[PATCH 11/23] gpio: mockup: remove the limit on number of dummy chips

[Bartosz Golaszewski <brgl@xxxxxxxx>]

From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

As a preparation for implementing dynamically created dummy GPIO chips:
drop the limit on the number of chips. Let's use a linked list to store
the chip context structures.

Let's rename gpio_mockup_unregister_pdevs() to
gpio_mockup_unregister_devices() as we're now handling structures in
which struct platform_device is embedded instead of operating on
platform devices directly.

Note: this does not remove the limit on the number of ranges passed as a
module parameter. For now nothing changes in how the module works for
user-space. This patch will however allow us to create a higher number
of chips once we can do this dynamically.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
 drivers/gpio/gpio-mockup.c | 59 ++++++++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index 19c092f814fd..801fba6496a4 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -13,6 +13,7 @@
 #include <linux/irq.h>
 #include <linux/irq_sim.h>
 #include <linux/irqdomain.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
@@ -24,12 +25,11 @@
 #undef pr_fmt
 #define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
 
-#define GPIO_MOCKUP_MAX_GC	10
 /*
  * We're storing two values per chip: the GPIO base and the number
  * of GPIO lines.
  */
-#define GPIO_MOCKUP_MAX_RANGES	(GPIO_MOCKUP_MAX_GC * 2)
+#define GPIO_MOCKUP_MAX_RANGES	(10 * 2)
 /* Maximum of three properties + the sentinel. */
 #define GPIO_MOCKUP_MAX_PROP	4
 
@@ -505,27 +505,37 @@ static struct platform_driver gpio_mockup_driver = {
 	.probe = gpio_mockup_probe,
 };
 
-static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
+struct gpio_mockup_device {
+	struct list_head list;
+	struct platform_device *pdev;
+};
 
-static void gpio_mockup_unregister_pdevs(void)
+static LIST_HEAD(gpio_mockup_devices);
+
+static void gpio_mockup_unregister_one_device(struct gpio_mockup_device *dev)
 {
-	struct platform_device *pdev;
-	int i;
+	list_del(&dev->list);
+	platform_device_unregister(dev->pdev);
+	kfree(dev);
+}
 
-	for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
-		pdev = gpio_mockup_pdevs[i];
+static void gpio_mockup_unregister_devices(void)
+{
+	struct gpio_mockup_device *mockup_dev;
+	struct list_head *curr, *next;
 
-		if (pdev)
-			platform_device_unregister(pdev);
+	list_for_each_safe(curr, next, &gpio_mockup_devices) {
+		mockup_dev = list_entry(curr, struct gpio_mockup_device, list);
+		gpio_mockup_unregister_one_device(mockup_dev);
 	}
 }
 
 static int __init gpio_mockup_init(void)
 {
 	struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
+	struct gpio_mockup_device *mockup_dev;
 	int i, prop, num_chips, err = 0, base;
 	struct platform_device_info pdevinfo;
-	struct platform_device *pdev;
 	u16 ngpio;
 
 	if ((gpio_mockup_num_ranges < 2) ||
@@ -576,26 +586,37 @@ static int __init gpio_mockup_init(void)
 		pdevinfo.id = i;
 		pdevinfo.properties = properties;
 
-		pdev = platform_device_register_full(&pdevinfo);
-		if (IS_ERR(pdev)) {
+		mockup_dev = kzalloc(sizeof(*mockup_dev), GFP_KERNEL);
+		if (!mockup_dev) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+
+		mockup_dev->pdev = platform_device_register_full(&pdevinfo);
+		if (IS_ERR(mockup_dev->pdev)) {
 			pr_err("error registering device");
-			platform_driver_unregister(&gpio_mockup_driver);
-			gpio_mockup_unregister_pdevs();
-			debugfs_remove_recursive(gpio_mockup_dbg_dir);
-			return PTR_ERR(pdev);
+			kfree(mockup_dev);
+			err = PTR_ERR(mockup_dev->pdev);
+			goto err_out;
 		}
 
-		gpio_mockup_pdevs[i] = pdev;
+		list_add(&mockup_dev->list, &gpio_mockup_devices);
 	}
 
 	return 0;
+
+err_out:
+	platform_driver_unregister(&gpio_mockup_driver);
+	gpio_mockup_unregister_devices();
+	debugfs_remove_recursive(gpio_mockup_dbg_dir);
+	return err;
 }
 
 static void __exit gpio_mockup_exit(void)
 {
 	debugfs_remove_recursive(gpio_mockup_dbg_dir);
 	platform_driver_unregister(&gpio_mockup_driver);
-	gpio_mockup_unregister_pdevs();
+	gpio_mockup_unregister_devices();
 }
 
 module_init(gpio_mockup_init);
-- 
2.26.1