[ARM] omap: add support for bypassing DPLLs

This roughly corresponds with OMAP commits: 7d06c48, 3241b19,
88b5d9b, 18a5500, 9c909ac, 5c6497b, 8b1f0bd, 2ac1da8.

For both OMAP2 and OMAP3, we note the reference and bypass clocks in
the DPLL data structure.  Whenever we modify the DPLL rate, we first
ensure that both the reference and bypass clocks are enabled.  Then,
we decide whether to use the reference and DPLL, or the bypass clock
if the desired rate is identical to the bypass rate, and program the
DPLL appropriately.  Finally, we update the clock's parent, and then
disable the unused clocks.

This keeps the parents correctly balanced, and more importantly ensures
that the bypass clock is running whenever we reprogram the DPLL.  This
is especially important because the procedure for reprogramming the DPLL
involves switching to the bypass clock.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clock.h b/arch/arm/mach-omap2/clock.h
index ca6bf226859..2679ddfa642 100644
--- a/arch/arm/mach-omap2/clock.h
+++ b/arch/arm/mach-omap2/clock.h
@@ -21,6 +21,21 @@
 /* The maximum error between a target DPLL rate and the rounded rate in Hz */
 #define DEFAULT_DPLL_RATE_TOLERANCE	50000
 
+/* CM_CLKSEL2_PLL.CORE_CLK_SRC bits (2XXX) */
+#define CORE_CLK_SRC_32K		0x0
+#define CORE_CLK_SRC_DPLL		0x1
+#define CORE_CLK_SRC_DPLL_X2		0x2
+
+/* OMAP2xxx CM_CLKEN_PLL.EN_DPLL bits - for omap2_get_dpll_rate() */
+#define OMAP2XXX_EN_DPLL_LPBYPASS		0x1
+#define OMAP2XXX_EN_DPLL_FRBYPASS		0x2
+#define OMAP2XXX_EN_DPLL_LOCKED			0x3
+
+/* OMAP3xxx CM_CLKEN_PLL*.EN_*_DPLL bits - for omap2_get_dpll_rate() */
+#define OMAP3XXX_EN_DPLL_LPBYPASS		0x5
+#define OMAP3XXX_EN_DPLL_FRBYPASS		0x6
+#define OMAP3XXX_EN_DPLL_LOCKED			0x7
+
 int omap2_clk_init(void);
 int omap2_clk_enable(struct clk *clk);
 void omap2_clk_disable(struct clk *clk);