Messages in this thread | | | Date | Wed, 22 Apr 2015 13:30:53 +0200 | From | Alexandre Belloni <> | Subject | Re: [PATCH V2] drivers/rtc/rtc-ds1307.c: Enable the mcp794xx alarm after programming time |
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On 21/04/2015 at 20:59:15 -0500, Nishanth Menon wrote : > >> Why is that so? when set alarm is requested for time X, you want > >> interrupt at time X, not an interrupt for previous configured RTC > >> alarm time! > >> > > > > You expect at least an interrupt. > > And you will get an interrupt if the event occurs before the i2c burst > starts. Once the i2cburst does start, you are committing to the new time. >
You mean that even if ALM0EN is set after ALM0IF was set to 1, it will trigger the interrupt? I had a look at the MFP output block diagram would let me think that this is the case. I was thinking otherwise before. If that is so, then indeed, your patch is OK.
My concern was about the time between ds1307->write_block_data() and i2c_smbus_write_byte_data() which actually calls cond_sched().
I fully agree that your patch doesn't change the behaviour for the other cases you presented and further clean up is to be done in a separate set of patches.
-- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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