Messages in this thread | | | Date | Tue, 22 Feb 2011 07:28:29 -0800 | Subject | Re: [PATCH 5/7] ARM: tegra: timer: Enable timer and rtc clocks | From | Olof Johansson <> |
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On Tue, Feb 22, 2011 at 12:00 AM, Colin Cross <ccross@android.com> wrote: > On Mon, Feb 21, 2011 at 9:32 PM, Olof Johansson <olof@lixom.net> wrote: >> Hi, >> >> >> On Mon, Feb 21, 2011 at 6:39 PM, Colin Cross <ccross@android.com> wrote: >>> Enable the timer and rtc clocks to prevent them being >>> turned off by the bootloader clock disabling code. >>> >>> Signed-off-by: Colin Cross <ccross@android.com> >>> --- >>> arch/arm/mach-tegra/timer.c | 14 ++++++++++++-- >>> 1 files changed, 12 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c >>> index ffa6a68..31b4f56 100644 >>> --- a/arch/arm/mach-tegra/timer.c >>> +++ b/arch/arm/mach-tegra/timer.c >>> @@ -18,6 +18,7 @@ >>> */ >>> >>> #include <linux/init.h> >>> +#include <linux/err.h> >>> #include <linux/sched.h> >>> #include <linux/time.h> >>> #include <linux/interrupt.h> >>> @@ -193,9 +194,20 @@ static struct irqaction tegra_timer_irq = { >>> >>> static void __init tegra_init_timer(void) >>> { >>> + struct clk *clk; >>> unsigned long rate = clk_measure_input_freq(); >>> int ret; >>> >>> + clk = clk_get_sys("timer", NULL); >>> + BUG_ON(IS_ERR(clk)); >>> + clk_enable(clk); >>> + clk_put(clk); >>> + >>> + clk = clk_get_sys("rtc-tegra", NULL); >>> + BUG_ON(IS_ERR(clk)); >>> + clk_enable(clk); >>> + clk_put(clk); >> >> Why initialize the rtc clock here? Not all boards use it and instead >> use the rtc on the pmic. Seems wasteful to clock it unless the driver >> for it is probed and configured. > > timekeeping_suspend uses read_persistent_clock and not the RTC driver > to track time in suspend. The Tegra implementation of > read_persistent_clock reads from the internal RTC registers. Its a 32 > kHz clock, so it's power usage is negligible, and it is required on > all Tegra boards.
Ah, right. A short comment to that effect near the clock enablement would be useful, but other than that:
Acked-by: Olof Johansson <olof@lixom.net>
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