All of lore.kernel.org
 help / color / mirror / Atom feed
* imx27: I2C clock frequency
@ 2010-11-09 19:37 Mattias Walstrom
  0 siblings, 0 replies; only message in thread
From: Mattias Walstrom @ 2010-11-09 19:37 UTC (permalink / raw)
  To: linux-arm-kernel

Hi!
When investigating the i2c clock frequency on our custom imx27-board (running 2.6.32) we discovered that it was not correct, instead of 100khz we got 40khz. When looking at the code we noticed a possible problem with get_rate_ipg. With the following patch we get an i2c clock at 100khz (as expected).

Is this the right way to solve the problem? I am unsure if I can use the AHB divider directly for the ipgclock-rate.

--- linux-2.6.32.23.orig/arch/arm/mach-mx2/clock_imx27.c
+++ linux-2.6.32.23/arch/arm/mach-mx2/clock_imx27.c
@@ -401,7 +401,7 @@ static unsigned long get_rate_ipg(struct
 	unsigned long rate, ipg_pdf;
 
 	if (mx27_revision() >= CHIP_REV_2_0)
-		return clk_get_rate(clk->parent);
+		ipg_pdf = (__raw_readl(CCM_CSCR) >> 8) & 3;
 	else
 		ipg_pdf = (__raw_readl(CCM_CSCR) >> 8) & 1;

Best regards

Mattias Walstr?m

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2010-11-09 19:37 UTC | newest]

Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-11-09 19:37 imx27: I2C clock frequency Mattias Walstrom

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.