ARM: OMAP4: clock: round_rate and recalc functions for DPLL_ABE

OMAP4 DPLL_ABE can enable a 4X multipler on top of the normal MN multipler
and divider. This is achieved by setting CM_CLKMODE_DPLL_ABE.DPLL_REGM4XEN
bit in CKGEN module of CM1. From the OMAP4 TRM:

Fdpll = Fref x 2 x (4 x M/(N+1)) in case REGM4XEN bit field is set (only
applicable to DPLL_ABE).

Add new round_rate() and recalc() functions for OMAP4, that check the
setting of REGM4XEN bit and handle this appropriately. The new functions
are a simple wrapper on top of the existing omap2_dpll_round_rate() and
omap2_dpll_get_rate() functions to handle the REGM4XEN bit.

The REGM4XEN bit is only implemented for the ABE DPLL on OMAP4 and so
only dpll_abe_ck uses omap4_dpll_regm4xen_round_rate() and
omap4_dpll_regm4xen_recalc() functions.

Signed-off-by: Mike Turquette <mturquette@ti.com>
Tested-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
[paul@pwsan.com: fixed attempt to return a negative from a fn returning
		 unsigned; pass along errors from omap2_dpll_round_rate();
		 added documentation; added Jon's S-o-b]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clock.h b/arch/arm/mach-omap2/clock.h
index 48ac568881bd..2311bc217226 100644
--- a/arch/arm/mach-omap2/clock.h
+++ b/arch/arm/mach-omap2/clock.h
@@ -66,6 +66,8 @@ void omap3_noncore_dpll_disable(struct clk *clk);
 int omap4_dpllmx_gatectrl_read(struct clk *clk);
 void omap4_dpllmx_allow_gatectrl(struct clk *clk);
 void omap4_dpllmx_deny_gatectrl(struct clk *clk);
+long omap4_dpll_regm4xen_round_rate(struct clk *clk, unsigned long target_rate);
+unsigned long omap4_dpll_regm4xen_recalc(struct clk *clk);
 
 #ifdef CONFIG_OMAP_RESET_CLOCKS
 void omap2_clk_disable_unused(struct clk *clk);