From mboxrd@z Thu Jan 1 00:00:00 1970 From: jic23@kernel.org (Jonathan Cameron) Date: Sat, 23 Jul 2016 08:37:47 +0200 Subject: [PATCH v2 2/4] iio: adc: add support for Allwinner SoCs ADC In-Reply-To: <26aa8f33-8525-6d82-ca17-b782c55c2c82@free-electrons.com> References: <1468576754-3273-1-git-send-email-quentin.schulz@free-electrons.com> <1468576754-3273-3-git-send-email-quentin.schulz@free-electrons.com> <578DE5C9.8070502@free-electrons.com> <26aa8f33-8525-6d82-ca17-b782c55c2c82@free-electrons.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 21/07/16 14:15, Quentin Schulz wrote: > On 20/07/2016 16:57, Jonathan Cameron wrote: >> On 19/07/16 09:33, Quentin Schulz wrote: >>> On 18/07/2016 15:18, Jonathan Cameron wrote: >>>> On 15/07/16 10:59, Quentin Schulz wrote: > [...] >>>>> + enable_irq(info->temp_data_irq); >>>> Is this hardware spitting out extra irqs? If not, much better to just >>>> leave it enabled all the time and control whether it can occur or not >>>> by controlling the device state.. >>> >>> The temp_data_irq occurs every SUNXI_GPADC_TEMP_PERIOD(x) periods (in >>> the current state of the driver: 2s). What do you mean by controlling >>> the device state? Enabling or disabling the hardware part of the IP >>> responsible of getting the temperature >>> (SUNXI_GPADC_TP_TPR_TEMP_ENABLE(x) here)? >> Yes, or something along those lines if it wakes up fast enough. > > The ADC wakes up fast enough but resets its internal time clock (I don't > know if it's the right term to use). Note that the temperature interrupt > occurs by period of X seconds in this IP. > > This means that each time we disable the ADC on the hardware side, no > temperature interrupt will occur within the first X seconds. I don't > think this is what we want. I'm guessing X is non trivial ;) So fair enough. Could you add this justification as a comment in the driver somewhere so that people coming back to this in a few years time will know what the justification for this 'unusual' handling is. Thanks, Jonathan > > [...] > > Quentin > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >