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SubjectRe: [PATCH V2 2/7] mfd: PCF50633 adc driver
On Fri, Dec 19, 2008 at 11:18:52AM +0000, Jonathan Cameron wrote:
Hi Jonathan,
>
> This is confusingly named. To my mind it is writing the setup
> to the device not reading it.
>
> > +static void adc_read_setup(struct pcf50633 *pcf, int channel, int avg)
> > +{
> > + channel &= PCF50633_ADCC1_ADCMUX_MASK;

Yes, right. Will change.

> This needs a bit more explanation. Particularly as the data
> sheet describes that accsw as 'for rationmetric measurement'.
> Also, seeing as I assume this is the only driver that can touch
> these registers and you don't change them else where, why can't
> they be in initial setup code rather than here? (probably a good
> reason, but be nice to have it document here!)

Yes, the for killing ratiometric measurement can be in _probe. But we
need to enable accsw everytime because it's turned off automatically
once a conversion is complete - to save power.

> > + /* kill ratiometric, but enable ACCSW biasing */
> > + pcf50633_reg_write(pcf, PCF50633_REG_ADCC2, 0x00);
> > + pcf50633_reg_write(pcf, PCF50633_REG_ADCC3, 0x01);
> > +
> > + /* start ADC conversion on selected channel */
> > + pcf50633_reg_write(pcf, PCF50633_REG_ADCC1, channel | avg |
> ...
> > +
> > +static void pcf50633_adc_irq(int irq, void *data)
> > +{
> > + struct pcf50633_adc *adc = data;
> > + struct pcf50633 *pcf = adc->pcf;
> > + struct pcf50633_adc_request *req;
> > + int head;
> > + mutex_lock(&adc->queue_mutex);
> > + head = adc->queue_head;
> > +
> > + req = adc->queue[head];
> > + if (WARN_ON(!req)) {
> > + dev_err(pcf->dev, "pcf50633-adc irq: ADC queue empty!\n");
> > + mutex_unlock(&adc->queue_mutex);
> > + return;
> > + }
> > + adc->queue[head] = NULL;
>
> Weird formatting?
>

Oops! Will fix.

Thank you for the review.

Balaji Rao


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