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iio: imx8qxp-adc: fix irq flood when call imx8qxp_adc_read_raw() 

irq flood happen when run
    cat /sys/bus/iio/devices/iio:device0/in_voltage1_raw

imx8qxp_adc_read_raw()
{
	...
	enable irq
	/* adc start */
	writel(1, adc->regs + IMX8QXP_ADR_ADC_SWTRIG);
	^^^^ trigger irq flood.
	wait_for_completion_interruptible_timeout();
	readl(adc->regs + IMX8QXP_ADR_ADC_RESFIFO);
	^^^^ clear irq here.
	...
}

There is only FIFO watermark interrupt at this ADC controller.
IRQ line will be assert until software read data from FIFO.
So IRQ flood happen during wait_for_completion_interruptible_timeout().

Move FIFO read into irq handle to avoid irq flood.

Fixes: 1e23dcaa1a ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC")
Cc: stable@vger.kernel.org

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Cai Huoqing <cai.huoqing@linux.dev>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20221201140110.2653501-1-Frank.Li@nxp.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Frank Li 2022-12-01 09:01:10 -05:00 committed by Jonathan Cameron
parent 6794ed0cfc
commit 0fc3562a99
1 changed files with 9 additions and 2 deletions
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11
drivers/iio/adc/imx8qxp-adc.c
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@ -86,6 +86,8 @@
#define IMX8QXP_ADC_TIMEOUT msecs_to_jiffies(100)
#define IMX8QXP_ADC_MAX_FIFO_SIZE 16
struct imx8qxp_adc {
struct device *dev;
void __iomem *regs;
@ -95,6 +97,7 @@ struct imx8qxp_adc {
/* Serialise ADC channel reads */
struct mutex lock;
struct completion completion;
u32 fifo[IMX8QXP_ADC_MAX_FIFO_SIZE];
};
#define IMX8QXP_ADC_CHAN(_idx) { \
@ -238,8 +241,7 @@ static int imx8qxp_adc_read_raw(struct iio_dev *indio_dev,
return ret;
}
*val = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
readl(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));
*val = adc->fifo[0];
mutex_unlock(&adc->lock);
return IIO_VAL_INT;
@ -265,10 +267,15 @@ static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
{
struct imx8qxp_adc *adc = dev_id;
u32 fifo_count;
int i;
fifo_count = FIELD_GET(IMX8QXP_ADC_FCTRL_FCOUNT_MASK,
readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL));
for (i = 0; i < fifo_count; i++)
adc->fifo[i] = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
readl_relaxed(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));
if (fifo_count)
complete(&adc->completion);