i2c: mediatek: Add i2c and apdma sync in i2c driver

When i2c and apdma use different source clocks, we should enable
synchronization between them.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-mt65xx.c

@@ -77,6 +77,8 @@
 #define I2C_CONTROL_DIR_CHANGE          (0x1 << 4)
 #define I2C_CONTROL_ACKERR_DET_EN       (0x1 << 5)
 #define I2C_CONTROL_TRANSFER_LEN_CHANGE (0x1 << 6)
+#define I2C_CONTROL_DMAACK_EN           (0x1 << 8)
+#define I2C_CONTROL_ASYNC_MODE          (0x1 << 9)
 #define I2C_CONTROL_WRAPPER             (0x1 << 0)
 
 #define I2C_DRV_NAME		"i2c-mt65xx"
@@ -169,6 +171,7 @@ struct mtk_i2c_compatible {
 	unsigned char aux_len_reg: 1;
 	unsigned char support_33bits: 1;
 	unsigned char timing_adjust: 1;
+	unsigned char dma_sync: 1;
 };
 
 struct mtk_i2c {
@@ -218,6 +221,7 @@ static const struct mtk_i2c_compatible mt2712_compat = {
 	.aux_len_reg = 1,
 	.support_33bits = 1,
 	.timing_adjust = 1,
+	.dma_sync = 0,
 };
 
 static const struct mtk_i2c_compatible mt6577_compat = {
@@ -229,6 +233,7 @@ static const struct mtk_i2c_compatible mt6577_compat = {
 	.aux_len_reg = 0,
 	.support_33bits = 0,
 	.timing_adjust = 0,
+	.dma_sync = 0,
 };
 
 static const struct mtk_i2c_compatible mt6589_compat = {
@@ -240,6 +245,7 @@ static const struct mtk_i2c_compatible mt6589_compat = {
 	.aux_len_reg = 0,
 	.support_33bits = 0,
 	.timing_adjust = 0,
+	.dma_sync = 0,
 };
 
 static const struct mtk_i2c_compatible mt7622_compat = {
@@ -251,6 +257,7 @@ static const struct mtk_i2c_compatible mt7622_compat = {
 	.aux_len_reg = 1,
 	.support_33bits = 0,
 	.timing_adjust = 0,
+	.dma_sync = 0,
 };
 
 static const struct mtk_i2c_compatible mt8173_compat = {
@@ -261,6 +268,7 @@ static const struct mtk_i2c_compatible mt8173_compat = {
 	.aux_len_reg = 1,
 	.support_33bits = 1,
 	.timing_adjust = 0,
+	.dma_sync = 0,
 };
 
 static const struct of_device_id mtk_i2c_of_match[] = {
@@ -360,6 +368,9 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 
 	control_reg = I2C_CONTROL_ACKERR_DET_EN |
 		      I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
+	if (i2c->dev_comp->dma_sync)
+		control_reg |= I2C_CONTROL_DMAACK_EN | I2C_CONTROL_ASYNC_MODE;
+
 	mtk_i2c_writew(i2c, control_reg, OFFSET_CONTROL);
 	mtk_i2c_writew(i2c, I2C_DELAY_LEN, OFFSET_DELAY_LEN);