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