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iio: adc: at91: don't use the last converted data register 

If touchscreen mode is enabled and a conversion is requested on another
channel, the result in the last converted data register can be a
touchscreen relative value. Starting a conversion involves to do a
conversion for all active channel. It starts with ADC channels and ends
with touchscreen channels. Then if ADC_LCD register is not read quickly,
its content may be a touchscreen conversion.
To remove this temporal constraint, the conversion value is taken from
the channel data register.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Ludovic Desroches 2014-10-09 15:02:00 +01:00 committed by Jonathan Cameron
parent 1887e724e2
commit d4f51956ac
1 changed files with 7 additions and 5 deletions
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12
drivers/iio/adc/at91_adc.c
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@ -196,6 +196,7 @@ struct at91_adc_state {
bool done;
int irq;
u16 last_value;
int chnb;
struct mutex lock;
u8 num_channels;
void __iomem *reg_base;
@ -274,7 +275,7 @@ void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
disable_irq_nosync(irq);
iio_trigger_poll(idev->trig);
} else {
st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb));
st->done = true;
wake_up_interruptible(&st->wq_data_avail);
}
@ -351,7 +352,7 @@ static irqreturn_t at91_adc_rl_interrupt(int irq, void *private)
unsigned int reg;
status &= at91_adc_readl(st, AT91_ADC_IMR);
if (status & st->registers->drdy_mask)
if (status & GENMASK(st->num_channels - 1, 0))
handle_adc_eoc_trigger(irq, idev);
if (status & AT91RL_ADC_IER_PEN) {
@ -418,7 +419,7 @@ static irqreturn_t at91_adc_9x5_interrupt(int irq, void *private)
AT91_ADC_IER_YRDY |
AT91_ADC_IER_PRDY;
if (status & st->registers->drdy_mask)
if (status & GENMASK(st->num_channels - 1, 0))
handle_adc_eoc_trigger(irq, idev);
if (status & AT91_ADC_IER_PEN) {
@ -689,9 +690,10 @@ static int at91_adc_read_raw(struct iio_dev *idev,
case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);
st->chnb = chan->channel;
at91_adc_writel(st, AT91_ADC_CHER,
AT91_ADC_CH(chan->channel));
at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
at91_adc_writel(st, AT91_ADC_IER, BIT(chan->channel));
at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
ret = wait_event_interruptible_timeout(st->wq_data_avail,
@ -708,7 +710,7 @@ static int at91_adc_read_raw(struct iio_dev *idev,
at91_adc_writel(st, AT91_ADC_CHDR,
AT91_ADC_CH(chan->channel));
at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);
at91_adc_writel(st, AT91_ADC_IDR, BIT(chan->channel));
st->last_value = 0;
st->done = false;