CARD32 val; + CARD32 val, tristate = 0; val = INREG(b->DriverPrivate.uval); + + /* If we've released either of the lines from holding low, tristate them + * so that we can successfully read. Some hardware fails to read low + * values driven by slaves when our master is not tri-stated, while other + * chips succeed. + */ + if ((val & GPIO_DATA_DIR_OUT) && (val & GPIO_DATA_VAL_OUT)) + tristate |= GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK; + if ((val & GPIO_CLOCK_DIR_OUT) && (val & GPIO_CLOCK_VAL_OUT)) + tristate |= GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK; + + if (tristate) { + OUTREG(b->DriverPrivate.uval, tristate); + + val = INREG(b->DriverPrivate.uval); + } + *data = (val & GPIO_DATA_VAL_IN) != 0; *clock = (val & GPIO_CLOCK_VAL_IN) != 0; -} - -#define I2C_DEBUG 0 #if I2C_DEBUG -static int last_clock = 0, last_data = 0; -static Bool first = TRUE; + ErrorF("Getting I2C: %c %c\n", + *clock ? '^' : 'v', + *data ? '^' : 'v'); #endif +} static void i830I2CPutBits(I2CBusPtr b, int clock, int data) @@ -287,23 +309,12 @@ i830I2CPutBits(I2CBusPtr b, int clock, int data) #if I2C_DEBUG int cur_clock, cur_data; - char *debug = ""; #endif ScrnInfoPtr pScrn = xf86Screens[b->scrnIndex]; I830Ptr pI830 = I830PTR(pScrn); #if I2C_DEBUG - if (!first && cur_clock != last_clock && cur_data != last_data) { - /* If we change the clock and data simultaneously, that would be bad. - * I thought we did sometimes, but maybe not. - */ - debug = " <--"; - } - - last_clock = cur_clock; - last_data = cur_data; - i830I2CGetBits(b, &cur_clock, &cur_data); if (first) { @@ -311,13 +322,10 @@ i830I2CPutBits(I2CBusPtr b, int clock, int data) first = FALSE; } - ErrorF("Setting I2C 0x%08x to: %c %c (at: %c %c)%s\n", + ErrorF("Setting I2C 0x%08x to: %c %c\n", (int)b->DriverPrivate.uval, clock ? '^' : 'v', - data ? '^' : 'v', - cur_clock ? '^' : 'v', - cur_data ? '^' : 'v', - debug); + data ? '^' : 'v'); #endif if (!IS_I830(pI830) && !IS_845G(pI830)) { |