diff options
| author | Moiz Sonasath | 2010-02-16 18:57:21 -0600 |
|---|---|---|
| committer | Samuel Ortiz | 2010-03-07 22:17:23 +0100 |
| commit | a29aaf55cd6faa75e35abfe00bd3ffc537490485 (patch) | |
| tree | 8f883a25bb154df5bff43a3980752a973da99a10 /include/linux/i2c | |
| parent | e82c60ae7d3a7f19c4b9b3e7bd6ea298fa5efe93 (diff) | |
mfd: Disable TWL4030/5030 I2C1/I2C4 internal pull-ups
This patch disables TWL4030/5030 I2C1 adn I2C4(SR) internal pull-up, to
use only the external HW resistor >=470 Ohm for the assured
functionality in HS mode.
While testing the I2C in High Speed mode, it was discovered that
without a proper pull-up resistor, there is data corruption during
multi-byte transfer. RTC(time_set) test case was used for testing.
From the analysis done, it was concluded that ideally we need a
pull-up of 1.6k Ohm(recomended) or atleast 470 Ohm or greater for
assured performance in HS mode.
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Allen Pais <allen.pais@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'include/linux/i2c')
| -rw-r--r-- | include/linux/i2c/twl.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h index 9733e9e53f2b..e28d4c0e45bd 100644 --- a/include/linux/i2c/twl.h +++ b/include/linux/i2c/twl.h @@ -239,6 +239,21 @@ int twl6030_interrupt_mask(u8 bit_mask, u8 offset); /*----------------------------------------------------------------------*/ +/*Interface Bit Register (INTBR) offsets + *(Use TWL_4030_MODULE_INTBR) + */ + +#define REG_GPPUPDCTR1 0x0F + +/*I2C1 and I2C4(SR) SDA/SCL pull-up control bits */ + +#define I2C_SCL_CTRL_PU BIT(0) +#define I2C_SDA_CTRL_PU BIT(2) +#define SR_I2C_SCL_CTRL_PU BIT(4) +#define SR_I2C_SDA_CTRL_PU BIT(6) + +/*----------------------------------------------------------------------*/ + /* * Keypad register offsets (use TWL4030_MODULE_KEYPAD) * ... SIH/interrupt only |