i2c: omap: fix bus recovery setup
At least on the AM335x, enabling OMAP_I2C_SYSTEST_ST_EN is not enough to allow direct access to the SCL and SDA pins. In addition to ST_EN, we need to set the TMODE to 0b11 (Loop back & SDA/SCL IO mode select). Also, as the reset values of SCL_O and SDA_O are 0 (which means "drive low level"), we need to set them to 1 (which means "high-impedance") to avoid unwanted changes on the pins. As a precaution, reset all these bits to their default values after recovery is complete. Signed-off-by: Jan Luebbe <jlu@pengutronix.de> Tested-by: Alexander Sverdlin <alexander.sverdlin@gmail.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
parent
8b06260836
commit
828e66c0ed
|
@ -1247,7 +1247,14 @@ static void omap_i2c_prepare_recovery(struct i2c_adapter *adap)
|
|||
u32 reg;
|
||||
|
||||
reg = omap_i2c_read_reg(dev, OMAP_I2C_SYSTEST_REG);
|
||||
/* enable test mode */
|
||||
reg |= OMAP_I2C_SYSTEST_ST_EN;
|
||||
/* select SDA/SCL IO mode */
|
||||
reg |= 3 << OMAP_I2C_SYSTEST_TMODE_SHIFT;
|
||||
/* set SCL to high-impedance state (reset value is 0) */
|
||||
reg |= OMAP_I2C_SYSTEST_SCL_O;
|
||||
/* set SDA to high-impedance state (reset value is 0) */
|
||||
reg |= OMAP_I2C_SYSTEST_SDA_O;
|
||||
omap_i2c_write_reg(dev, OMAP_I2C_SYSTEST_REG, reg);
|
||||
}
|
||||
|
||||
|
@ -1257,7 +1264,11 @@ static void omap_i2c_unprepare_recovery(struct i2c_adapter *adap)
|
|||
u32 reg;
|
||||
|
||||
reg = omap_i2c_read_reg(dev, OMAP_I2C_SYSTEST_REG);
|
||||
/* restore reset values */
|
||||
reg &= ~OMAP_I2C_SYSTEST_ST_EN;
|
||||
reg &= ~OMAP_I2C_SYSTEST_TMODE_MASK;
|
||||
reg &= ~OMAP_I2C_SYSTEST_SCL_O;
|
||||
reg &= ~OMAP_I2C_SYSTEST_SDA_O;
|
||||
omap_i2c_write_reg(dev, OMAP_I2C_SYSTEST_REG, reg);
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue