Re: [PATCH 14/22] Input: iqs626a - use cleanup facility for fwnodes

[Jeff LaBundy <jeff@labundy.com>]

Hi Dmitry,

On Tue, Sep 03, 2024 at 09:48:13PM -0700, Dmitry Torokhov wrote:
> Use __free(fwnode_handle) cleanup facility to ensure that references to
> acquired fwnodes are dropped at appropriate times automatically.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
>  drivers/input/misc/iqs626a.c | 22 ++++++----------------
>  1 file changed, 6 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/input/misc/iqs626a.c b/drivers/input/misc/iqs626a.c
> index 0dab54d3a060..7a6e6927f331 100644
> --- a/drivers/input/misc/iqs626a.c
> +++ b/drivers/input/misc/iqs626a.c
> @@ -462,7 +462,6 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  {
>  	struct iqs626_sys_reg *sys_reg = &iqs626->sys_reg;
>  	struct i2c_client *client = iqs626->client;
> -	struct fwnode_handle *ev_node;
>  	const char *ev_name;
>  	u8 *thresh, *hyst;
>  	unsigned int val;
> @@ -501,6 +500,7 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  		if (!iqs626_channels[ch_id].events[i])
>  			continue;
>  
> +		struct fwnode_handle *ev_node __free(fwnode_handle) = NULL;

This seems to deviate from what I understand to be a more conventional
style of declaring variables at the top of the scope, and separate from
actual code, like below:


	for (i = 0; i < ARRAY_SIZE(iqs626_events); i++) {
		struct fwnode_handle *ev_node __free(fwnode_handle);

		if (!iqs626_channels[ch_id].events[i])
			continue;

I also did not see any reason to explicitly declare the variable as NULL;
let me know in case I have misunderstood.

>  		if (ch_id == IQS626_CH_TP_2 || ch_id == IQS626_CH_TP_3) {
>  			/*
>  			 * Trackpad touch events are simply described under the
> @@ -530,7 +530,6 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  					dev_err(&client->dev,
>  						"Invalid input type: %u\n",
>  						val);
> -					fwnode_handle_put(ev_node);
>  					return -EINVAL;
>  				}
>  
> @@ -545,7 +544,6 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  				dev_err(&client->dev,
>  					"Invalid %s channel hysteresis: %u\n",
>  					fwnode_get_name(ch_node), val);
> -				fwnode_handle_put(ev_node);
>  				return -EINVAL;
>  			}
>  
> @@ -566,7 +564,6 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  				dev_err(&client->dev,
>  					"Invalid %s channel threshold: %u\n",
>  					fwnode_get_name(ch_node), val);
> -				fwnode_handle_put(ev_node);
>  				return -EINVAL;
>  			}
>  
> @@ -575,8 +572,6 @@ iqs626_parse_events(struct iqs626_private *iqs626,
>  			else
>  				*(thresh + iqs626_events[i].th_offs) = val;
>  		}
> -
> -		fwnode_handle_put(ev_node);
>  	}
>  
>  	return 0;
> @@ -774,12 +769,12 @@ static int iqs626_parse_trackpad(struct iqs626_private *iqs626,
>  	for (i = 0; i < iqs626_channels[ch_id].num_ch; i++) {
>  		u8 *ati_base = &sys_reg->tp_grp_reg.ch_reg_tp[i].ati_base;
>  		u8 *thresh = &sys_reg->tp_grp_reg.ch_reg_tp[i].thresh;
> -		struct fwnode_handle *tc_node;
>  		char tc_name[10];
>  
>  		snprintf(tc_name, sizeof(tc_name), "channel-%d", i);
>  
> -		tc_node = fwnode_get_named_child_node(ch_node, tc_name);
> +		struct fwnode_handle *tc_node __free(fwnode_handle) =
> +				fwnode_get_named_child_node(ch_node, tc_name);

Same here.

>  		if (!tc_node)
>  			continue;
>  
> @@ -790,7 +785,6 @@ static int iqs626_parse_trackpad(struct iqs626_private *iqs626,
>  				dev_err(&client->dev,
>  					"Invalid %s %s ATI base: %u\n",
>  					fwnode_get_name(ch_node), tc_name, val);
> -				fwnode_handle_put(tc_node);
>  				return -EINVAL;
>  			}
>  
> @@ -803,14 +797,11 @@ static int iqs626_parse_trackpad(struct iqs626_private *iqs626,
>  				dev_err(&client->dev,
>  					"Invalid %s %s threshold: %u\n",
>  					fwnode_get_name(ch_node), tc_name, val);
> -				fwnode_handle_put(tc_node);
>  				return -EINVAL;
>  			}
>  
>  			*thresh = val;
>  		}
> -
> -		fwnode_handle_put(tc_node);
>  	}
>  
>  	if (!fwnode_property_present(ch_node, "linux,keycodes"))
> @@ -1233,7 +1224,6 @@ static int iqs626_parse_prop(struct iqs626_private *iqs626)
>  {
>  	struct iqs626_sys_reg *sys_reg = &iqs626->sys_reg;
>  	struct i2c_client *client = iqs626->client;
> -	struct fwnode_handle *ch_node;
>  	unsigned int val;
>  	int error, i;
>  	u16 general;
> @@ -1375,13 +1365,13 @@ static int iqs626_parse_prop(struct iqs626_private *iqs626)
>  	sys_reg->active = 0;
>  
>  	for (i = 0; i < ARRAY_SIZE(iqs626_channels); i++) {
> -		ch_node = device_get_named_child_node(&client->dev,
> -						      iqs626_channels[i].name);
> +		struct fwnode_handle *ch_node __free(fwnode_handle) =
> +			device_get_named_child_node(&client->dev,
> +						    iqs626_channels[i].name);
>  		if (!ch_node)
>  			continue;
>  
>  		error = iqs626_parse_channel(iqs626, ch_node, i);
> -		fwnode_handle_put(ch_node);
>  		if (error)
>  			return error;
>  
> -- 
> 2.46.0.469.g59c65b2a67-goog
> 

Kind regards,
Jeff LaBundy