From: mattias@vmlinux.org (Mattias Walstrom)
To: linux-arm-kernel@lists.infradead.org
Subject: imx27: I2C clock frequency
Date: Tue, 09 Nov 2010 20:37:12 +0100 [thread overview]
Message-ID: <4CD9A2E8.2040002@vmlinux.org> (raw)
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
reply other threads:[~2010-11-09 19:37 UTC|newest]
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