Commit 0fc3562a authored by Frank Li's avatar Frank Li Committed by Jonathan Cameron
Browse files

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: 1e23dcaa ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC")
Cc: stable@vger.kernel.org

Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Reviewed-by: default avatarCai Huoqing <cai.huoqing@linux.dev>
Reviewed-by: default avatarHaibo 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: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 6794ed0c

drivers/iio/adc/imx8qxp-adc.c

+9 −2
Original line number Diff line number Diff line
@@ -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);