386 lines
8.6 KiB
C
386 lines
8.6 KiB
C
/*
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* RainShadow Tech HDMI CEC driver
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*
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* Copyright 2016 Hans Verkuil <hverkuil@xs4all.nl
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version of 2 of the License, or (at your
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* option) any later version. See the file COPYING in the main directory of
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* this archive for more details.
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*/
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/*
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* Notes:
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*
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* The higher level protocols are currently disabled. This can be added
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* later, similar to how this is done for the Pulse Eight CEC driver.
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*
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* Documentation of the protocol is available here:
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*
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* http://rainshadowtech.com/doc/HDMICECtoUSBandRS232v2.0.pdf
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*/
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#include <linux/completion.h>
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#include <linux/ctype.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/serio.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/time.h>
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#include <linux/workqueue.h>
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#include <media/cec.h>
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MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
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MODULE_DESCRIPTION("RainShadow Tech HDMI CEC driver");
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MODULE_LICENSE("GPL");
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#define DATA_SIZE 256
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struct rain {
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struct device *dev;
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struct serio *serio;
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struct cec_adapter *adap;
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struct completion cmd_done;
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struct work_struct work;
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/* Low-level ringbuffer, collecting incoming characters */
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char buf[DATA_SIZE];
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unsigned int buf_rd_idx;
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unsigned int buf_wr_idx;
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unsigned int buf_len;
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spinlock_t buf_lock;
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/* command buffer */
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char cmd[DATA_SIZE];
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unsigned int cmd_idx;
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bool cmd_started;
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/* reply to a command, only used to store the firmware version */
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char cmd_reply[DATA_SIZE];
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struct mutex write_lock;
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};
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static void rain_process_msg(struct rain *rain)
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{
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struct cec_msg msg = {};
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const char *cmd = rain->cmd + 3;
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int stat = -1;
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for (; *cmd; cmd++) {
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if (!isxdigit(*cmd))
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continue;
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if (isxdigit(cmd[0]) && isxdigit(cmd[1])) {
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if (msg.len == CEC_MAX_MSG_SIZE)
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break;
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if (hex2bin(msg.msg + msg.len, cmd, 1))
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continue;
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msg.len++;
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cmd++;
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continue;
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}
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if (!cmd[1])
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stat = hex_to_bin(cmd[0]);
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break;
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}
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if (rain->cmd[0] == 'R') {
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if (stat == 1 || stat == 2)
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cec_received_msg(rain->adap, &msg);
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return;
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}
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switch (stat) {
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case 1:
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cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_OK);
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break;
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case 2:
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cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_NACK);
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break;
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default:
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cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_LOW_DRIVE);
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break;
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}
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}
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static void rain_irq_work_handler(struct work_struct *work)
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{
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struct rain *rain =
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container_of(work, struct rain, work);
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while (true) {
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unsigned long flags;
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char data;
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spin_lock_irqsave(&rain->buf_lock, flags);
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if (!rain->buf_len) {
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spin_unlock_irqrestore(&rain->buf_lock, flags);
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break;
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}
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data = rain->buf[rain->buf_rd_idx];
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rain->buf_len--;
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rain->buf_rd_idx = (rain->buf_rd_idx + 1) & 0xff;
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spin_unlock_irqrestore(&rain->buf_lock, flags);
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if (!rain->cmd_started && data != '?')
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continue;
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switch (data) {
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case '\r':
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rain->cmd[rain->cmd_idx] = '\0';
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dev_dbg(rain->dev, "received: %s\n", rain->cmd);
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if (!memcmp(rain->cmd, "REC", 3) ||
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!memcmp(rain->cmd, "STA", 3)) {
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rain_process_msg(rain);
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} else {
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strscpy(rain->cmd_reply, rain->cmd,
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sizeof(rain->cmd_reply));
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complete(&rain->cmd_done);
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}
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rain->cmd_idx = 0;
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rain->cmd_started = false;
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break;
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case '\n':
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rain->cmd_idx = 0;
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rain->cmd_started = false;
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break;
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case '?':
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rain->cmd_idx = 0;
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rain->cmd_started = true;
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break;
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default:
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if (rain->cmd_idx >= DATA_SIZE - 1) {
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dev_dbg(rain->dev,
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"throwing away %d bytes of garbage\n", rain->cmd_idx);
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rain->cmd_idx = 0;
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}
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rain->cmd[rain->cmd_idx++] = data;
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break;
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}
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}
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}
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static irqreturn_t rain_interrupt(struct serio *serio, unsigned char data,
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unsigned int flags)
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{
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struct rain *rain = serio_get_drvdata(serio);
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if (rain->buf_len == DATA_SIZE) {
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dev_warn_once(rain->dev, "buffer overflow\n");
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return IRQ_HANDLED;
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}
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spin_lock(&rain->buf_lock);
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rain->buf_len++;
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rain->buf[rain->buf_wr_idx] = data;
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rain->buf_wr_idx = (rain->buf_wr_idx + 1) & 0xff;
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spin_unlock(&rain->buf_lock);
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schedule_work(&rain->work);
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return IRQ_HANDLED;
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}
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static void rain_disconnect(struct serio *serio)
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{
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struct rain *rain = serio_get_drvdata(serio);
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cancel_work_sync(&rain->work);
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cec_unregister_adapter(rain->adap);
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dev_info(&serio->dev, "disconnected\n");
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serio_close(serio);
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serio_set_drvdata(serio, NULL);
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kfree(rain);
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}
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static int rain_send(struct rain *rain, const char *command)
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{
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int err = serio_write(rain->serio, '!');
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dev_dbg(rain->dev, "send: %s\n", command);
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while (!err && *command)
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err = serio_write(rain->serio, *command++);
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if (!err)
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err = serio_write(rain->serio, '~');
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return err;
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}
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static int rain_send_and_wait(struct rain *rain,
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const char *cmd, const char *reply)
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{
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int err;
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init_completion(&rain->cmd_done);
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mutex_lock(&rain->write_lock);
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err = rain_send(rain, cmd);
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if (err)
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goto err;
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if (!wait_for_completion_timeout(&rain->cmd_done, HZ)) {
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err = -ETIMEDOUT;
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goto err;
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}
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if (reply && strncmp(rain->cmd_reply, reply, strlen(reply))) {
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dev_dbg(rain->dev,
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"transmit of '%s': received '%s' instead of '%s'\n",
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cmd, rain->cmd_reply, reply);
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err = -EIO;
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}
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err:
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mutex_unlock(&rain->write_lock);
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return err;
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}
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static int rain_setup(struct rain *rain, struct serio *serio,
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struct cec_log_addrs *log_addrs, u16 *pa)
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{
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int err;
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err = rain_send_and_wait(rain, "R", "REV");
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if (err)
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return err;
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dev_info(rain->dev, "Firmware version %s\n", rain->cmd_reply + 4);
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err = rain_send_and_wait(rain, "Q 1", "QTY");
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if (err)
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return err;
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err = rain_send_and_wait(rain, "c0000", "CFG");
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if (err)
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return err;
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return rain_send_and_wait(rain, "A F 0000", "ADR");
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}
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static int rain_cec_adap_enable(struct cec_adapter *adap, bool enable)
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{
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return 0;
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}
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static int rain_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
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{
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struct rain *rain = cec_get_drvdata(adap);
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u8 cmd[16];
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if (log_addr == CEC_LOG_ADDR_INVALID)
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log_addr = CEC_LOG_ADDR_UNREGISTERED;
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snprintf(cmd, sizeof(cmd), "A %x", log_addr);
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return rain_send_and_wait(rain, cmd, "ADR");
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}
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static int rain_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
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u32 signal_free_time, struct cec_msg *msg)
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{
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struct rain *rain = cec_get_drvdata(adap);
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char cmd[2 * CEC_MAX_MSG_SIZE + 16];
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unsigned int i;
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int err;
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if (msg->len == 1) {
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snprintf(cmd, sizeof(cmd), "x%x", cec_msg_destination(msg));
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} else {
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char hex[3];
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snprintf(cmd, sizeof(cmd), "x%x %02x ",
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cec_msg_destination(msg), msg->msg[1]);
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for (i = 2; i < msg->len; i++) {
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snprintf(hex, sizeof(hex), "%02x", msg->msg[i]);
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strlcat(cmd, hex, sizeof(cmd));
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}
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}
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mutex_lock(&rain->write_lock);
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err = rain_send(rain, cmd);
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mutex_unlock(&rain->write_lock);
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return err;
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}
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static const struct cec_adap_ops rain_cec_adap_ops = {
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.adap_enable = rain_cec_adap_enable,
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.adap_log_addr = rain_cec_adap_log_addr,
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.adap_transmit = rain_cec_adap_transmit,
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};
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static int rain_connect(struct serio *serio, struct serio_driver *drv)
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{
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u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR | CEC_CAP_MONITOR_ALL;
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struct rain *rain;
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int err = -ENOMEM;
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struct cec_log_addrs log_addrs = {};
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u16 pa = CEC_PHYS_ADDR_INVALID;
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rain = kzalloc(sizeof(*rain), GFP_KERNEL);
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if (!rain)
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return -ENOMEM;
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rain->serio = serio;
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rain->adap = cec_allocate_adapter(&rain_cec_adap_ops, rain,
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dev_name(&serio->dev), caps, 1);
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err = PTR_ERR_OR_ZERO(rain->adap);
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if (err < 0)
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goto free_device;
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rain->dev = &serio->dev;
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serio_set_drvdata(serio, rain);
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INIT_WORK(&rain->work, rain_irq_work_handler);
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mutex_init(&rain->write_lock);
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spin_lock_init(&rain->buf_lock);
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err = serio_open(serio, drv);
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if (err)
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goto delete_adap;
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err = rain_setup(rain, serio, &log_addrs, &pa);
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if (err)
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goto close_serio;
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err = cec_register_adapter(rain->adap, &serio->dev);
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if (err < 0)
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goto close_serio;
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rain->dev = &rain->adap->devnode.dev;
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return 0;
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close_serio:
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serio_close(serio);
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delete_adap:
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cec_delete_adapter(rain->adap);
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serio_set_drvdata(serio, NULL);
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free_device:
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kfree(rain);
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return err;
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}
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static const struct serio_device_id rain_serio_ids[] = {
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{
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.type = SERIO_RS232,
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.proto = SERIO_RAINSHADOW_CEC,
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.id = SERIO_ANY,
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.extra = SERIO_ANY,
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},
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{ 0 }
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};
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MODULE_DEVICE_TABLE(serio, rain_serio_ids);
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static struct serio_driver rain_drv = {
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.driver = {
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.name = "rainshadow-cec",
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},
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.description = "RainShadow Tech HDMI CEC driver",
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.id_table = rain_serio_ids,
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.interrupt = rain_interrupt,
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.connect = rain_connect,
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.disconnect = rain_disconnect,
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};
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module_serio_driver(rain_drv);
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