On Fri, Jul 6, 2012 at 11:48 PM, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: > On 07/06/2012 06:45 PM, anish kumar wrote: >> On Fri, 2012-07-06 at 14:25 +0100, Jonathan Cameron wrote: >>> On 7/6/2012 1:00 PM, anish singh wrote: >>>> Hello Jonathan, >>>> >>>> I would be extremely happy if I can get your opinion on this. >>>> >>>> Recently Myungjoo Ham had posted Extcon: adc-jack driver patch. >>>> >>>> Description of this driver: >>>> This is basically a Headset(jack) driver.Once the headset is inserted >>>> a irq_handler is called and in this handler we have a callback(this >>>> callback calls into pmic driver to get the adc value) to get >>>> the adc value to determine the kind of headset: This headset could >>>> be headset with mic, headset without mic or headset with >>>> keys(volume-up/down) attached to it.One we have found out the kind >>>> of headset we use extcon framework to notify the other interested drivers or >>>> userspace that a headset with so and so capabilities has been inserted. >>>> >>>> Question: >>>> Does this driver fall into IIO as pointed by Mark Brown in his review comments? >>> The driver itself probably doesn't, but the adc part does in that IIO >>> provides a means of talking to the relevant adc. >>>> >>>> Why do we need to use IIO to get the adc value?As for different boards the >>>> method of getting adc is different.How does IIO help in this? >>> Ultimately, IIO in this case is acting as an infrastructure for ALL >>> adcs. E.g. for different boards you'll need a mapping to tell it which >>> adc channel is connected but that is it. Hence you don't need a >>> specific callback for each pmic as you will be using generic interfaces >>> to query it. >> After having a brief glance at IIO below is my understanding: >> IIO is used to provide standard interfaces in the form of sysfs to >> userspace _ONLY_. >> >> My requirement: >> ADC-JACK-Driver should get the adc value from other driver i.e. PMIC >> driver.Here the requirement is communication between two drivers in >> kernel.Can IIO be used here? >> >> I had a look at drivers/staging/iio/Documentation/Overview.txt and some >> ADC drivers. > > Hi, > > There is a new experimental in kernel API, which lets you write IIO clients > in the kernel. > > See: drivers/iio/inkern.h > and drivers/staging/iio/iio_hwmon.c Thanks for this.So below is my understanding: 1.The driver which will provide adc value should first register itself with IIO core by specifiying it channels(struct iio_map should be used) and what values we can expect from it. 2.The driver which is interested in reading the adc values should call iio_channel_get to get the channel. 3.Once the channel is obtained we can call iio_st_read_channel_raw function to read the values. Is my understanding right or I am completely lost here? > > - Lars > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
