avr32: Add gclk helper functions
Add two helper functions for configuring and enabling generic clocks:
- gclk_enable_output: Enables output on a GCLKx pin
- gclk_set_rate: Configures a gclk to run at a specific rate
This should eliminate any reason to go mucking about with PM registers
from board code.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/cpu/at32ap/at32ap700x/clk.c b/cpu/at32ap/at32ap700x/clk.c
index b3aa034..a6a6c88 100644
--- a/cpu/at32ap/at32ap700x/clk.c
+++ b/cpu/at32ap/at32ap700x/clk.c
@@ -25,6 +25,7 @@
#include <asm/arch/clk.h>
#include <asm/arch/memory-map.h>
+#include <asm/arch/portmux.h>
#include "sm.h"
@@ -66,3 +67,27 @@
sm_writel(PM_MCCTRL, SM_BIT(PLLSEL));
#endif
}
+
+unsigned long __gclk_set_rate(unsigned int id, enum gclk_parent parent,
+ unsigned long rate, unsigned long parent_rate)
+{
+ unsigned long divider;
+
+ if (rate == 0 || parent_rate == 0) {
+ sm_writel(PM_GCCTRL(id), 0);
+ return 0;
+ }
+
+ divider = (parent_rate + rate / 2) / rate;
+ if (divider <= 1) {
+ sm_writel(PM_GCCTRL(id), parent | SM_BIT(CEN));
+ rate = parent_rate;
+ } else {
+ divider = min(255, divider / 2 - 1);
+ sm_writel(PM_GCCTRL(id), parent | SM_BIT(CEN) | SM_BIT(DIVEN)
+ | SM_BF(DIV, divider));
+ rate = parent_rate / (2 * (divider + 1));
+ }
+
+ return rate;
+}