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?
> + if (!ret)
> + i2c_mark_adapter_resumed(&i2c_dev->adapter);
> +
> + return ret;
A very minor nit.. will be a bit more straightforward to write this as:
int err;
err = tegra_i2c_init(i2c_dev, false);
if (err)
return err;
i2c_mark_adapter_resumed(&i2c_dev->adapter);
return 0;
It is always cleaner to return 0 on success.
--
Dmitry
