power: reset: pwr-mlxbf: support graceful shutdown

The OCP board used a BlueField's GPIO pin for entering
low power mode. That board was not commercialized and
has been dropped from production so all its code is unused.
The new hardware requirement is to trigger a graceful shutdown
when that GPIO pin is toggled. So replace the unused low power
mode with a graceful shutdown.
Signed-off-by: Asmaa Mnebhi <asmaa@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/20240611134327.30975-1-asmaa@nvidia.comSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/pwr-mlxbf.c

@@ -18,7 +18,6 @@
 
 struct pwr_mlxbf {
 	struct work_struct reboot_work;
-	struct work_struct shutdown_work;
 	const char *hid;
 };
 
@@ -27,22 +26,17 @@ static void pwr_mlxbf_reboot_work(struct work_struct *work)
 	acpi_bus_generate_netlink_event("button/reboot.*", "Reboot Button", 0x80, 1);
 }
 
-static void pwr_mlxbf_shutdown_work(struct work_struct *work)
-{
-	acpi_bus_generate_netlink_event("button/power.*", "Power Button", 0x80, 1);
-}
-
 static irqreturn_t pwr_mlxbf_irq(int irq, void *ptr)
 {
 	const char *rst_pwr_hid = "MLNXBF24";
-	const char *low_pwr_hid = "MLNXBF29";
+	const char *shutdown_hid = "MLNXBF29";
 	struct pwr_mlxbf *priv = ptr;
 
 	if (!strncmp(priv->hid, rst_pwr_hid, 8))
 		schedule_work(&priv->reboot_work);
 
-	if (!strncmp(priv->hid, low_pwr_hid, 8))
-		schedule_work(&priv->shutdown_work);
+	if (!strncmp(priv->hid, shutdown_hid, 8))
+		orderly_poweroff(true);
 
 	return IRQ_HANDLED;
 }
@@ -70,10 +64,6 @@ static int pwr_mlxbf_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return dev_err_probe(dev, irq, "Error getting %s irq.\n", priv->hid);
 
-	err = devm_work_autocancel(dev, &priv->shutdown_work, pwr_mlxbf_shutdown_work);
-	if (err)
-		return err;
-
 	err = devm_work_autocancel(dev, &priv->reboot_work, pwr_mlxbf_reboot_work);
 	if (err)
 		return err;