The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fed1bd51a504eb96caa38b4f13ab138fc169ea75 Mon Sep 17 00:00:00 2001
From: Qii Wang qii.wang@mediatek.com Date: Thu, 27 May 2021 20:04:04 +0800 Subject: [PATCH] i2c: mediatek: Disable i2c start_en and clear intr_stat brfore reset
The i2c controller driver do dma reset after transfer timeout, but sometimes dma reset will trigger an unexpected DMA_ERR irq. It will cause the i2c controller to continuously send interrupts to the system and cause soft lock-up. So we need to disable i2c start_en and clear intr_stat to stop i2c controller before dma reset when transfer timeout.
Fixes: aafced673c06("i2c: mediatek: move dma reset before i2c reset") Signed-off-by: Qii Wang qii.wang@mediatek.com Signed-off-by: Wolfram Sang wsa@kernel.org
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index 5ddfa4e56ee2..4e9fb6b44436 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -479,6 +479,11 @@ static void mtk_i2c_clock_disable(struct mtk_i2c *i2c) static void mtk_i2c_init_hw(struct mtk_i2c *i2c) { u16 control_reg; + u16 intr_stat_reg; + + mtk_i2c_writew(i2c, I2C_CHN_CLR_FLAG, OFFSET_START); + intr_stat_reg = mtk_i2c_readw(i2c, OFFSET_INTR_STAT); + mtk_i2c_writew(i2c, intr_stat_reg, OFFSET_INTR_STAT);
if (i2c->dev_comp->apdma_sync) { writel(I2C_DMA_WARM_RST, i2c->pdmabase + OFFSET_RST);