summaryrefslogtreecommitdiffstats
path: root/drivers/clocksource/tcb_clksrc.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/clocksource/tcb_clksrc.c')
-rw-r--r--drivers/clocksource/tcb_clksrc.c90
1 files changed, 62 insertions, 28 deletions
diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index 55d0f95f82f..32cb929b8eb 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -19,6 +19,8 @@
* - Two channels combine to create a free-running 32 bit counter
* with a base rate of 5+ MHz, packaged as a clocksource (with
* resolution better than 200 nsec).
+ * - Some chips support 32 bit counter. A single channel is used for
+ * this 32 bit free-running counter. the second channel is not used.
*
* - The third channel may be used to provide a 16-bit clockevent
* source, used in either periodic or oneshot mode. This runs
@@ -54,6 +56,11 @@ static cycle_t tc_get_cycles(struct clocksource *cs)
return (upper << 16) | lower;
}
+static cycle_t tc_get_cycles32(struct clocksource *cs)
+{
+ return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
+}
+
static struct clocksource clksrc = {
.name = "tcb_clksrc",
.rating = 200,
@@ -209,6 +216,48 @@ static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
#endif
+static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
+{
+ /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
+ __raw_writel(mck_divisor_idx /* likely divide-by-8 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP /* free-run */
+ | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
+ | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
+ tcaddr + ATMEL_TC_REG(0, CMR));
+ __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
+ __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
+ __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
+ __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
+
+ /* channel 1: waveform mode, input TIOA0 */
+ __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP, /* free-run */
+ tcaddr + ATMEL_TC_REG(1, CMR));
+ __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
+ __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
+
+ /* chain channel 0 to channel 1*/
+ __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
+ /* then reset all the timers */
+ __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+}
+
+static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx)
+{
+ /* channel 0: waveform mode, input mclk/8 */
+ __raw_writel(mck_divisor_idx /* likely divide-by-8 */
+ | ATMEL_TC_WAVE
+ | ATMEL_TC_WAVESEL_UP, /* free-run */
+ tcaddr + ATMEL_TC_REG(0, CMR));
+ __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
+ __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
+
+ /* then reset all the timers */
+ __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+}
+
static int __init tcb_clksrc_init(void)
{
static char bootinfo[] __initdata
@@ -260,34 +309,19 @@ static int __init tcb_clksrc_init(void)
divided_rate / 1000000,
((divided_rate + 500000) % 1000000) / 1000);
- /* tclib will give us three clocks no matter what the
- * underlying platform supports.
- */
- clk_enable(tc->clk[1]);
-
- /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */
- __raw_writel(best_divisor_idx /* likely divide-by-8 */
- | ATMEL_TC_WAVE
- | ATMEL_TC_WAVESEL_UP /* free-run */
- | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */
- | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */
- tcaddr + ATMEL_TC_REG(0, CMR));
- __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA));
- __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC));
- __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */
- __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR));
-
- /* channel 1: waveform mode, input TIOA0 */
- __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */
- | ATMEL_TC_WAVE
- | ATMEL_TC_WAVESEL_UP, /* free-run */
- tcaddr + ATMEL_TC_REG(1, CMR));
- __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */
- __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR));
-
- /* chain channel 0 to channel 1, then reset all the timers */
- __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR);
- __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
+ if (tc->tcb_config && tc->tcb_config->counter_width == 32) {
+ /* use apropriate function to read 32 bit counter */
+ clksrc.read = tc_get_cycles32;
+ /* setup ony channel 0 */
+ tcb_setup_single_chan(tc, best_divisor_idx);
+ } else {
+ /* tclib will give us three clocks no matter what the
+ * underlying platform supports.
+ */
+ clk_enable(tc->clk[1]);
+ /* setup both channel 0 & 1 */
+ tcb_setup_dual_chan(tc, best_divisor_idx);
+ }
/* and away we go! */
clocksource_register_hz(&clksrc, divided_rate);