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| author | Mike Turquette <mturquette@ti.com> | 2010-02-24 20:06:00 +0100 |
|---|---|---|
| committer | Paul Walmsley <paul@pwsan.com> | 2010-02-24 20:06:00 +0100 |
| commit | a7e069fc5a560c096a2597d7be27f45fb4a01df7 (patch) | |
| tree | 5171d2350215339101f9966ea17decbb1819d7f3 /arch/arm/mach-omap2/clock34xx.h | |
| parent | OMAP: HWMOD: Add support for early device register into omap device layer (diff) | |
| download | linux-a7e069fc5a560c096a2597d7be27f45fb4a01df7.tar.xz linux-a7e069fc5a560c096a2597d7be27f45fb4a01df7.zip | |
OMAP3630: Clock: Workaround for DPLL HS divider limitation
This patch implements a workaround for the DPLL HS divider limitation
in OMAP3630 as given by Errata ID: i556.
Errata:
When PWRDN bit is set, it resets the internal HSDIVIDER divide-by value (Mx).
The reset value gets loaded instead of the previous value.
The following HSDIVIDERs exhibit above behavior:
. DPLL4 : M6 / M5 / M4 / M3 / M2 (CM_CLKEN_PLL[31:26] register bits)
. DPLL3 : M3 (CM_CLKEN_PLL[12] register bit).
Work Around:
It is mandatory to apply the following sequence to ensure the write
value will
be loaded in DPLL HSDIVIDER FSM:
The global sequence when using PWRDN bit is the following:
. Disable Mx HSDIVIDER clock output related functional clock enable bits
(in CM_FCLKEN_xxx / CM_ICLKEN_xxx)
. Enable PWRDN bit of HSDIVIDER
. Disable PWRDN bit of HSDIVIDER
. Read current HSDIVIDER register value
. Write different value in HSDIVIDER register
. Write expected value in HSDIVIDER register
. Enable Mx HSDIVIDER clock output related functional clocks
(CM_FCLKEN_xxx / CM_ICLKEN_xxx)
Signed-off-by: Mike Turquette <mturquette@ti.com>
Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Vijaykumar GN <vijaykumar.gn@ti.com>
[paul@pwsan.com: updated patch to apply; made workaround function static;
marked as being 36xx-specific]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Diffstat (limited to 'arch/arm/mach-omap2/clock34xx.h')
| -rw-r--r-- | arch/arm/mach-omap2/clock34xx.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/clock34xx.h b/arch/arm/mach-omap2/clock34xx.h index bc1051578e81..720091ddced1 100644 --- a/arch/arm/mach-omap2/clock34xx.h +++ b/arch/arm/mach-omap2/clock34xx.h @@ -26,4 +26,7 @@ extern const struct clkops omap3_clkops_noncore_dpll_ops; extern const struct clkops clkops_am35xx_ipss_module_wait; extern const struct clkops clkops_am35xx_ipss_wait; +/* OMAP36xx-specific clkops */ +extern const struct clkops clkops_omap36xx_pwrdn_with_hsdiv_wait_restore; + #endif |