[U-Boot] [PATCH 26/41] lpi2c: Add bus busy error handling

[Peng Fan]

From: Ye Li <ye.li at nxp.com>

When doing "i2c dev 4; i2c probe" with ENET daughter card connected
on iMX8QXP MEK board, we met a i2c bus busy issue, that the BBF of
lpi2c always show busy, but the master is idle, and stop is detected
(SDF set).

This patch addes a handling to re-init the lpi2c master for this
case. Then the issue can be worked around.

Signed-off-by: Ye Li <ye.li at nxp.com>
Acked-by: Peng Fan <peng.fan at nxp.com>
Cc: Heiko Schocher <hs at denx.de>
---
 drivers/i2c/imx_lpi2c.c | 53 +++++++++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 21 deletions(-)

diff --git a/drivers/i2c/imx_lpi2c.c b/drivers/i2c/imx_lpi2c.c
index 585787a35c..ff07ca34aa 100644
--- a/drivers/i2c/imx_lpi2c.c
+++ b/drivers/i2c/imx_lpi2c.c
@@ -18,6 +18,8 @@
 #define LPI2C_NACK_TOUT_MS 1
 #define LPI2C_TIMEOUT_MS 100
 
+static int bus_i2c_init(struct udevice *bus, int speed);
+
 /* Weak linked function for overridden by some SoC power function */
 int __weak init_i2c_power(unsigned i2c_num)
 {
@@ -91,8 +93,9 @@ static int bus_i2c_wait_for_tx_ready(struct imx_lpi2c_reg *regs)
 	return result;
 }
 
-static int bus_i2c_send(struct imx_lpi2c_reg *regs, u8 *txbuf, int len)
+static int bus_i2c_send(struct udevice *bus, u8 *txbuf, int len)
 {
+	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 	lpi2c_status_t result = LPI2C_SUCESS;
 
 	/* empty tx */
@@ -111,8 +114,9 @@ static int bus_i2c_send(struct imx_lpi2c_reg *regs, u8 *txbuf, int len)
 	return result;
 }
 
-static int bus_i2c_receive(struct imx_lpi2c_reg *regs, u8 *rxbuf, int len)
+static int bus_i2c_receive(struct udevice *bus, u8 *rxbuf, int len)
 {
+	struct imx_lpi2c_reg *regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 	lpi2c_status_t result = LPI2C_SUCESS;
 	u32 val;
 	ulong start_time = get_timer(0);
@@ -153,15 +157,24 @@ static int bus_i2c_receive(struct imx_lpi2c_reg *regs, u8 *rxbuf, int len)
 	return result;
 }
 
-static int bus_i2c_start(struct imx_lpi2c_reg *regs, u8 addr, u8 dir)
+static int bus_i2c_start(struct udevice *bus, u8 addr, u8 dir)
 {
 	lpi2c_status_t result;
+	struct imx_lpi2c_reg *regs =
+		(struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 	u32 val;
 
 	result = imx_lpci2c_check_busy_bus(regs);
 	if (result) {
 		debug("i2c: start check busy bus: 0x%x\n", result);
-		return result;
+
+		/* Try to init the lpi2c then check the bus busy again */
+		bus_i2c_init(bus, 100000);
+		result = imx_lpci2c_check_busy_bus(regs);
+		if (result) {
+			printf("i2c: Error check busy bus: 0x%x\n", result);
+			return result;
+		}
 	}
 	/* clear all status flags */
 	writel(0x7f00, &regs->msr);
@@ -181,9 +194,11 @@ static int bus_i2c_start(struct imx_lpi2c_reg *regs, u8 addr, u8 dir)
 	return result;
 }
 
-static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
+static int bus_i2c_stop(struct udevice *bus)
 {
 	lpi2c_status_t result;
+	struct imx_lpi2c_reg *regs =
+		(struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 	u32 status;
 	ulong start_time;
 
@@ -217,28 +232,28 @@ static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
 	return result;
 }
 
-static int bus_i2c_read(struct imx_lpi2c_reg *regs, u32 chip, u8 *buf, int len)
+static int bus_i2c_read(struct udevice *bus, u32 chip, u8 *buf, int len)
 {
 	lpi2c_status_t result;
 
-	result = bus_i2c_start(regs, chip, 1);
+	result = bus_i2c_start(bus, chip, 1);
 	if (result)
 		return result;
-	result = bus_i2c_receive(regs, buf, len);
+	result = bus_i2c_receive(bus, buf, len);
 	if (result)
 		return result;
 
 	return result;
 }
 
-static int bus_i2c_write(struct imx_lpi2c_reg *regs, u32 chip, u8 *buf, int len)
+static int bus_i2c_write(struct udevice *bus, u32 chip, u8 *buf, int len)
 {
 	lpi2c_status_t result;
 
-	result = bus_i2c_start(regs, chip, 0);
+	result = bus_i2c_start(bus, chip, 0);
 	if (result)
 		return result;
-	result = bus_i2c_send(regs, buf, len);
+	result = bus_i2c_send(bus, buf, len);
 	if (result)
 		return result;
 
@@ -353,18 +368,16 @@ static int bus_i2c_init(struct udevice *bus, int speed)
 static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
 				u32 chip_flags)
 {
-	struct imx_lpi2c_reg *regs;
 	lpi2c_status_t result;
 
-	regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
-	result = bus_i2c_start(regs, chip, 0);
+	result = bus_i2c_start(bus, chip, 0);
 	if (result) {
-		bus_i2c_stop(regs);
+		bus_i2c_stop(bus);
 		bus_i2c_init(bus, 100000);
 		return result;
 	}
 
-	result = bus_i2c_stop(regs);
+	result = bus_i2c_stop(bus);
 	if (result)
 		bus_i2c_init(bus, 100000);
 
@@ -373,16 +386,14 @@ static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
 
 static int imx_lpi2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
 {
-	struct imx_lpi2c_reg *regs;
 	int ret = 0, ret_stop;
 
-	regs = (struct imx_lpi2c_reg *)devfdt_get_addr(bus);
 	for (; nmsgs > 0; nmsgs--, msg++) {
 		debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 		if (msg->flags & I2C_M_RD)
-			ret = bus_i2c_read(regs, msg->addr, msg->buf, msg->len);
+			ret = bus_i2c_read(bus, msg->addr, msg->buf, msg->len);
 		else {
-			ret = bus_i2c_write(regs, msg->addr, msg->buf,
+			ret = bus_i2c_write(bus, msg->addr, msg->buf,
 					    msg->len);
 			if (ret)
 				break;
@@ -392,7 +403,7 @@ static int imx_lpi2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
 	if (ret)
 		debug("i2c_write: error sending\n");
 
-	ret_stop = bus_i2c_stop(regs);
+	ret_stop = bus_i2c_stop(bus);
 	if (ret_stop)
 		debug("i2c_xfer: stop bus error\n");
 
-- 
2.14.1