[PATCH][next] power: supply: cros_charge-control: Avoid -Wflex-array-member-not-at-end warning

[PATCH][next] power: supply: cros_charge-control: Avoid -Wflex-array-member-not-at-end warning

[Gustavo A. R. Silva]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of a
flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix the following warning:

drivers/power/supply/cros_charge-control.c:57:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/power/supply/cros_charge-control.c | 26 +++++++++-------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/power/supply/cros_charge-control.c b/drivers/power/supply/cros_charge-control.c
index 02d5bdbe2e8d..e33bc4c55bcc 100644
--- a/drivers/power/supply/cros_charge-control.c
+++ b/drivers/power/supply/cros_charge-control.c
@@ -53,23 +53,17 @@ static int cros_chctl_send_charge_control_cmd(struct cros_ec_device *cros_ec,
 		[3] = sizeof(struct ec_params_charge_control),
 	};
 
-	struct {
-		struct cros_ec_command msg;
-		union {
-			struct ec_params_charge_control req;
-			struct ec_response_charge_control resp;
-		} __packed data;
-	} __packed buf = {
-		.msg = {
-			.command = EC_CMD_CHARGE_CONTROL,
-			.version = cmd_version,
-			.insize  = 0,
-			.outsize = outsizes[cmd_version],
-		},
-		.data.req = *req,
-	};
+	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
+			MAX(sizeof(struct ec_params_charge_control),
+			    sizeof(struct ec_response_charge_control)));
+
+	msg->command = EC_CMD_CHARGE_CONTROL;
+	msg->version = cmd_version;
+	msg->insize  = 0;
+	msg->outsize = outsizes[cmd_version];
+	*(struct ec_params_charge_control *)msg->data = *req;
 
-	return cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
+	return cros_ec_cmd_xfer_status(cros_ec, msg);
 }
 
 static int cros_chctl_configure_ec(struct cros_chctl_priv *priv)
-- 
2.43.0

Re: [PATCH][next] power: supply: cros_charge-control: Avoid -Wflex-array-member-not-at-end warning

[Thomas Weißschuh]

On 2025-04-29 13:20:51-0600, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
> 
> Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of a
> flexible structure where the size of the flexible-array member
> is known at compile-time, and refactor the rest of the code,
> accordingly.
> 
> So, with these changes, fix the following warning:
> 
> drivers/power/supply/cros_charge-control.c:57:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/power/supply/cros_charge-control.c | 26 +++++++++-------------
>  1 file changed, 10 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/power/supply/cros_charge-control.c b/drivers/power/supply/cros_charge-control.c
> index 02d5bdbe2e8d..e33bc4c55bcc 100644
> --- a/drivers/power/supply/cros_charge-control.c
> +++ b/drivers/power/supply/cros_charge-control.c
> @@ -53,23 +53,17 @@ static int cros_chctl_send_charge_control_cmd(struct cros_ec_device *cros_ec,
>  		[3] = sizeof(struct ec_params_charge_control),
>  	};
>  
> -	struct {
> -		struct cros_ec_command msg;
> -		union {
> -			struct ec_params_charge_control req;
> -			struct ec_response_charge_control resp;
> -		} __packed data;
> -	} __packed buf = {
> -		.msg = {
> -			.command = EC_CMD_CHARGE_CONTROL,
> -			.version = cmd_version,
> -			.insize  = 0,
> -			.outsize = outsizes[cmd_version],
> -		},
> -		.data.req = *req,
> -	};
> +	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
> +			MAX(sizeof(struct ec_params_charge_control),
> +			    sizeof(struct ec_response_charge_control)));
> +
> +	msg->command = EC_CMD_CHARGE_CONTROL;
> +	msg->version = cmd_version;
> +	msg->insize  = 0;
> +	msg->outsize = outsizes[cmd_version];
> +	*(struct ec_params_charge_control *)msg->data = *req;

Please use cros_ec_cmd() like the LED driver.

https://lore.kernel.org/lkml/Z-rKcgFjsyKvd58q@kspp/

>  
> -	return cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
> +	return cros_ec_cmd_xfer_status(cros_ec, msg);
>  }
>  
>  static int cros_chctl_configure_ec(struct cros_chctl_priv *priv)
> -- 
> 2.43.0
>