[AVR32] Change system timer from count-compare to Timer/Counter 0

Due to limitation of the count-compare system timer (not able to
count when CPU is in sleep), the system timer had to be changed to
use a peripheral timer/counter.

The old COUNT-COMPARE code is still present in time.c as weak
functions. The new timer is added to the architecture directory.

This patch sets up TC0 as system timer The new timer has been tested
on AT32AP7000/ATSTK1000 at 100 Hz, 250 Hz, 300 Hz and 1000 Hz.

For more details about the timer/counter see the datasheet for
AT32AP700x available at

http://www.atmel.com/dyn/products/product_card.asp?part_id=3903

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/avr32/mach-at32ap/at32ap7000.c b/arch/avr32/mach-at32ap/at32ap7000.c
index 32c7045141c2..6eeda60b8288 100644
--- a/arch/avr32/mach-at32ap/at32ap7000.c
+++ b/arch/avr32/mach-at32ap/at32ap7000.c
@@ -504,6 +504,21 @@ static inline void set_ebi_sfr_bits(u32 mask)
 }
 
 /* --------------------------------------------------------------------
+ *  System Timer/Counter (TC)
+ * -------------------------------------------------------------------- */
+static struct resource at32_systc0_resource[] = {
+        PBMEM(0xfff00c00),
+        IRQ(22),
+};
+struct platform_device at32_systc0_device = {
+        .name           = "systc",
+        .id             = 0,
+        .resource       = at32_systc0_resource,
+        .num_resources  = ARRAY_SIZE(at32_systc0_resource),
+};
+DEV_CLK(pclk, at32_systc0, pbb, 3);
+
+/* --------------------------------------------------------------------
  *  PIO
  * -------------------------------------------------------------------- */
 
@@ -551,6 +566,8 @@ void __init at32_add_system_devices(void)
         platform_device_register(&smc0_device);
         platform_device_register(&pdc_device);
 
+        platform_device_register(&at32_systc0_device);
+
         platform_device_register(&pio0_device);
         platform_device_register(&pio1_device);
         platform_device_register(&pio2_device);
@@ -1000,6 +1017,7 @@ struct clk *at32_clock_list[] = {
         &pio2_mck,
         &pio3_mck,
         &pio4_mck,
+        &at32_systc0_pclk,
         &atmel_usart0_usart,
         &atmel_usart1_usart,
         &atmel_usart2_usart,