drivers/media/usb/rainshadow-cec/rainshadow-cec.c - linux - Git at Google

 /*
  * 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);
	/*
	* 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);