On 06/05/2012 01:06, Marek Vasut wrote:
Dear Troy Kisky,
On 5/5/2012 2:36 PM, Marek Vasut wrote:
Dear Troy Kisky,
On 5/5/2012 6:08 AM, Marek Vasut wrote:
Dear Troy Kisky,
On 4/24/2012 8:33 PM, Troy Kisky wrote: > Other then being very weird, this code was also wrong. > For example, say I set speed to 100K. I'll read back the speed > as 85937. But the speed is really 85937.5, so we I reset > the speed to 85937, I'll get 73660.7. After a couple of transactions > my speed is now exactly 68750 so it will remain there. > > Signed-off-by: Troy Kiskytroy.kisky@boundarydevices.com > --- > > drivers/i2c/mxc_i2c.c | 6 ------ > 1 files changed, 0 insertions(+), 6 deletions(-) > > diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c > index 416ffee..fc68062 100644 > --- a/drivers/i2c/mxc_i2c.c > +++ b/drivers/i2c/mxc_i2c.c > @@ -231,12 +231,6 @@ int i2c_imx_start(void) > > struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; > unsigned int temp = 0; > int result; > > - int speed = i2c_get_bus_speed(); > - u8 clk_idx = i2c_imx_get_clk(speed); > - u8 idx = i2c_clk_div[clk_idx][1]; > - > - /* Store divider value */ > - writeb(idx,&i2c_regs->ifdr); > > /* Enable I2C controller */ > writeb(0,&i2c_regs->i2sr);
Marek would you care to ack/nak this? It is deleting code that you added.
Ok, who will set the controller speed if you remove this?
i2c_init is the only function that writes the ifdr register after this patch.
And i2c_init() is called on every boot. Correct?
This is fine because this register is not affected by a software reset.
I take it you verified this or that you're sure here :)
I haven't looked at every reference manual, but if some oddball chip needs it reinitialized after a software reset, then the fix should go into the i2c_reset function, not i2c_imx_start. And this patch would not be introducing a regression for the oddball chip anyway.
Ok, everything was already clear, and I can also add my:
Acked-by: Stefano Babic sbabic@denx.de
Best regards, Stefano Babic