diff options
| author | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2015-08-16 11:23:44 +0200 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2015-10-06 12:25:11 +0200 |
| commit | 216ab8f155fba659e06df240862cf59acb8b7be5 (patch) | |
| tree | 96de6aef0c2f144f8719054c177656b685e1241f /drivers/clocksource | |
| parent | 6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff) | |
clocksource: atmel-st: get and use slow clock
The current slow clock rate is hardcoded. Properly get the slow clock
and use its rate.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/timer-atmel-st.c | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c index 41b7b6dc1d0d..29d21d68df5a 100644 --- a/drivers/clocksource/timer-atmel-st.c +++ b/drivers/clocksource/timer-atmel-st.c @@ -22,6 +22,7 @@ #include <linux/kernel.h> #include <linux/interrupt.h> #include <linux/irq.h> +#include <linux/clk.h> #include <linux/clockchips.h> #include <linux/export.h> #include <linux/mfd/syscon.h> @@ -33,9 +34,7 @@ static unsigned long last_crtr; static u32 irqmask; static struct clock_event_device clkevt; static struct regmap *regmap_st; - -#define AT91_SLOW_CLOCK 32768 -#define RM9200_TIMER_LATCH ((AT91_SLOW_CLOCK + HZ/2) / HZ) +static int timer_latch; /* * The ST_CRTR is updated asynchronously to the master clock ... but @@ -82,8 +81,8 @@ static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id) if (sr & AT91_ST_PITS) { u32 crtr = read_CRTR(); - while (((crtr - last_crtr) & AT91_ST_CRTV) >= RM9200_TIMER_LATCH) { - last_crtr += RM9200_TIMER_LATCH; + while (((crtr - last_crtr) & AT91_ST_CRTV) >= timer_latch) { + last_crtr += timer_latch; clkevt.event_handler(&clkevt); } return IRQ_HANDLED; @@ -144,7 +143,7 @@ static int clkevt32k_set_periodic(struct clock_event_device *dev) /* PIT for periodic irqs; fixed rate of 1/HZ */ irqmask = AT91_ST_PITS; - regmap_write(regmap_st, AT91_ST_PIMR, RM9200_TIMER_LATCH); + regmap_write(regmap_st, AT91_ST_PIMR, timer_latch); regmap_write(regmap_st, AT91_ST_IER, irqmask); return 0; } @@ -197,7 +196,8 @@ static struct clock_event_device clkevt = { */ static void __init atmel_st_timer_init(struct device_node *node) { - unsigned int val; + struct clk *sclk; + unsigned int sclk_rate, val; int irq, ret; regmap_st = syscon_node_to_regmap(node); @@ -221,6 +221,19 @@ static void __init atmel_st_timer_init(struct device_node *node) if (ret) panic(pr_fmt("Unable to setup IRQ\n")); + sclk = of_clk_get(node, 0); + if (IS_ERR(sclk)) + panic(pr_fmt("Unable to get slow clock\n")); + + clk_prepare_enable(sclk); + if (ret) + panic(pr_fmt("Could not enable slow clock\n")); + + sclk_rate = clk_get_rate(sclk); + if (!sclk_rate) + panic(pr_fmt("Invalid slow clock rate\n")); + timer_latch = (sclk_rate + HZ / 2) / HZ; + /* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used * directly for the clocksource and all clockevents, after adjusting * its prescaler from the 1 Hz default. @@ -229,11 +242,11 @@ static void __init atmel_st_timer_init(struct device_node *node) /* Setup timer clockevent, with minimum of two ticks (important!!) */ clkevt.cpumask = cpumask_of(0); - clockevents_config_and_register(&clkevt, AT91_SLOW_CLOCK, + clockevents_config_and_register(&clkevt, sclk_rate, 2, AT91_ST_ALMV); /* register clocksource */ - clocksource_register_hz(&clk32k, AT91_SLOW_CLOCK); + clocksource_register_hz(&clk32k, sclk_rate); } CLOCKSOURCE_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st", atmel_st_timer_init); |