Revert "Revert "switch: switch class and GPIO drivers.""

[firefly-linux-kernel-4.4.55.git] / drivers / switch / switch_class.c

diff --git a/drivers/switch/switch_class.c b/drivers/switch/switch_class.c
new file mode 100644 (file)
index 0000000..e05fc25
--- /dev/null
+++ b/drivers/switch/switch_class.c
@@ -0,0 +1,174 @@
+/*
+ *  drivers/switch/switch_class.c
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+*/
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <linux/switch.h>
+
+struct class *switch_class;
+static atomic_t device_count;
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+               char *buf)
+{
+       struct switch_dev *sdev = (struct switch_dev *)
+               dev_get_drvdata(dev);
+
+       if (sdev->print_state) {
+               int ret = sdev->print_state(sdev, buf);
+               if (ret >= 0)
+                       return ret;
+       }
+       return sprintf(buf, "%d\n", sdev->state);
+}
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+               char *buf)
+{
+       struct switch_dev *sdev = (struct switch_dev *)
+               dev_get_drvdata(dev);
+
+       if (sdev->print_name) {
+               int ret = sdev->print_name(sdev, buf);
+               if (ret >= 0)
+                       return ret;
+       }
+       return sprintf(buf, "%s\n", sdev->name);
+}
+
+static DEVICE_ATTR(state, S_IRUGO | S_IWUSR, state_show, NULL);
+static DEVICE_ATTR(name, S_IRUGO | S_IWUSR, name_show, NULL);
+
+void switch_set_state(struct switch_dev *sdev, int state)
+{
+       char name_buf[120];
+       char state_buf[120];
+       char *prop_buf;
+       char *envp[3];
+       int env_offset = 0;
+       int length;
+
+       if (sdev->state != state) {
+               sdev->state = state;
+
+               prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
+               if (prop_buf) {
+                       length = name_show(sdev->dev, NULL, prop_buf);
+                       if (length > 0) {
+                               if (prop_buf[length - 1] == '\n')
+                                       prop_buf[length - 1] = 0;
+                               snprintf(name_buf, sizeof(name_buf),
+                                       "SWITCH_NAME=%s", prop_buf);
+                               envp[env_offset++] = name_buf;
+                       }
+                       length = state_show(sdev->dev, NULL, prop_buf);
+                       if (length > 0) {
+                               if (prop_buf[length - 1] == '\n')
+                                       prop_buf[length - 1] = 0;
+                               snprintf(state_buf, sizeof(state_buf),
+                                       "SWITCH_STATE=%s", prop_buf);
+                               envp[env_offset++] = state_buf;
+                       }
+                       envp[env_offset] = NULL;
+                       kobject_uevent_env(&sdev->dev->kobj, KOBJ_CHANGE, envp);
+                       free_page((unsigned long)prop_buf);
+               } else {
+                       printk(KERN_ERR "out of memory in switch_set_state\n");
+                       kobject_uevent(&sdev->dev->kobj, KOBJ_CHANGE);
+               }
+       }
+}
+EXPORT_SYMBOL_GPL(switch_set_state);
+
+static int create_switch_class(void)
+{
+       if (!switch_class) {
+               switch_class = class_create(THIS_MODULE, "switch");
+               if (IS_ERR(switch_class))
+                       return PTR_ERR(switch_class);
+               atomic_set(&device_count, 0);
+       }
+
+       return 0;
+}
+
+int switch_dev_register(struct switch_dev *sdev)
+{
+       int ret;
+
+       if (!switch_class) {
+               ret = create_switch_class();
+               if (ret < 0)
+                       return ret;
+       }
+
+       sdev->index = atomic_inc_return(&device_count);
+       sdev->dev = device_create(switch_class, NULL,
+               MKDEV(0, sdev->index), NULL, sdev->name);
+       if (IS_ERR(sdev->dev))
+               return PTR_ERR(sdev->dev);
+
+       ret = device_create_file(sdev->dev, &dev_attr_state);
+       if (ret < 0)
+               goto err_create_file_1;
+       ret = device_create_file(sdev->dev, &dev_attr_name);
+       if (ret < 0)
+               goto err_create_file_2;
+
+       dev_set_drvdata(sdev->dev, sdev);
+       sdev->state = 0;
+       return 0;
+
+err_create_file_2:
+       device_remove_file(sdev->dev, &dev_attr_state);
+err_create_file_1:
+       device_destroy(switch_class, MKDEV(0, sdev->index));
+       printk(KERN_ERR "switch: Failed to register driver %s\n", sdev->name);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(switch_dev_register);
+
+void switch_dev_unregister(struct switch_dev *sdev)
+{
+       device_remove_file(sdev->dev, &dev_attr_name);
+       device_remove_file(sdev->dev, &dev_attr_state);
+       device_destroy(switch_class, MKDEV(0, sdev->index));
+       dev_set_drvdata(sdev->dev, NULL);
+}
+EXPORT_SYMBOL_GPL(switch_dev_unregister);
+
+static int __init switch_class_init(void)
+{
+       return create_switch_class();
+}
+
+static void __exit switch_class_exit(void)
+{
+       class_destroy(switch_class);
+}
+
+module_init(switch_class_init);
+module_exit(switch_class_exit);
+
+MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
+MODULE_DESCRIPTION("Switch class driver");
+MODULE_LICENSE("GPL");