linux-kernel - [PATCH 3.16 231/357] iio: adc: at91: dont use the last converted data register

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Date:	Fri,  3 Oct 2014 14:30:17 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Ludovic Desroches <ludovic.desroches@...el.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jonathan Cameron <jic23@...nel.org>
Subject: [PATCH 3.16 231/357] iio: adc: at91: dont use the last converted data register

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ludovic Desroches <ludovic.desroches@...el.com>

commit d4f51956ac8ad302db9b0c4e4232775b1baa7b44 upstream.

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@...el.com>
Acked-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
Signed-off-by: Jonathan Cameron <jic23@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iio/adc/at91_adc.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -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, str
 		disable_irq_nosync(irq);
 		iio_trigger_poll(idev->trig, iio_get_time_ns());
 	} 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
 	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_interrup
 		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_
 	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_
 
 		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;


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