From mboxrd@z Thu Jan 1 00:00:00 1970 From: ccross@android.com (Colin Cross) Date: Tue, 17 May 2011 10:06:07 -0700 Subject: [PATCH] ARM: smp_twd: Reconfigure clockevents after cpufreq change In-Reply-To: <4DD27F7D.2070305@ti.com> References: <1305588114-23728-1-git-send-email-ccross@android.com> <4DD27F7D.2070305@ti.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, May 17, 2011 at 7:00 AM, Santosh Shilimkar wrote: > Colin, > > On 5/17/2011 4:51 AM, Colin Cross wrote: >> >> The localtimer's clock changes with the cpu clock. ?After a >> cpufreq transition, update the clockevent's frequency and >> reprogram the next clock event. >> >> Adds a clock called "smp_twd" that is used to determine the >> twd frequency, which can also be used at init time to >> avoid calibrating the twd frequency. >> >> Signed-off-by: Colin Cross >> Cc: Thomas Gleixner >> Cc: Russell King >> Cc: Santosh Shilimkar >> Cc: Rob Herring >> --- >> ?arch/arm/kernel/smp_twd.c | ? 69 >> +++++++++++++++++++++++++++++++++++++++++++-- >> ?1 files changed, 66 insertions(+), 3 deletions(-) >> >> This patch depends on Thomas Gleixner's patch to add >> clockevents_reconfigure >> See: https://lkml.org/lkml/2011/5/13/122 >> >> This patch adds a clock that can be used to skip calibration as well >> as update the frequency. ?A later patch (or a later version of this patch) >> will drop twd_calibrate_rate once all platforms provide the necessary >> smp_twd clock. >> > > Since the "smp_twd" clock node will not have a clk_set_rate() > associated with it, will the clk_get_rate() gives you real > rate. May be we can associate this node as a child of > CPU clock node and use the fixed divider based on peripheral > ratio. Is that the idea here to realize it ? Yes, the idea is that it will be a fixed divider off the cpu clock, which will have been updated by cpufreq.