From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrzej Hajda Subject: [PATCH v2] i2c: exynos5: disable fifo-almost-empty irq signal when necessary Date: Wed, 22 Feb 2017 11:11:20 +0100 Message-ID: <1487758280-22801-1-git-send-email-a.hajda@samsung.com> References: Return-path: Sender: linux-samsung-soc-owner@vger.kernel.org To: Wolfram Sang , Krzysztof Kozlowski , Javier Martinez Canillas , linux-i2c@vger.kernel.org, linux-samsung-soc@vger.kernel.org Cc: Andrzej Hajda , Bartlomiej Zolnierkiewicz , Marek Szyprowski List-Id: linux-i2c@vger.kernel.org Fifo-almost-empty irq signal should be disabled as soon as possible, to avoid unnecessary interrupt storm. The best moment is when there is no more data to feed fifo. This patch fixes system stalls caused by IRQ storm. Signed-off-by: Andrzej Hajda --- v2: - removed doubled conditional drivers/i2c/busses/i2c-exynos5.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c index bea6071..00e81e3 100644 --- a/drivers/i2c/busses/i2c-exynos5.c +++ b/drivers/i2c/busses/i2c-exynos5.c @@ -502,8 +502,13 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id) fifo_level = HSI2C_TX_FIFO_LVL(fifo_status); len = i2c->variant->fifo_depth - fifo_level; - if (len > (i2c->msg->len - i2c->msg_ptr)) + if (len > (i2c->msg->len - i2c->msg_ptr)) { + u32 int_en = readl(i2c->regs + HSI2C_INT_ENABLE); + + int_en &= ~HSI2C_INT_TX_ALMOSTEMPTY_EN; + writel(int_en, i2c->regs + HSI2C_INT_ENABLE); len = i2c->msg->len - i2c->msg_ptr; + } while (len > 0) { byte = i2c->msg->buf[i2c->msg_ptr++]; -- 2.7.4