commit 52d457b527c72d3d20f93339e8e11e70726da2e3
author Gao Pan <pandy.gao@nxp.com> Sun Jul 08 11:46:41 2018 +0800
committer Heiko Schocher <hs@denx.de> Thu Jul 12 11:09:07 2018 +0200
tree 538216d800839f69e7eb44f6241a4ed9df5de412
parent d9103f8a26249117337fb7920e353c9c56f775e7

imx: lpi2c: fix clock issue when NACK detected

For LPI2C IP, NACK is detected by the rising edge of the ninth clock.
In current uboot driver, once NACK is detected, it will reset and then
disable LPI2C master. As a result, we can never see the falling edge
of the ninth clock.

Signed-off-by: Gao Pan <pandy.gao@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

drivers/i2c/imx_lpi2c.c

diff --git a/drivers/i2c/imx_lpi2c.c b/drivers/i2c/imx_lpi2c.c
index a6e41c5..d2e11b4 100644
--- a/drivers/i2c/imx_lpi2c.c
+++ b/drivers/i2c/imx_lpi2c.c
@@ -15,6 +15,7 @@
 #include <i2c.h>
 
 #define LPI2C_FIFO_SIZE 4
+#define LPI2C_NACK_TOUT_MS 1
 #define LPI2C_TIMEOUT_MS 100
 
 /* Weak linked function for overridden by some SoC power function */
@@ -184,6 +185,7 @@
 {
 	lpi2c_status_t result;
 	u32 status;
+	ulong start_time;
 
 	result = bus_i2c_wait_for_tx_ready(regs);
 	if (result) {
@@ -194,7 +196,8 @@
 	/* send stop command */
 	writel(LPI2C_MTDR_CMD(0x2), &regs->mtdr);
 
-	while (result == LPI2C_SUCESS) {
+	start_time = get_timer(0);
+	while (1) {
 		status = readl(&regs->msr);
 		result = imx_lpci2c_check_clear_error(regs);
 		/* stop detect flag */
@@ -204,6 +207,11 @@
 			writel(status, &regs->msr);
 			break;
 		}
+
+		if (get_timer(start_time) > LPI2C_NACK_TOUT_MS) {
+			debug("stop timeout\n");
+			return -ETIMEDOUT;
+		}
 	}
 
 	return result;
@@ -363,10 +371,8 @@
 	}
 
 	result = bus_i2c_stop(regs);
-	if (result) {
+	if (result)
 		bus_i2c_init(bus, 100000);
-		return -result;
-	}
 
 	return result;
 }