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| author |   Weijie Gao <hackpascal@gmail.com> | 2016-03-17 06:34:09 +0300 |
|---|---|---|
| committer |   Ralf Baechle <ralf@linux-mips.org> | 2016-04-03 12:32:09 +0200 |
| commit | c338d59d12dc93c3287160acd7e726b56dc94f43 (patch) | |
| tree | f26c90d90253ebd00fac0d964b152f09a9bc2fba /arch | |
| parent | dt-bindings: clock: qca,ath79-pll: fix copy-paste typos (diff) | |
| download | linux-dev-c338d59d12dc93c3287160acd7e726b56dc94f43.tar.xz linux-dev-c338d59d12dc93c3287160acd7e726b56dc94f43.zip | |
MIPS: ath79: Fix the ar724x clock calculation
According to the AR7242 datasheet section 2.8, AR724X CPUs use a 40MHz
input clock as the REF_CLK instead of 5MHz.
The correct CPU PLL calculation procedure is as follows:
CPU_PLL = (FB * REF_CLK) / REF_DIV / 2.
This patch is compatible with the current calculation procedure with
default FB and REF_DIV values.
Tested on AR7240, AR7241 and AR7242.
Signed-off-by: Weijie Gao <hackpascal@gmail.com>
Signed-off-by: Alban Bedel <albeu@free.fr> (Fixed the commit log message)
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12870/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/ath79/clock.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/mips/ath79/clock.c b/arch/mips/ath79/clock.c index eb5117ced95a..ed2846578405 100644 --- a/arch/mips/ath79/clock.c +++ b/arch/mips/ath79/clock.c @@ -26,7 +26,7 @@ #include "common.h" #define AR71XX_BASE_FREQ 40000000 -#define AR724X_BASE_FREQ 5000000 +#define AR724X_BASE_FREQ 40000000 #define AR913X_BASE_FREQ 5000000 static struct clk *clks[3]; @@ -103,8 +103,8 @@ static void __init ar724x_clocks_init(void) div = ((pll >> AR724X_PLL_FB_SHIFT) & AR724X_PLL_FB_MASK); freq = div * ref_rate; - div = ((pll >> AR724X_PLL_REF_DIV_SHIFT) & AR724X_PLL_REF_DIV_MASK); - freq *= div; + div = ((pll >> AR724X_PLL_REF_DIV_SHIFT) & AR724X_PLL_REF_DIV_MASK) * 2; + freq /= div; cpu_rate = freq; |