From: Bastian Stender <bst@pengutronix.de>
To: barebox@lists.infradead.org
Cc: Bastian Stender <bst@pengutronix.de>
Subject: [PATCH] i2c: mv64xxx: add timeout waiting for bus ready
Date: Wed, 16 Aug 2017 12:16:44 +0200 [thread overview]
Message-ID: <20170816101644.20022-1-bst@pengutronix.de> (raw)
This prevents barebox hanging e.g. in case the i2c clock is accidentally
connected to GND.
Signed-off-by: Bastian Stender <bst@pengutronix.de>
---
drivers/i2c/busses/i2c-mv64xxx.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index fd1665bebb..f54d81608f 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -37,6 +37,8 @@
#define REG_CONTROL_TWSIEN 0x00000040
#define REG_CONTROL_INTEN 0x00000080
+#define MV46XXX_I2C_TIMEOUT (100 * MSECOND) /* transfer timeout */
+
/* Ctlr status values */
#define STATUS_MAST_START 0x08
#define STATUS_MAST_REPEAT_START 0x10
@@ -421,10 +423,11 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
*
*****************************************************************************
*/
-static void
+static int
mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
{
u32 status;
+ uint64_t start = get_time_ns();
do {
if (mv64xxx_read(drv_data, drv_data->reg_offsets.control) &
REG_CONTROL_IFLG) {
@@ -432,6 +435,11 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
drv_data->reg_offsets.status);
mv64xxx_i2c_fsm(drv_data, status);
mv64xxx_i2c_do_action(drv_data);
+ } else {
+ if (is_timeout(start, MV46XXX_I2C_TIMEOUT)) {
+ dev_warn(&drv_data->adapter.dev, "timeout waiting for bus ready\n");
+ return -ETIMEDOUT;
+ }
}
if (drv_data->rc) {
drv_data->state = STATE_IDLE;
@@ -440,6 +448,8 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
drv_data->block = false;
}
} while (drv_data->block);
+
+ return 0;
}
/*
@@ -453,7 +463,7 @@ static int
mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct mv64xxx_i2c_data *drv_data = container_of(adap, struct mv64xxx_i2c_data, adapter);
- int ret = num;
+ int ret;
BUG_ON(drv_data->msgs != NULL);
@@ -463,15 +473,15 @@ mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
drv_data->send_stop = (num == 1);
drv_data->block = true;
mv64xxx_i2c_send_start(drv_data);
- mv64xxx_i2c_wait_for_completion(drv_data);
+ ret = mv64xxx_i2c_wait_for_completion(drv_data);
- if (drv_data->rc < 0)
+ if (!ret && drv_data->rc < 0)
ret = drv_data->rc;
drv_data->num_msgs = 0;
drv_data->msgs = NULL;
- return ret;
+ return (ret < 0) ? ret : num;
}
/*
--
2.11.0
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next reply other threads:[~2017-08-16 10:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-16 10:16 Bastian Stender [this message]
2017-11-15 11:11 ` Bastian Stender
2017-11-17 8:48 ` Sascha Hauer
2017-11-17 9:23 ` Bastian Stender
2017-11-17 9:34 ` Sascha Hauer
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