[PATCH v3 2/2] i2c: i2c-xiic: fix waiting/clearing while atomic

[Thilo Zirnstein <thi.zirnstein@gmail.com>]

Use non jiffies based waiting functions,
if in atomic context.

Suggested-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Thilo Zirnstein <thi.zirnstein@gmail.com>
---
 drivers/i2c/busses/i2c-xiic.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
index e68e17bdf0ba..fc9a0628cb67 100644
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c
@@ -359,16 +359,28 @@ static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask)
 	xiic_irq_en(i2c, mask);
 }

+static int xiic_poll_rx_empty(struct xiic_i2c *i2c)
+{
+	if (xiic_getreg8(i2c, XIIC_SR_REG_OFFSET) &
+	    XIIC_SR_RX_FIFO_EMPTY_MASK)
+		return 1;
+
+	xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
+	return 0;
+}
+
 static int xiic_clear_rx_fifo(struct xiic_i2c *i2c)
 {
-	u8 sr;
+	int rx_empty;
 	unsigned long timeout;

+	if (i2c->atomic)
+		return read_poll_timeout_atomic(xiic_poll_rx_empty,
+				rx_empty, rx_empty, 10, XIIC_I2C_TIMEOUT,
+				0, i2c);
+
 	timeout = jiffies + XIIC_I2C_TIMEOUT;
-	for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
-		!(sr & XIIC_SR_RX_FIFO_EMPTY_MASK);
-		sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)) {
-		xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
+	while (!xiic_poll_rx_empty(i2c)) {
 		if (time_after(jiffies, timeout)) {
 			dev_err(i2c->dev, "Failed to clear rx fifo\n");
 			return -ETIMEDOUT;
@@ -383,6 +395,12 @@ static int xiic_wait_tx_empty(struct xiic_i2c *i2c)
 	u8 isr;
 	unsigned long timeout;

+	if (i2c->atomic)
+		return read_poll_timeout_atomic(xiic_getreg32, isr,
+				isr & XIIC_INTR_TX_EMPTY_MASK, 10,
+				XIIC_I2C_TIMEOUT, 0, i2c,
+				XIIC_IISR_OFFSET);
+
 	timeout = jiffies + XIIC_I2C_TIMEOUT;
 	for (isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
 		!(isr & XIIC_INTR_TX_EMPTY_MASK);
--
2.43.0