If a bus busy is detected when intializing the driver, toggle 9 times the scl pin. Therefore enable the test mode of the controller, in which the scl, sda pins can be controlled manually.
Tested on the siemens boards pxm2, rut and dxr2.
Signed-off-by: Heiko Schocher hs@denx.de Cc: Tom Rini trini@ti.com Cc: Hannes Petermaier oe5hpm@oevsv.at Cc: Lubomir Popov lpopov@mm-sol.com Cc: Steve Sakoman steve@sakoman.com Cc: Sandeep Paulraj s-paulraj@ti.com Cc: Vincent Stehlé v-stehle@ti.com Cc: Samuel Egli samuel.egli@siemens.com --- drivers/i2c/omap24xx_i2c.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index a39b591..0f1e35c 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -153,11 +153,60 @@ static uint omap24_i2c_setspeed(struct i2c_adapter *adap, uint speed)
return 0; } + +static void omap24_i2c_deblock(struct i2c_adapter *adap) +{ + struct i2c *i2c_base = omap24_get_base(adap); + int i; + u16 systest; + u16 orgsystest; + + /* set test mode ST_EN = 1 */ + orgsystest = readw(&i2c_base->systest); + systest = orgsystest; + /* enable testmode */ + systest |= I2C_SYSTEST_ST_EN; + writew(systest, &i2c_base->systest); + systest &= ~I2C_SYSTEST_TMODE_MASK; + systest |= 3 << I2C_SYSTEST_TMODE_SHIFT; + writew(systest, &i2c_base->systest); + + /* set SCL, SDA = 1 */ + systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O; + writew(systest, &i2c_base->systest); + udelay(10); + + /* toggle scl 9 clocks */ + for (i = 0; i < 9; i++) { + /* SCL = 0 */ + systest &= ~I2C_SYSTEST_SCL_O; + writew(systest, &i2c_base->systest); + udelay(10); + /* SCL = 1 */ + systest |= I2C_SYSTEST_SCL_O; + writew(systest, &i2c_base->systest); + udelay(10); + } + + /* send stop */ + systest &= ~I2C_SYSTEST_SDA_O; + writew(systest, &i2c_base->systest); + udelay(10); + systest |= I2C_SYSTEST_SCL_O | I2C_SYSTEST_SDA_O; + writew(systest, &i2c_base->systest); + udelay(10); + + /* restore original mode */ + writew(orgsystest, &i2c_base->systest); +} + static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) { struct i2c *i2c_base = omap24_get_base(adap); int timeout = I2C_TIMEOUT; + int deblock = 1;
+retry: if (readw(&i2c_base->con) & I2C_CON_EN) { writew(0, &i2c_base->con); udelay(50000); @@ -194,6 +243,14 @@ static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) udelay(1000); flush_fifo(adap); writew(0xFFFF, &i2c_base->stat); + + /* Handle possible failed I2C state */ + if (wait_for_bb(adap)) + if (deblock == 1) { + omap24_i2c_deblock(adap); + deblock = 0; + goto retry; + } }
static void flush_fifo(struct i2c_adapter *adap)