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Diffstat (limited to 'arch/arm/mach-omap2/dpll44xx.c')
-rw-r--r--arch/arm/mach-omap2/dpll44xx.c64
1 files changed, 55 insertions, 9 deletions
diff --git a/arch/arm/mach-omap2/dpll44xx.c b/arch/arm/mach-omap2/dpll44xx.c
index d3326c474fdc..d28b0f726715 100644
--- a/arch/arm/mach-omap2/dpll44xx.c
+++ b/arch/arm/mach-omap2/dpll44xx.c
@@ -20,6 +20,15 @@
#include "clock44xx.h"
#include "cm-regbits-44xx.h"
+/*
+ * Maximum DPLL input frequency (FINT) and output frequency (FOUT) that
+ * can supported when using the DPLL low-power mode. Frequencies are
+ * defined in OMAP4430/60 Public TRM section 3.6.3.3.2 "Enable Control,
+ * Status, and Low-Power Operation Mode".
+ */
+#define OMAP4_DPLL_LP_FINT_MAX 1000000
+#define OMAP4_DPLL_LP_FOUT_MAX 100000000
+
/* Supported only on OMAP4 */
int omap4_dpllmx_gatectrl_read(struct clk_hw_omap *clk)
{
@@ -82,6 +91,31 @@ const struct clk_hw_omap_ops clkhwops_omap4_dpllmx = {
};
/**
+ * omap4_dpll_lpmode_recalc - compute DPLL low-power setting
+ * @dd: pointer to the dpll data structure
+ *
+ * Calculates if low-power mode can be enabled based upon the last
+ * multiplier and divider values calculated. If low-power mode can be
+ * enabled, then the bit to enable low-power mode is stored in the
+ * last_rounded_lpmode variable. This implementation is based upon the
+ * criteria for enabling low-power mode as described in the OMAP4430/60
+ * Public TRM section 3.6.3.3.2 "Enable Control, Status, and Low-Power
+ * Operation Mode".
+ */
+static void omap4_dpll_lpmode_recalc(struct dpll_data *dd)
+{
+ long fint, fout;
+
+ fint = __clk_get_rate(dd->clk_ref) / (dd->last_rounded_n + 1);
+ fout = fint * dd->last_rounded_m;
+
+ if ((fint < OMAP4_DPLL_LP_FINT_MAX) && (fout < OMAP4_DPLL_LP_FOUT_MAX))
+ dd->last_rounded_lpmode = 1;
+ else
+ dd->last_rounded_lpmode = 0;
+}
+
+/**
* omap4_dpll_regm4xen_recalc - compute DPLL rate, considering REGM4XEN bit
* @clk: struct clk * of the DPLL to compute the rate for
*
@@ -130,7 +164,6 @@ long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
unsigned long *parent_rate)
{
struct clk_hw_omap *clk = to_clk_hw_omap(hw);
- u32 v;
struct dpll_data *dd;
long r;
@@ -139,18 +172,31 @@ long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
dd = clk->dpll_data;
- /* regm4xen adds a multiplier of 4 to DPLL calculations */
- v = __raw_readl(dd->control_reg) & OMAP4430_DPLL_REGM4XEN_MASK;
-
- if (v)
- target_rate = target_rate / OMAP4430_REGM4XEN_MULT;
+ dd->last_rounded_m4xen = 0;
+ /*
+ * First try to compute the DPLL configuration for
+ * target rate without using the 4X multiplier.
+ */
r = omap2_dpll_round_rate(hw, target_rate, NULL);
+ if (r != ~0)
+ goto out;
+
+ /*
+ * If we did not find a valid DPLL configuration, try again, but
+ * this time see if using the 4X multiplier can help. Enabling the
+ * 4X multiplier is equivalent to dividing the target rate by 4.
+ */
+ r = omap2_dpll_round_rate(hw, target_rate / OMAP4430_REGM4XEN_MULT,
+ NULL);
if (r == ~0)
return r;
- if (v)
- clk->dpll_data->last_rounded_rate *= OMAP4430_REGM4XEN_MULT;
+ dd->last_rounded_rate *= OMAP4430_REGM4XEN_MULT;
+ dd->last_rounded_m4xen = 1;
+
+out:
+ omap4_dpll_lpmode_recalc(dd);
- return clk->dpll_data->last_rounded_rate;
+ return dd->last_rounded_rate;
}