This patch does the following 1. Handle the return values of wait_for_completion_interruptible_timeout 2. Add spin locks to avoid race conditions during ISR. Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx> Cc: Doug Anderson <dianders@xxxxxxxxxxxx> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx> --- Discussion thread for this patch can be found at http://www.gossamer-threads.com/lists/linux/kernel/1693284?page=last I've not seen any reference to spin lock usage in IIO. Kindly, suggest me if there is a better way to avoid the race. Thanks, Naveen drivers/iio/adc/exynos_adc.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c index ed6fdd7..4de28ae 100644 --- a/drivers/iio/adc/exynos_adc.c +++ b/drivers/iio/adc/exynos_adc.c @@ -91,6 +91,7 @@ struct exynos_adc { struct completion completion; + spinlock_t reg_lock; u32 value; unsigned int version; }; @@ -117,7 +118,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev, long mask) { struct exynos_adc *info = iio_priv(indio_dev); - unsigned long timeout; + long timeout; u32 con1, con2; if (mask != IIO_CHAN_INFO_RAW) @@ -143,15 +144,19 @@ static int exynos_read_raw(struct iio_dev *indio_dev, ADC_V1_CON(info->regs)); } + INIT_COMPLETION(info->completion); + timeout = wait_for_completion_interruptible_timeout (&info->completion, EXYNOS_ADC_TIMEOUT); + *val = info->value; mutex_unlock(&indio_dev->mlock); if (timeout == 0) return -ETIMEDOUT; - + else if (timeout < 0) + return timeout; return IIO_VAL_INT; } @@ -159,6 +164,8 @@ static irqreturn_t exynos_adc_isr(int irq, void *dev_id) { struct exynos_adc *info = (struct exynos_adc *)dev_id; + spin_lock(&info->reg_lock); + /* Read value */ info->value = readl(ADC_V1_DATX(info->regs)) & ADC_DATX_MASK; @@ -170,6 +177,8 @@ static irqreturn_t exynos_adc_isr(int irq, void *dev_id) complete(&info->completion); + spin_unlock(&info->reg_lock); + return IRQ_HANDLED; } @@ -327,6 +336,7 @@ static int exynos_adc_probe(struct platform_device *pdev) else indio_dev->num_channels = MAX_ADC_V2_CHANNELS; + spin_lock_init(&info->reg_lock); ret = iio_device_register(indio_dev); if (ret) goto err_irq; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
