Re: [PATCH] clocksource: dw_apb_timer_of: support timer-based delay

From: Daniel Lezcano
Date: Fri Oct 30 2015 - 06:44:53 EST


On 10/30/2015 09:27 AM, Jisheng Zhang wrote:
Implement an ARM delay timer to be used for udelay(). This allows us to
skip the delay loop calibration at boot on Marvell BG2, BG2Q, BG2CD
platforms. And after this patch, udelay() will be unaffected by CPU
frequency changes.

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
---
drivers/clocksource/Kconfig | 10 ++++++++++
drivers/clocksource/dw_apb_timer_of.c | 16 ++++++++++++++++
2 files changed, 26 insertions(+)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index a7726db..7b081805 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -29,6 +29,16 @@ config DW_APB_TIMER_OF
select DW_APB_TIMER
select CLKSRC_OF

+config DW_APB_TIMER_BASED_DELAY
+ bool "DW APB timer based delay"
+ depends on ARM && DW_APB_TIMER_OF
+ default n
+ help
+ This option enables support for using the DW APB timer to
+ implement timer-based delay. It is useful for skiping the
+ delay loop calibration at boot on some platforms. And the
+ udelay() will be unaffected by CPU frequency changes.
+

Why do you want it to be optional ?

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