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| author | Linus Walleij <linus.walleij@stericsson.com> | 2010-09-13 13:40:04 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-17 10:16:48 +0100 |
| commit | a0719f52d90aed5b82ecf2f3ed14bc4ced3d1a8a (patch) | |
| tree | 2441c3195a1d8d7d70cdbdf6c39381cae5b7cd78 /arch | |
| parent | 99f76891a33d130776da3b01935d978b1e75fe68 (diff) | |
| download | linux-stable-a0719f52d90aed5b82ecf2f3ed14bc4ced3d1a8a.tar.gz linux-stable-a0719f52d90aed5b82ecf2f3ed14bc4ced3d1a8a.tar.bz2 linux-stable-a0719f52d90aed5b82ecf2f3ed14bc4ced3d1a8a.zip | |
ARM: 6376/1: plat-nomadik: MTU: Change prescaler limit and comment updates
The prescaler 16 is now used only when the timer runs at 32 MHz
or more. Some comment updates as well.
Acked-by: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/plat-nomadik/timer.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index d673888af18e..aedf9c1d645e 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -1,5 +1,5 @@ /* - * linux/arch/arm/mach-nomadik/timer.c + * linux/arch/arm/plat-nomadik/timer.c * * Copyright (C) 2008 STMicroelectronics * Copyright (C) 2010 Alessandro Rubini @@ -75,7 +75,7 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode, cr = readl(mtu_base + MTU_CR(1)); writel(0, mtu_base + MTU_LR(1)); writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1)); - writel(0x2, mtu_base + MTU_IMSC); + writel(1 << 1, mtu_base + MTU_IMSC); break; case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: @@ -131,7 +131,7 @@ void __init nmdk_timer_init(void) { unsigned long rate; struct clk *clk0; - u32 cr; + u32 cr = MTU_CRn_32BITS; clk0 = clk_get_sys("mtu0", NULL); BUG_ON(IS_ERR(clk0)); @@ -139,12 +139,15 @@ void __init nmdk_timer_init(void) clk_enable(clk0); /* - * Tick rate is 2.4MHz for Nomadik and 110MHz for ux500: - * use a divide-by-16 counter if it's more than 16MHz + * Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz + * for ux500. + * Use a divide-by-16 counter if the tick rate is more than 32MHz. + * At 32 MHz, the timer (with 32 bit counter) can be programmed + * to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer + * with 16 gives too low timer resolution. */ - cr = MTU_CRn_32BITS;; rate = clk_get_rate(clk0); - if (rate > 16 << 20) { + if (rate > 32000000) { rate /= 16; cr |= MTU_CRn_PRESCALE_16; } else { |