mfd: cs5535-mfd: Request shared IO regions centrally

Prior to this patch, IO regions were requested via an MFD subsytem-level
.enable() call-back and similarly released by a .disable() call-back.
Double requests/releases were avoided by a centrally handled usage count
mechanism.

This complexity can all be avoided by handling IO regions only once during
.probe() and .remove() of the parent device.  Since this is the only
legitimate user of the aforementioned usage count mechanism, this patch
will allow it to be removed from MFD core in subsequent steps.
Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>

drivers/mfd/cs5535-mfd.c

@@ -27,38 +27,6 @@ enum cs5535_mfd_bars {
 	NR_BARS,
 };
 
-static int cs5535_mfd_res_enable(struct platform_device *pdev)
-{
-	struct resource *res;
-
-	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "can't fetch device resource info\n");
-		return -EIO;
-	}
-
-	if (!request_region(res->start, resource_size(res), DRV_NAME)) {
-		dev_err(&pdev->dev, "can't request region\n");
-		return -EIO;
-	}
-
-	return 0;
-}
-
-static int cs5535_mfd_res_disable(struct platform_device *pdev)
-{
-	struct resource *res;
-
-	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "can't fetch device resource info\n");
-		return -EIO;
-	}
-
-	release_region(res->start, resource_size(res));
-	return 0;
-}
-
 static struct resource cs5535_mfd_resources[NR_BARS];
 
 static struct mfd_cell cs5535_mfd_cells[] = {
@@ -81,17 +49,11 @@ static struct mfd_cell cs5535_mfd_cells[] = {
 		.name = "cs5535-pms",
 		.num_resources = 1,
 		.resources = &cs5535_mfd_resources[PMS_BAR],
-
-		.enable = cs5535_mfd_res_enable,
-		.disable = cs5535_mfd_res_disable,
 	},
 	{
 		.name = "cs5535-acpi",
 		.num_resources = 1,
 		.resources = &cs5535_mfd_resources[ACPI_BAR],
-
-		.enable = cs5535_mfd_res_enable,
-		.disable = cs5535_mfd_res_disable,
 	},
 };
 
@@ -117,22 +79,47 @@ static int cs5535_mfd_probe(struct pci_dev *pdev,
 		r->end = pci_resource_end(pdev, bar);
 	}
 
+	err = pci_request_region(pdev, PMS_BAR, DRV_NAME);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to request PMS_BAR's IO region\n");
+		goto err_disable;
+	}
+
 	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, cs5535_mfd_cells,
 			      ARRAY_SIZE(cs5535_mfd_cells), NULL, 0, NULL);
 	if (err) {
 		dev_err(&pdev->dev,
 			"Failed to add CS5535 sub-devices: %d\n", err);
-		goto err_disable;
+		goto err_release_pms;
 	}
 
-	if (machine_is_olpc())
-		mfd_clone_cell("cs5535-acpi", olpc_acpi_clones, ARRAY_SIZE(olpc_acpi_clones));
+	if (machine_is_olpc()) {
+		err = pci_request_region(pdev, ACPI_BAR, DRV_NAME);
+		if (err) {
+			dev_err(&pdev->dev,
+				"Failed to request ACPI_BAR's IO region\n");
+			goto err_remove_devices;
+		}
+
+		err = mfd_clone_cell("cs5535-acpi", olpc_acpi_clones,
+				     ARRAY_SIZE(olpc_acpi_clones));
+		if (err) {
+			dev_err(&pdev->dev, "Failed to clone MFD cell\n");
+			goto err_release_acpi;
+		}
+	}
 
 	dev_info(&pdev->dev, "%zu devices registered.\n",
 			ARRAY_SIZE(cs5535_mfd_cells));
 
 	return 0;
 
+err_release_acpi:
+	pci_release_region(pdev, ACPI_BAR);
+err_remove_devices:
+	mfd_remove_devices(&pdev->dev);
+err_release_pms:
+	pci_release_region(pdev, PMS_BAR);
 err_disable:
 	pci_disable_device(pdev);
 	return err;
@@ -141,6 +128,11 @@ static int cs5535_mfd_probe(struct pci_dev *pdev,
 static void cs5535_mfd_remove(struct pci_dev *pdev)
 {
 	mfd_remove_devices(&pdev->dev);
+
+	if (machine_is_olpc())
+		pci_release_region(pdev, ACPI_BAR);
+
+	pci_release_region(pdev, PMS_BAR);
 	pci_disable_device(pdev);
 }