On 6/6/19 4:52 AM, Dmitry Osipenko wrote:
06.06.2019 8:43, Bitan Biswas пишет:
On 5/31/19 5:43 AM, Dmitry Osipenko wrote:
31.05.2019 11:50, Bitan Biswas пишет:
On 5/30/19 4:27 AM, Dmitry Osipenko wrote:
30.05.2019 8:55, Bitan Biswas пишет:
Post suspend I2C registers have power on reset values. Before any
transfer initialize I2C registers to prevent I2C transfer timeout
and implement suspend and resume callbacks needed. Fix below errors
post suspend:
1) Tegra I2C transfer timeout during jetson tx2 resume:
[ 27.520613] pca953x 1-0074: calling pca953x_resume+0x0/0x1b0 @
2939, parent: i2c-1
[ 27.633623] tegra-i2c 3160000.i2c: i2c transfer timed out
[ 27.639162] pca953x 1-0074: Unable to sync registers 0x3-0x5. -110
[ 27.645336] pca953x 1-0074: Failed to sync GPIO dir registers: -110
[ 27.651596] PM: dpm_run_callback(): pca953x_resume+0x0/0x1b0
returns -110
[ 27.658375] pca953x 1-0074: pca953x_resume+0x0/0x1b0 returned -110
after 127152 usecs
[ 27.666194] PM: Device 1-0074 failed to resume: error -110
2) Tegra I2C transfer timeout error on jetson Xavier post resume.
Signed-off-by: Bitan Biswas <bbiswas@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-tegra.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/i2c/busses/i2c-tegra.c
b/drivers/i2c/busses/i2c-tegra.c
index ebaa78d..f6a377f 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1687,9 +1687,33 @@ static int tegra_i2c_remove(struct
platform_device *pdev)
}
#ifdef CONFIG_PM_SLEEP
+static int tegra_i2c_suspend(struct device *dev)
+{
+ struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+
+ i2c_mark_adapter_suspended(&i2c_dev->adapter);
+
+ return 0;
+}
+
+static int tegra_i2c_resume(struct device *dev)
+{
+ struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+ int ret;
+
+ i2c_lock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER);
+ ret = tegra_i2c_init(i2c_dev, false);
+ i2c_unlock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_ADAPTER);
Why the locking is needed here?
async resume could result in stress test issues if some client accesses
the i2c instance. This ensures the i2c instance is locked till the
initialization is complete.
1) This doesn't make much sense.. if client could access I2C during of
tegra_i2c_init execution, then what stops it to perform the access
before the lock is taken?
Client resumes will start after I2C instance resume because of driver
dependency. Since lock is the first call in i2c-tegra I believe I2C
calls of client will not start.
You're incorrectly assuming that client can start resuming in the middle
of the controller's resume process. I2C client's resume won't start
until tegra_i2c_resume() is finished completely. That is because child
drivers are resumed only after theirs parent is ready and this is
guaranteed by the drivers core.
Agreed.
-regards,
Bitan
