ioc: kernel-driver: Add IOC charecter device
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101117d0bc
commit
6e1a771862
@ -8,6 +8,9 @@
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#include <linux/types.h>
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#include <linux/input.h>
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#include <linux/gpio/consumer.h>
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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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// #define ENABLE_DEBUG ENABLE_DEBUG
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@ -20,12 +23,20 @@ static int debug_level = 0;
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module_param(debug_level, int, 0);
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MODULE_PARM_DESC(debug_level, "Debug level");
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/* Only for chrdev... man they really suck! */
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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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static struct of_device_id lw35ioc_dt_ids[] = {
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{ .compatible = "brother,lw35", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, lw35ioc_dt_ids);
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/* Chardev */
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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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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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@ -44,7 +55,7 @@ static int keycode_map[] = {
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KEY_SYSRQ
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};
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enum lw35ioc_state {PASSIVE, PASSTHROUGH, ACTIVE};
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enum lw35ioc_state {PASSIVE = 0, PROG_KBD, PROG_PRI, BYPASS, ACTIVE, STATE_COUNT};
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enum lw35ioc_packet_state {SYNC, TYPE, KEYBOARD, PRINTER};
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@ -52,11 +63,25 @@ struct lw35ioc_packet {
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enum lw35ioc_packet_state state;
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};
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struct lw35ioc_chardev {
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int major_number;
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struct class* class;
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struct device* device;
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int open_count;
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};
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#define UART_BUF_SIZE 256
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struct lw35ioc_priv {
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struct serdev_device *serdev;
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struct input_dev *input_dev;
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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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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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enum lw35ioc_state state;
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struct lw35ioc_packet packet;
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};
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@ -118,15 +143,33 @@ static int lw35ioc_receive_buf(struct serdev_device *serdev,
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size_t count)
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{
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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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return lw35ioc_process_buf(serdev, data, count);
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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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#endif
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*(priv->uart_buf_rx_wr) = data[i];
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if (priv->uart_buf_rx_wr == priv->uart_buf_rx + UART_BUF_SIZE - 1)
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priv->uart_buf_rx_wr = priv->uart_buf_rx;
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else
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priv->uart_buf_rx_wr++;
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if (priv->uart_buf_rx_rd == priv->uart_buf_rx_wr) {
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dev_err(&serdev->dev, "UART RX buffer overflow.\n");
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}
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}
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wake_up_interruptible(&wq);
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return count; /* Pretend we read all data */
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}
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static void lw35ioc_write_wakeup(struct serdev_device *serdev)
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{
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dev_info(&serdev->dev, "Write wakeup\n");
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// schedule work here
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}
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@ -140,19 +183,224 @@ static void lw35ioc_set_hw_reset(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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gpiod_set_value(priv->gpio_rst, !reset_active);
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gpiod_set_value(priv->gpio_rst, !!reset_active);
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}
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static void lw35ioc_reset_ioc_hw(struct serdev_device *serdev)
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{
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dev_info(&serdev->dev, "Resetting IOC...\n");
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lw35ioc_set_hw_reset(serdev, 1);
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usleep_range(90000, 100000);
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lw35ioc_set_hw_reset(serdev, 0);
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usleep_range(90000, 100000);
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}
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/* Chardev */
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static int lw35ioc_chardev_open(struct inode *inodep, struct file *filep) {
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struct serdev_device *serdev = static_serdev;
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struct lw35ioc_priv *priv = serdev_device_get_drvdata(serdev);
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filep->private_data = serdev;
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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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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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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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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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usleep_range(1000000, 1010000);
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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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}
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priv->chardev.open_count++;
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return 0;
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}
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static ssize_t lw35ioc_chardev_read(struct file *filep, 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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int error_count;
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int available;
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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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if (!available) { /* Wait for data to become available */
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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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if (!available)
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return -EAGAIN;
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}
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if (available < len)
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len = available;
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error_count = copy_to_user(buffer, priv->uart_buf_rx_rd, len);
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len -= error_count;
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priv->uart_buf_rx_rd += len;
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if (priv->uart_buf_rx_rd >= priv->uart_buf_rx + UART_BUF_SIZE) {
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priv->uart_buf_rx_rd -= UART_BUF_SIZE;
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}
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if (error_count == 0) {
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return len;
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} else {
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dev_err(&serdev->dev, "Failed to read %d characters to chardev.\n",
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error_count);
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return -EFAULT;
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}
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}
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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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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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serdev_device_write_buf(serdev, msg, len);
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return len;
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}
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static int lw35ioc_chardev_release(struct inode *inodep, struct file *filep){
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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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priv->chardev.open_count--;
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dev_info(&serdev->dev, "Device successfully closed\n");
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return 0;
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}
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#define IOCTL_SET_MODE 42
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static long lw35ioc_chardev_ioctl(struct file *filep, unsigned int cmd,
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unsigned long arg)
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{
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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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switch (cmd) {
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case IOCTL_SET_MODE:
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if (arg >= STATE_COUNT || arg < 0) {
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dev_err(&serdev->dev, "Invalid driver mode: %lu", arg);
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return -1;
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}
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priv->state = arg;
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dev_info(&serdev->dev, "Switched driver mode to: %lu. Will be applied with next open().\n", arg);
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break;
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default:
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dev_info(&serdev->dev, "Ignoring IOCTL %u(%lu)\n", cmd, arg);
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break;
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}
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return 0;
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}
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__poll_t poll(struct file *filep, struct poll_table_struct *ptab)
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{
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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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poll_wait(filep, &wq, ptab);
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if (priv->uart_buf_rx_wr != priv->uart_buf_rx_rd)
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return EPOLLIN | EPOLLRDNORM;
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return 0;
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}
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static struct file_operations fops =
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{
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.open = lw35ioc_chardev_open,
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.read = lw35ioc_chardev_read,
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.write = lw35ioc_chardev_write,
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.release = lw35ioc_chardev_release,
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.unlocked_ioctl = lw35ioc_chardev_ioctl,
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.poll = poll,
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};
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static int lw35ioc_cdev_init(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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priv->chardev.open_count = 0;
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// Try to dynamically allocate a major number for the device
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priv->chardev.major_number = register_chrdev(0, DEVICE_NAME, &fops);
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if (priv->chardev.major_number < 0) {
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dev_err(&serdev->dev, "Failed to register a major number\n");
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return priv->chardev.major_number;
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}
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dev_info(&serdev->dev, "Registered correctly with major number %d\n", priv->chardev.major_number);
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// Register the device class
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priv->chardev.class = class_create(THIS_MODULE, CLASS_NAME);
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if (IS_ERR(priv->chardev.class)) {
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unregister_chrdev(priv->chardev.major_number, DEVICE_NAME);
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dev_err(&serdev->dev, "Failed to register device class\n");
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return PTR_ERR(priv->chardev.class);
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}
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dev_info(&serdev->dev, "Device class registered correctly\n");
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// Register the device driver
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priv->chardev.device = device_create(priv->chardev.class, NULL, MKDEV(priv->chardev.major_number, 0), NULL, DEVICE_NAME);
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if (IS_ERR(priv->chardev.device)) {
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class_destroy(priv->chardev.class);
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unregister_chrdev(priv->chardev.major_number, DEVICE_NAME);
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dev_err(&serdev->dev, "Failed to create the device\n");
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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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return 0;
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}
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static int lw35ioc_probe(struct serdev_device *serdev)
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{
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struct lw35ioc_priv *priv = NULL;
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int ret;
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int ret = 0;
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int i;
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u32 speed = 19200;
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struct input_dev *input_dev;
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printk(KERN_INFO "lw35ioc: probe\n");
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if (static_serdev) {
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printk(KERN_ERR "lw35ioc: Can only be loaded once.\n");
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goto fail_multicheck;
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}
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/* Allocate memory */
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priv = devm_kzalloc(&serdev->dev,
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sizeof(struct lw35ioc_priv),
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@ -161,8 +409,13 @@ static int lw35ioc_probe(struct serdev_device *serdev)
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printk(KERN_ERR "lw35ioc: Not enough memory.\n");
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return -ENOMEM;
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}
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priv->state = PASSIVE;
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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->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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@ -200,14 +453,23 @@ static int lw35ioc_probe(struct serdev_device *serdev)
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priv->gpio_rst = gpiod_get_index(&serdev->dev,
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"rst",
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0,
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GPIOD_OUT_LOW);
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lw35ioc_set_hw_reset(serdev, 0);
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GPIOD_OUT_HIGH);
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/* Register character device */
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ret = lw35ioc_cdev_init(serdev);
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if (ret) {
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dev_err(&serdev->dev, "Unable to initialize character device.\n");
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goto fail_gpio;
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}
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if (IS_ERR(priv->gpio_rst)) {
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dev_err(&serdev->dev, "Unable to get reset GPIO.\n");
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ret = -ENODEV;
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ret = -ENODEV; /* TODO */
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goto fail_gpio;
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}
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lw35ioc_reset_ioc_hw(serdev);
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dev_info(&serdev->dev, "Loaded driver.\n");
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return 0;
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@ -216,6 +478,7 @@ fail_serdev:
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input_unregister_device(input_dev);
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fail_input:
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devm_kfree(&serdev->dev, input_dev);
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fail_multicheck:
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return ret;
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}
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@ -223,6 +486,11 @@ 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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device_destroy(priv->chardev.class, MKDEV(priv->chardev.major_number, 0));
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class_unregister(priv->chardev.class);
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class_destroy(priv->chardev.class);
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unregister_chrdev(priv->chardev.major_number, DEVICE_NAME);
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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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@ -243,4 +511,3 @@ static struct serdev_device_driver lw35ioc_driver = {
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};
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module_serdev_device_driver(lw35ioc_driver);
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