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

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Date:   Thu, 24 Dec 2020 20:26:07 +0800
From:   <qii.wang@...iatek.com>
To:     <wsa@...-dreams.de>
CC:     <matthias.bgg@...il.com>, <linux-i2c@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <leilk.liu@...iatek.com>,
        <qii.wang@...iatek.com>
Subject: i2c: mediatek: Fix apdma and i2c hand-shake timeout

From: Qii Wang <qii.wang@...iatek.com>

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.

Signed-off-by: Qii Wang <qii.wang@...iatek.com>
---
 drivers/i2c/busses/i2c-mt65xx.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

base Message ID: 1605701861-30800-1-git-send-email-qii.wang@...iatek.com

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 6f61595..2ffd2f3 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/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)
-- 
1.9.1