ioc: Implement printer buffer handling in kernel driver
This commit is contained in:
parent
7a7399a602
commit
d588eeee42
@ -11,6 +11,7 @@
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#include <linux/uaccess.h>
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#include <linux/sched.h>
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#include <linux/poll.h>
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#include <linux/circ_buf.h>
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// #define ENABLE_DEBUG ENABLE_DEBUG
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@ -27,6 +28,11 @@ MODULE_PARM_DESC(debug_level, "Debug level");
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static struct serdev_device *static_serdev = NULL;
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static DECLARE_WAIT_QUEUE_HEAD(wq);
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void pbuf_work_handler(struct work_struct *work);
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DECLARE_WORK(pbuf_work, pbuf_work_handler);
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static DEFINE_SPINLOCK(printer_status_lock);
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static struct of_device_id lw35ioc_dt_ids[] = {
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{ .compatible = "brother,lw35", },
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{ /* sentinel */ }
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@ -37,7 +43,7 @@ MODULE_DEVICE_TABLE(of, lw35ioc_dt_ids);
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#define DEVICE_NAME "lw35"
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#define CLASS_NAME "lw35ioc"
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/* Only used for initialization, not for actualy keycode mapping */
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/* Only used for initialization, not for actual keycode mapping */
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static int keycode_map[] = {
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KEY_A, KEY_B, KEY_C, KEY_D, KEY_E, KEY_F, KEY_G, KEY_H, KEY_I, KEY_J,
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KEY_K, KEY_L, KEY_M, KEY_N, KEY_O, KEY_P, KEY_Q, KEY_R, KEY_S, KEY_T,
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@ -61,6 +67,7 @@ enum lw35ioc_packet_state {SYNC, TYPE, KEYBOARD, PRINTER};
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struct lw35ioc_packet {
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enum lw35ioc_packet_state state;
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int payload_offset;
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};
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struct lw35ioc_chardev {
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@ -70,7 +77,15 @@ struct lw35ioc_chardev {
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int open_count;
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};
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struct lw35ioc_printer_status{
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int buffer_free;
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int status;
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int reserved0;
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int reserved1;
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};
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#define UART_BUF_SIZE 256
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#define PBUF_SIZE 256
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struct lw35ioc_priv {
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struct serdev_device *serdev;
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@ -78,10 +93,17 @@ struct lw35ioc_priv {
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struct gpio_desc *gpio_rst; /* GPIO to reset both AVRs */
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struct lw35ioc_chardev chardev;
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struct lw35ioc_printer_status printer_status_temp;
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struct lw35ioc_printer_status printer_status;
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char uart_buf_rx[UART_BUF_SIZE];
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char *uart_buf_rx_rd;
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char *uart_buf_rx_wr;
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char pbuf[PBUF_SIZE];
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unsigned long pbuf_tail;
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unsigned long pbuf_head;
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enum lw35ioc_state state;
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struct lw35ioc_packet packet;
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};
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@ -95,6 +117,7 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
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unsigned char c;
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int ev;
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int i;
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unsigned long lock_flags;
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#ifdef ENABLE_DEBUG
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dev_info(&serdev->dev, "IRQ.\n");
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@ -109,6 +132,7 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
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if (c == 0xFF)
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priv->packet.state = TYPE;
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break;
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case TYPE:
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if (c == 0x55)
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priv->packet.state = KEYBOARD;
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@ -116,7 +140,9 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
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priv->packet.state = PRINTER;
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else
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priv->packet.state = SYNC;
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priv->packet.payload_offset = 0;
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break;
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case KEYBOARD:
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if (c > 127) {
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c -= 128;
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@ -128,10 +154,47 @@ static int lw35ioc_process_buf(struct serdev_device *serdev,
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input_sync(priv->input_dev);
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priv->packet.state = SYNC;
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break;
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case PRINTER:
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dev_info(&serdev->dev, "Printer not yet implemented.\n");
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switch (priv->packet.payload_offset) {
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case 0: /* Status */
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priv->printer_status_temp.status = (int)c;
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break;
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case 1: /* Buffer status */
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priv->printer_status_temp.buffer_free = (int)c;
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break;
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case 2: /* Reserved */
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priv->printer_status_temp.reserved0 = (int)c;
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break;
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case 3: /* Reserved */
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priv->printer_status_temp.reserved1 = (int)c;
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dev_info(&serdev->dev,
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"New printer status. status=0x%02X buffer_free=0x%02X [0x%02X,0x%02X].\n",
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priv->printer_status_temp.status,
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priv->printer_status_temp.buffer_free,
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priv->printer_status_temp.reserved0,
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priv->printer_status_temp.reserved1);
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if (priv->printer_status_temp.status == 0xFF) {
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dev_err(&serdev->dev,
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"HARDFAULT in printer firmware! Reset required.\n");
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}
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spin_lock_irqsave(&printer_status_lock, lock_flags);
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memcpy(&priv->printer_status,
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&priv->printer_status_temp,
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sizeof(priv->printer_status));
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spin_unlock_irqrestore(&printer_status_lock, lock_flags);
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if (priv->printer_status_temp.buffer_free > 0)
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schedule_work(&pbuf_work);
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priv->packet.state = SYNC;
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break;
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default:
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break;
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}
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priv->packet.payload_offset++;
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break;
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}
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}
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@ -145,9 +208,14 @@ static int lw35ioc_receive_buf(struct serdev_device *serdev,
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struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
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int i;
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if (priv->state == ACTIVE)
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switch (priv->state) {
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case ACTIVE:
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return lw35ioc_process_buf(serdev, data, count);
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break;
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case PASSIVE:
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break;
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default:
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/* Pass data directly to chardev */
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for (i = 0; i < count; ++i) {
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#ifdef ENABLE_DEBUG
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dev_info(&serdev->dev, " RX [PSV]: %02x\n", data[i]);
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@ -164,6 +232,7 @@ static int lw35ioc_receive_buf(struct serdev_device *serdev,
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}
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wake_up_interruptible(&wq);
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}
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return count; /* Pretend we read all data */
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}
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@ -205,32 +274,38 @@ static int lw35ioc_chardev_open(struct inode *inodep, struct file *filep) {
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if (!priv->chardev.open_count) {
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dev_info(&serdev->dev, "Opened chardev.\n");
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if (priv->state != ACTIVE &&
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priv->state != PASSIVE) {
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lw35ioc_reset_ioc_hw(serdev);
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switch (priv->state) {
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case PROG_KBD:
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lw35ioc_reset_ioc_hw(serdev);
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serdev_device_write(serdev, "X", 1, 0);
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dev_info(&serdev->dev, "Put ioc into programming mode: keyboard.\n");
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break;
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case PROG_PRI:
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lw35ioc_reset_ioc_hw(serdev);
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serdev_device_write(serdev, "Y", 1, 0);
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dev_info(&serdev->dev, "Put ioc into programming mode: printer.\n");
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break;
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case BYPASS:
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lw35ioc_reset_ioc_hw(serdev);
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serdev_device_write(serdev, "XX", 2, 0);
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dev_info(&serdev->dev, "Put ioc into bypass mode.\n");
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break;
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default:
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/* For other modes, we just wait for the reset to be over */
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case PASSIVE:
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lw35ioc_reset_ioc_hw(serdev);
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usleep_range(1000000, 1010000);
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dev_info(&serdev->dev, "Put ioc into active mode.\n");
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priv->state = ACTIVE;
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break;
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case ACTIVE:
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/* Don't do anything when active */
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break;
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default:
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break;
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}
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}
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} else {
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dev_err(&serdev->dev, "Rejected. Device may only be opened once.\n");
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//return -EBUSY;
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//return -EBUSY; // TODO
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}
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priv->chardev.open_count++;
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@ -251,7 +326,7 @@ static ssize_t lw35ioc_chardev_read(struct file *filep, char *buffer, size_t len
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wait_event_interruptible(wq, priv->uart_buf_rx_rd != priv->uart_buf_rx_wr);
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available = priv->uart_buf_rx_wr - priv->uart_buf_rx_rd;
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if (available < 0)
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available = 1;
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available = 1; /* TODO: We should calculate the remaining block until wraparound here... */
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if (!available)
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return -EAGAIN;
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}
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@ -279,12 +354,61 @@ char msg[256]; // TODO
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static ssize_t lw35ioc_chardev_write(struct file *filep, const char *buffer, size_t len, loff_t *offset) {
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struct serdev_device *serdev = filep->private_data;
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struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
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unsigned long tail;
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int i;
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int ret;
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switch (priv->state) {
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case ACTIVE:
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/* Put data into pbuf */
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// TODO: spinlock
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if (CIRC_SPACE(priv->pbuf_head, READ_ONCE(priv->pbuf_tail), PBUF_SIZE) < 1) {
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dev_err(&serdev->dev, "chdev write: Waiting for space...\n");
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if (ret = (wait_event_interruptible(wq, CIRC_SPACE(priv->pbuf_head, priv->pbuf_tail, PBUF_SIZE) >= 1))) { // TODO: Accessing pbuf_tail without any protection... this might be bad?
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dev_err(&serdev->dev,
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"chdev write: device closed while waiting. ret: %d\n",
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ret);
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// TODO: This is not proper handling of this I guess...
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return len;
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}
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dev_err(&serdev->dev, "chdev write: done waiting...\n");
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}
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tail = READ_ONCE(priv->pbuf_tail);
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for (i = 0; i < len; ++i) { // TODO: Block copy would be faster...
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if (CIRC_SPACE(priv->pbuf_head, tail, PBUF_SIZE) >= 1) {
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ret = copy_from_user(priv->pbuf + priv->pbuf_head,
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buffer + i,
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1);
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if (ret) {
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dev_err(&serdev->dev, "chdev write: copy_from_user failed (%d).\n",
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ret);
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i = len - 1;
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}
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smp_store_release(&(priv->pbuf_head),
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(priv->pbuf_head + 1) & (PBUF_SIZE - 1));
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} else {
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dev_warn(&serdev->dev, "chdev write: ring buffer full.\n");
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break;
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}
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}
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len = i;
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schedule_work(&pbuf_work);
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dev_info(&serdev->dev,
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"Copied %d bytes to FIFO (FIFO free: %d)",
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len, CIRC_SPACE(priv->pbuf_head, tail, PBUF_SIZE));
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break;
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case PASSIVE:
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len = -EBUSY; // TODO: Can I do this?
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break;
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default: /* Pass-through */
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if (len > 256) {
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len = 256;
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}
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copy_from_user(msg, buffer, len);
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copy_from_user(msg, buffer, len); // TODO: Return value
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serdev_device_write_buf(serdev, msg, len);
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}
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return len;
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}
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@ -337,6 +461,75 @@ __poll_t poll(struct file *filep, struct poll_table_struct *ptab)
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return 0;
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}
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#define PRINTER_READY_MASK (0b00011111)
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int printer_ready_for_data(struct lw35ioc_printer_status printer_status)
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{
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return ((printer_status.status & PRINTER_READY_MASK) == PRINTER_READY_MASK);
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}
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void pbuf_work_handler(struct work_struct *work)
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{
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// TODO: get private data using container_of(): https://linux-kernel-labs.github.io/master/labs/deferred_work.html
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struct serdev_device *serdev = static_serdev; // Not cool, but whatever...
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struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
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unsigned long head;
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unsigned long tail;
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unsigned long lock_flags;
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int bsize = 0;
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int i;
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int locked = 0;
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dev_info(&serdev->dev,
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"pbuf_work_handler\n");
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while (1) {
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// TODO: We are the only consumer, so we should be fine without a spinlock, right?
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head = smp_load_acquire(&priv->pbuf_head);
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tail = priv->pbuf_tail;
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bsize = CIRC_CNT(head, tail, PBUF_SIZE);
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dev_info(&serdev->dev, "CIRC CNT=%d\n", bsize);
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if (bsize == 0)
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break;
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spin_lock_irqsave(&printer_status_lock, lock_flags);
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locked = 1;
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if (!printer_ready_for_data(priv->printer_status)) {
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dev_warn(&serdev->dev, "Cannot transmit data to device. Device is not ready.\n");
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break;
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}
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if (bsize > priv->printer_status.buffer_free)
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bsize = priv->printer_status.buffer_free;
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if (bsize > CIRC_CNT_TO_END(head, tail, PBUF_SIZE))
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bsize = CIRC_CNT_TO_END(head, tail, PBUF_SIZE);
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if (bsize > priv->printer_status.buffer_free - 20)
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bsize = priv->printer_status.buffer_free - 20; // TODO: Bug workaround
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dev_info(&serdev->dev, "TX %d of %d bytes [%d bytes free on device].\n",
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bsize,
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CIRC_CNT(head, tail, PBUF_SIZE),
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priv->printer_status.buffer_free);
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priv->printer_status.buffer_free-=bsize;
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spin_unlock_irqrestore(&printer_status_lock, lock_flags);
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locked = 0;
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if (bsize == 0) {
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dev_warn(&serdev->dev, "Cannot transmit data to device. Device buffer is full.\n");
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break;
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}
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serdev_device_write_buf(serdev,
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priv->pbuf + tail,
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bsize);
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for (i=0; i<bsize; ++i) {
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dev_info(&serdev->dev,
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"UART TX: %c\n",
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priv->pbuf[tail + i]);
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}
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smp_store_release(&priv->pbuf_tail,
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(tail + bsize) & (PBUF_SIZE - 1));
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}
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if (locked)
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spin_unlock_irqrestore(&printer_status_lock, lock_flags);
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wake_up_interruptible(&wq); // There's some space available in the FIFO now, so wake up chardev write
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}
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static struct file_operations fops =
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@ -382,7 +575,7 @@ static int lw35ioc_cdev_init(struct serdev_device *serdev)
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return PTR_ERR(priv->chardev.device);
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}
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dev_err(&serdev->dev, "Device class created correctly\n");
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dev_info(&serdev->dev, "Device class created correctly\n");
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return 0;
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}
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@ -414,11 +607,16 @@ static int lw35ioc_probe(struct serdev_device *serdev)
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priv->uart_buf_rx_rd = priv->uart_buf_rx;
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priv->uart_buf_rx_wr = priv->uart_buf_rx;
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priv->pbuf_tail = 0;
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priv->pbuf_head = 0;
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priv->printer_status.buffer_free = 0;
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priv->printer_status.status = 0;
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priv->serdev = serdev;
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static_serdev = serdev;
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priv->packet.state = SYNC;
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serdev_device_set_drvdata(serdev, priv);
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serdev_device_set_client_ops(serdev, &lw35ioc_serdev_ops);
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/* Register input device */
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input_dev = devm_input_allocate_device(&serdev->dev);
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@ -440,12 +638,13 @@ static int lw35ioc_probe(struct serdev_device *serdev)
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goto fail_input;
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}
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serdev_device_set_client_ops(serdev, &lw35ioc_serdev_ops);
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ret = serdev_device_open(serdev);
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if (ret) {
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dev_err(&serdev->dev, "Unable to open device.\n");
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goto fail_serdev;
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}
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speed = serdev_device_set_baudrate(serdev, speed);
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dev_info(&serdev->dev, "Using baudrate: %u\n", speed);
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@ -486,17 +685,26 @@ static void lw35ioc_remove(struct serdev_device *serdev)
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{
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struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
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dev_info(&serdev->dev, "remove\n");
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dev_info(&serdev->dev, " cdev class: %p\n", priv->chardev.class);
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device_destroy(priv->chardev.class, MKDEV(priv->chardev.major_number, 0));
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dev_info(&serdev->dev, "unreg\n");
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class_unregister(priv->chardev.class);
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class_destroy(priv->chardev.class);
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dev_info(&serdev->dev, "destroy: SKIP\n");
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//class_destroy(priv->chardev.class);
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dev_info(&serdev->dev, "unreg-dev\n");
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unregister_chrdev(priv->chardev.major_number, DEVICE_NAME);
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dev_info(&serdev->dev, " gpio rst: %p\n", priv->gpio_rst);
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dev_info(&serdev->dev, " serdev: %p\n", priv->serdev);
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dev_info(&serdev->dev, " input dev: %p\n", priv->input_dev);
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lw35ioc_set_hw_reset(serdev, 1);
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gpiod_put(priv->gpio_rst);
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serdev_device_close(priv->serdev);
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input_unregister_device(priv->input_dev);
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|
||||
dev_info(&serdev->dev, "remove\n");
|
||||
dev_info(&serdev->dev, "done.\n");
|
||||
return;
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user