Hello Michael,
Thanks for posting your patches in plain text.
Michael Durrant wrote:
drivers_i2c_fsl_i2c.patch
- need to set I2C to be idle according to the MCF5282 user's manual
If I2SR[IBB] is set when the I2C bus module is enabled, execute the following code sequence before proceeding with normal initialization code. This issues a STOP command to the slave device, placing it in idle state as if it were just power-cycled on.
I2CR = 0x0 I2CR = 0xA dummy read of I2DR I2SR = 0x0 I2CR = 0x0
Signed-off-by: David Wu davidwu@arcturusnetworks.com Signed-off-by: Michael Durrant mdurrant@arcturusnetworks.com
drivers/i2c/fsl_i2c.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c index 2241990..bce750c 100644 --- a/drivers/i2c/fsl_i2c.c +++ b/drivers/i2c/fsl_i2c.c @@ -251,12 +251,25 @@ i2c_init(int speed, int slaveadd) #endif }
+static __inline__ int i2c_set_idle(void) +{
- writeb(0, &i2c_dev[i2c_bus_num]->cr);
- writeb(I2C_CR_MEN | I2C_CR_MSTA, &i2c_dev[i2c_bus_num]->cr);
- readb(&i2c_dev[i2c_bus_num]->dr);
- writeb(0, &i2c_dev[i2c_bus_num]->sr);
- writeb(0, &i2c_dev[i2c_bus_num]->cr);
- writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr);
+}
static int i2c_wait4bus(void) { unsigned long long timeval = get_ticks(); const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
- if (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB)
i2c_set_idle();- while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) { if ((get_ticks() - timeval) > timeout) return -1;
Hmm.. I can;t find this for example in the MPC8360ERM.pdf, which uses also this driver ... So I vote for activating this only, if this driver is used for __M68K__ ...
Also, you write, that this sequence is necessary before normal initialization code, but i2c_wait4bus() is called from i2c_read() and i2c_write(), so the I2C bus is long ago initialized ... or what do you mean with "normal initialization code" ?
Also, whats with multimaster systems? Your code maybe cuts a running data transmission. The MPC8360ERM.pdf manual says "check the MBB bit, if the bus is free, before switching to master mode", thats what actual code did ... so, I want this only activated, if __M68K__ is defined ...
bye Heiko