On Tue, Apr 28, 2020 at 02:18:13PM +0800, Bibby Hsieh wrote:
> Although in the most platforms, the bus power of i2c
> are alway on, some platforms disable the i2c bus power
> in order to meet low power request.
> 
> We get and enable bulk regulator in i2c adapter device.
> 
> Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
> ---
>  drivers/i2c/i2c-core-base.c | 82 +++++++++++++++++++++++++++++++++++++
>  include/linux/i2c.h         |  2 +
>  2 files changed, 84 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 5cc0b0ec5570..f81b42a4ed07 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -313,6 +313,7 @@ static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
>  static int i2c_device_probe(struct device *dev)
>  {
>  	struct i2c_client	*client = i2c_verify_client(dev);
> +	struct i2c_adapter	*adap = client->adapter;

You are accessing client before the NULL pointer check.


> @@ -414,6 +421,7 @@ static int i2c_device_probe(struct device *dev)
>  static int i2c_device_remove(struct device *dev)
>  {
>  	struct i2c_client	*client = i2c_verify_client(dev);
> +	struct i2c_adapter      *adap = client->adapter;

Same here.

> +static int i2c_suspend_late(struct device *dev)
> +{
> +	struct i2c_client *client = i2c_verify_client(dev);
> +	struct i2c_adapter *adap = client->adapter;
> +	int err;
> +
> +	err = pm_generic_suspend_late(&client->dev);
> +	if (err)
> +		return err;
> +
> +	if (!pm_runtime_status_suspended(&client->dev))
> +		return regulator_disable(adap->bus_regulator);
> +
> +	return err;

Can be 'return 0'.