[ARM] OMAP2: Implement CPUfreq frequency table based on PRCM table

This patch adds a CPUfreq frequency-table implementation for OMAP2 by
walking the PRCM rate-table for available entries and adding them to a
CPUfreq table.

CPUfreq can then be used to manage switching between all the available
entries in the PRCM rate table.  Either use the CPUfreq sysfs
interface directly, (see Section 3 of Documentation/cpu-freq/user-guide.txt)
or use the cpufrequtils package:
http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufrequtils.html

Signed-off-by: Kevin Hilman <khilman@mvista.com>

Updated to try to use cpufreq_table if it exists.

linux-omap source commit is 77ce544fa48deb7a2003f454624e3ca10d37ab87.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 42 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c
index 421728a7f903..b9902666e4b7 100644
--- a/arch/arm/mach-omap2/clock24xx.c
+++ b/arch/arm/mach-omap2/clock24xx.c
@@ -574,6 +574,45 @@ static int omap2_select_table_rate(struct clk *clk, unsigned long rate)
         return 0;
 }
 
+#ifdef CONFIG_CPU_FREQ
+/*
+ * Walk PRCM rate table and fillout cpufreq freq_table
+ */
+static struct cpufreq_frequency_table freq_table[ARRAY_SIZE(rate_table)];
+
+void omap2_clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
+{
+        struct prcm_config *prcm;
+        int i = 0;
+
+        for (prcm = rate_table; prcm->mpu_speed; prcm++) {
+                if (!(prcm->flags & cpu_mask))
+                        continue;
+                if (prcm->xtal_speed != sys_ck.rate)
+                        continue;
+
+                /* don't put bypass rates in table */
+                if (prcm->dpll_speed == prcm->xtal_speed)
+                        continue;
+
+                freq_table[i].index = i;
+                freq_table[i].frequency = prcm->mpu_speed / 1000;
+                i++;
+        }
+
+        if (i == 0) {
+                printk(KERN_WARNING "%s: failed to initialize frequency "
+                       "table\n", __func__);
+                return;
+        }
+
+        freq_table[i].index = i;
+        freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+        *table = &freq_table[0];
+}
+#endif
+
 static struct clk_functions omap2_clk_functions = {
         .clk_enable             = omap2_clk_enable,
         .clk_disable            = omap2_clk_disable,
@@ -581,6 +620,9 @@ static struct clk_functions omap2_clk_functions = {
         .clk_set_rate           = omap2_clk_set_rate,
         .clk_set_parent         = omap2_clk_set_parent,
         .clk_disable_unused     = omap2_clk_disable_unused,
+#ifdef  CONFIG_CPU_FREQ
+        .clk_init_cpufreq_table = omap2_clk_init_cpufreq_table,
+#endif
 };
 
 static u32 omap2_get_apll_clkin(void)