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Subject[PATCH 3/3] drm/bridge: it6505 driver add char device feature.
Date
From: Allen Chen <allen.chen@ite.com.tw>

This add can let us find it6505 char device in the /dev file and use read/write function to let the driver be hold.

Signed-off-by: Allen Chen <allen.chen@ite.com.tw>

---
drivers/gpu/drm/bridge/ite-it6505.c | 131 ++++++++++++++++++++++++++++++++++++
1 file changed, 131 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 13079a8..1529e61 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -70,6 +70,13 @@
/* if use this define will enable SHA debug */
/* #define SHA_DEBUG */

+/* register char device for it6505 */
+#define IT6505_CLASS_NAME "it6505_class"
+#define IT6505_DEVICE_NAME "it6505_device"
+#define IT6505_MAX_DEV 128
+/* The device major number */
+static int it6505_major_num;
+
enum sys_status {
SYS_UNPLUG = 0,
SYS_HPD,
@@ -144,6 +151,8 @@ struct it6505 {
struct it6505_platform_data pdata;
struct mutex lock;
struct regmap *regmap;
+ struct cdev cdev;
+ struct device class_dev;
struct it6505_dp_port *port;
/* thread sequence control */
struct semaphore sem_notifier;
@@ -2502,6 +2511,80 @@ static int it6505_init_pdata(struct it6505 *it6505)
return PTR_ERR_OR_ZERO(pdata->gpiod_reset);
}

+static int it6505_open(struct inode *inode, struct file *file)
+{
+ struct it6505 *ctx = container_of(inode->i_cdev, struct it6505, cdev);
+
+ DRM_DEBUG_DRIVER("[%s]: successful", __func__);
+ if (!ctx)
+ DRM_DEBUG_DRIVER("[%s]:get it6505 struct fail!", __func__);
+ file->private_data = ctx;
+ get_device(&ctx->class_dev);
+ return 0;
+}
+
+static int it6505_release(struct inode *inode, struct file *file)
+{
+ struct it6505 *ctx = file->private_data;
+
+ DRM_DEBUG_DRIVER("[%s]: successful", __func__);
+ put_device(&ctx->class_dev);
+ return 0;
+}
+
+static ssize_t it6505_read(struct file *file, char *buf,
+ size_t count, loff_t *ptr)
+{
+ struct it6505 *ctx = file->private_data;
+ char kbuff[16];
+ size_t len;
+
+ DRM_DEBUG_DRIVER("[%s]start count=%zu", __func__, count);
+ DRM_DEBUG_DRIVER("it6505_drv_hold:%d", ctx->it6505_drv_hold);
+ len = snprintf(kbuff, sizeof(kbuff), "%d", ctx->it6505_drv_hold);
+ len = min3(count, len, sizeof(kbuff));
+ return copy_to_user(buf, kbuff, len) ? -EFAULT : len;
+}
+
+static ssize_t it6505_write(struct file *file, const char *buff,
+ size_t count, loff_t *ptr)
+{
+ struct it6505 *ctx = file->private_data;
+ char kbuff[16];
+ int num;
+
+ DRM_DEBUG_DRIVER("[%s]start count=%zu", __func__, count);
+ count = min(count, sizeof(kbuff) - 1);
+ if (copy_from_user(kbuff, buff, count))
+ return -EFAULT;
+ kbuff[count] = '\0';
+ if (kstrtoint(kbuff, 10, &num) < 0)
+ return -EINVAL;
+ ctx->it6505_drv_hold = num;
+ DRM_DEBUG_DRIVER("set it6505_drv_hold:%d", ctx->it6505_drv_hold);
+ return count;
+}
+
+static struct class it6505_class_file = {
+ .owner = THIS_MODULE,
+ .name = IT6505_CLASS_NAME,
+};
+
+static const struct file_operations it6505_fops = {
+ .owner = THIS_MODULE,
+ .read = it6505_read,
+ .write = it6505_write,
+ .open = it6505_open,
+ .release = it6505_release
+};
+
+static void it6505_release_device(struct device *dev)
+{
+ struct it6505 *ctx = container_of(dev, struct it6505, class_dev);
+
+ kfree(ctx);
+}
+
static int it6505_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -2575,8 +2658,38 @@ static int it6505_i2c_probe(struct i2c_client *client,
ctx->bridge.funcs = &it6505_bridge_funcs;

drm_bridge_add(&ctx->bridge);
+ device_initialize(&ctx->class_dev);
+ ctx->class_dev.parent = &client->dev;
+ ctx->class_dev.release = it6505_release_device;
+ cdev_init(&ctx->cdev, &it6505_fops);
+ err = dev_set_name(&ctx->class_dev, "%s", IT6505_DEVICE_NAME);
+ DRM_DEBUG_DRIVER("[%s] dev_set_name:%s",
+ __func__, err ? "failed" : "success");
+ if (err) {
+ DRM_DEBUG_DRIVER("dev_set_name failed => %d", err);
+ goto put_class_dev;
+ }
+ /*
+ * Add the class device
+ * Link to the character device for creating the /dev entry
+ * in devtmpfs.
+ */
+ ctx->class_dev.devt = MKDEV(it6505_major_num, 0);
+ ctx->class_dev.class = &it6505_class_file;
+
+ /* We can now add the sysfs class, we know which parameter to show */
+ err = cdev_device_add(&ctx->cdev, &ctx->class_dev);
+ if (err) {
+ DRM_DEBUG_DRIVER("cdev_device_add failed => %d",
+ err);
+ goto put_class_dev;
+ }
DRM_DEBUG_DRIVER("[%s]end", __func__);
return 0;
+
+put_class_dev:
+ put_device(&ctx->class_dev);
+ return err;
}

static int it6505_remove(struct i2c_client *client)
@@ -2616,16 +2729,34 @@ struct i2c_driver it6505_i2c_driver = {

static int __init it6505_init(void)
{
+ int err;
+ dev_t dev = 0;
+
DRM_DEBUG_DRIVER("[%s]start", __func__);
+ /* Register the device class */
+ err = class_register(&it6505_class_file);
+ err = alloc_chrdev_region(&dev, 0, IT6505_MAX_DEV,
+ IT6505_DEVICE_NAME);
+ it6505_major_num = MAJOR(dev);
+ if (err < 0) {
+ DRM_DEBUG_DRIVER("alloc_chrdev_region() fail!");
+ goto failed_chrdevreg;
+ }
i2c_add_driver(&it6505_i2c_driver);
DRM_DEBUG_DRIVER("[%s]end", __func__);
return 0;
+
+failed_chrdevreg:
+ class_unregister(&it6505_class_file);
+ return err;
}

static void __exit it6505_exit(void)
{
DRM_DEBUG_DRIVER("[%s]start", __func__);
i2c_del_driver(&it6505_i2c_driver);
+ unregister_chrdev(it6505_major_num, IT6505_DEVICE_NAME);
+ class_unregister(&it6505_class_file);
DRM_DEBUG_DRIVER("[%s]end", __func__);
}

--
1.9.1
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