i2c: mediatek: Fix apdma and i2c hand-shake timeout

With the apdma remove hand-shake signal, it requirs special
operation timing to reset i2c manually, otherwise the interrupt
will not be triggered, i2c transmission will be timeout.

Fixes: 8426fe70("i2c: mediatek: Add apdma sync in i2c driver")
Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-mt65xx.c

@@ -38,6 +38,7 @@
 #define I2C_IO_CONFIG_OPEN_DRAIN	0x0003
 #define I2C_IO_CONFIG_PUSH_PULL		0x0000
 #define I2C_SOFT_RST			0x0001
+#define I2C_HANDSHAKE_RST		0x0020
 #define I2C_FIFO_ADDR_CLR		0x0001
 #define I2C_DELAY_LEN			0x0002
 #define I2C_TIME_CLR_VALUE		0x0000
@@ -45,6 +46,7 @@
 #define I2C_WRRD_TRANAC_VALUE		0x0002
 #define I2C_RD_TRANAC_VALUE		0x0001
 #define I2C_SCL_MIS_COMP_VALUE		0x0000
+#define I2C_CHN_CLR_FLAG		0x0000
 
 #define I2C_DMA_CON_TX			0x0000
 #define I2C_DMA_CON_RX			0x0001
@@ -54,7 +56,9 @@
 #define I2C_DMA_START_EN		0x0001
 #define I2C_DMA_INT_FLAG_NONE		0x0000
 #define I2C_DMA_CLR_FLAG		0x0000
+#define I2C_DMA_WARM_RST		0x0001
 #define I2C_DMA_HARD_RST		0x0002
+#define I2C_DMA_HANDSHAKE_RST		0x0004
 
 #define MAX_SAMPLE_CNT_DIV		8
 #define MAX_STEP_CNT_DIV		64
@@ -475,11 +479,24 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 {
 	u16 control_reg;
 
-	writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
-	udelay(50);
-	writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
-
-	mtk_i2c_writew(i2c, I2C_SOFT_RST, OFFSET_SOFTRESET);
+	if (i2c->dev_comp->dma_sync) {
+		writel(I2C_DMA_WARM_RST, i2c->pdmabase + OFFSET_RST);
+		udelay(10);
+		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
+		udelay(10);
+		writel(I2C_DMA_HANDSHAKE_RST | I2C_DMA_HARD_RST,
+		       i2c->pdmabase + OFFSET_RST);
+		mtk_i2c_writew(i2c, I2C_HANDSHAKE_RST | I2C_SOFT_RST,
+			       OFFSET_SOFTRESET);
+		udelay(10);
+		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
+		mtk_i2c_writew(i2c, I2C_CHN_CLR_FLAG, OFFSET_SOFTRESET);
+	} else {
+		writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST);
+		udelay(50);
+		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
+		mtk_i2c_writew(i2c, I2C_SOFT_RST, OFFSET_SOFTRESET);
+	}
 
 	/* Set ioconfig */
 	if (i2c->use_push_pull)