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authorMike Turquette <mturquette@ti.com>2010-02-24 22:06:00 +0300
committerPaul Walmsley <paul@pwsan.com>2010-02-24 22:06:00 +0300
commita7e069fc5a560c096a2597d7be27f45fb4a01df7 (patch)
tree5171d2350215339101f9966ea17decbb1819d7f3 /arch/arm/mach-omap2/clock34xx.h
parentc23a97d377077c67e01f7526de3a411b316ee4f6 (diff)
downloadlinux-a7e069fc5a560c096a2597d7be27f45fb4a01df7.tar.xz
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.h3
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