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.
Agreed, I think I already acked this, sorry for the delay :)
Troy
Best regards, Marek Vasut