diff mbox series

[U-Boot,V2,2/4] imx: lpi2c: fix clock issue when NACK detected

Message ID 20180708034643.10380-2-peng.fan@nxp.com
State Awaiting Upstream
Delegated to: Heiko Schocher
Headers show
Series [U-Boot,V2,1/4] imx_lpi2c: Update lpi2c driver to support imx8 | expand

Commit Message

Peng Fan July 8, 2018, 3:46 a.m. UTC 
From: Gao Pan <pandy.gao@nxp.com>

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>
---

V2: Add review tag

 drivers/i2c/imx_lpi2c.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

Heiko Schocher July 12, 2018, 2:09 p.m. UTC | #1 
Hello Peng,

Am 08.07.2018 um 05:46 schrieb Peng Fan:
> From: Gao Pan <pandy.gao@nxp.com>
> 
> 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>
> ---
> 
> V2: Add review tag
> 
>   drivers/i2c/imx_lpi2c.c | 14 ++++++++++----
>   1 file changed, 10 insertions(+), 4 deletions(-)

Applied to u-boot-i2c.git master

Thanks!

bye,
Heiko
diff mbox series

Patch

diff --git a/drivers/i2c/imx_lpi2c.c b/drivers/i2c/imx_lpi2c.c
index a6e41c5c91..d2e11b411b 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 @@  static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
 {
 	lpi2c_status_t result;
 	u32 status;
+	ulong start_time;
 
 	result = bus_i2c_wait_for_tx_ready(regs);
 	if (result) {
@@ -194,7 +196,8 @@  static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
 	/* 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 @@  static int bus_i2c_stop(struct imx_lpi2c_reg *regs)
 			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 @@  static int imx_lpi2c_probe_chip(struct udevice *bus, u32 chip,
 	}
 
 	result = bus_i2c_stop(regs);
-	if (result) {
+	if (result)
 		bus_i2c_init(bus, 100000);
-		return -result;
-	}
 
 	return result;
 }