i2c: hisi: Add clearing tx aempty interrupt operation

The driver receives the tx fifo almost empty(aempty) interrupt and
reads the tx_aempty_int_mstat to start a round of data transfer.
The operation of clearing the TX aempty interrupt after completing
a write cycle is added to ensure that the FIFO is truly at almost
empty status when an aempty interrupt is received.
The threshold for fifo almost empty interrupt is defined as 1.

Signed-off-by: Devyn Liu <liudingyuan@huawei.com>
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index cd37053362ee1b1e3e980a02dc4050a95a6a14b0..975c0b1c44deb61ae84bfbe877de390f01502c60 100644 (file)
--- a/drivers/i2c/busses/i2c-hisi.c
+++ b/drivers/i2c/busses/i2c-hisi.c
@@ -57,6 +57,8 @@
 #define   HISI_I2C_FS_SPK_LEN_CNT      GENMASK(7, 0)
 #define HISI_I2C_HS_SPK_LEN            0x003c
 #define   HISI_I2C_HS_SPK_LEN_CNT      GENMASK(7, 0)
+#define HISI_I2C_TX_INT_CLR            0x0040
+#define   HISI_I2C_TX_AEMPTY_INT               BIT(0)
 #define HISI_I2C_INT_MSTAT             0x0044
 #define HISI_I2C_INT_CLR               0x0048
 #define HISI_I2C_INT_MASK              0x004C
@@ -124,6 +126,11 @@ static void hisi_i2c_clear_int(struct hisi_i2c_controller *ctlr, u32 mask)
        writel_relaxed(mask, ctlr->iobase + HISI_I2C_INT_CLR);
 }
 
+static void hisi_i2c_clear_tx_int(struct hisi_i2c_controller *ctlr, u32 mask)
+{
+       writel_relaxed(mask, ctlr->iobase + HISI_I2C_TX_INT_CLR);
+}
+
 static void hisi_i2c_handle_errors(struct hisi_i2c_controller *ctlr)
 {
        u32 int_err = ctlr->xfer_err, reg;
@@ -168,6 +175,7 @@ static int hisi_i2c_start_xfer(struct hisi_i2c_controller *ctlr)
        writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL);
 
        hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL);
+       hisi_i2c_clear_tx_int(ctlr, HISI_I2C_TX_AEMPTY_INT);
        hisi_i2c_enable_int(ctlr, HISI_I2C_INT_ALL);
 
        return 0;
@@ -323,6 +331,8 @@ static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr)
         */
        if (ctlr->msg_tx_idx == ctlr->msg_num)
                hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY);
+
+       hisi_i2c_clear_tx_int(ctlr, HISI_I2C_TX_AEMPTY_INT);
 }
 
 static irqreturn_t hisi_i2c_irq(int irq, void *context)
@@ -363,6 +373,7 @@ out:
        if (int_stat & HISI_I2C_INT_TRANS_CPLT) {
                hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL);
                hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL);
+               hisi_i2c_clear_tx_int(ctlr, HISI_I2C_TX_AEMPTY_INT);
                complete(ctlr->completion);
        }