From 0fc3562a993c3dc41d1177b3983d9300d0db1d4d Mon Sep 17 00:00:00 2001 From: Frank Li Date: Thu, 1 Dec 2022 09:01:10 -0500 Subject: [PATCH] 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: 1e23dcaa1a9f ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC") Cc: stable@vger.kernel.org Signed-off-by: Frank Li Reviewed-by: Cai Huoqing Reviewed-by: Haibo Chen Link: https://lore.kernel.org/r/20221201140110.2653501-1-Frank.Li@nxp.com Cc: Signed-off-by: Jonathan Cameron --- drivers/iio/adc/imx8qxp-adc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/imx8qxp-adc.c b/drivers/iio/adc/imx8qxp-adc.c index 36777b827165..f5a0fc9e64c5 100644 --- a/drivers/iio/adc/imx8qxp-adc.c +++ b/drivers/iio/adc/imx8qxp-adc.c @@ -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);