Commit f0316f93 authored by Russell King's avatar Russell King
Browse files

drm/i2c: tda9950: add CEC driver 



Add a CEC driver for the TDA9950, which is a stand-alone I2C CEC device,
but is also integrated into HDMI transceivers such as the TDA9989 and
TDA19989.

The TDA9950 contains a command processor which handles retransmissions
and the low level bus protocol.  The driver just has to read and write
the messages, and handle error conditions.

Reviewed-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent ba8975f1

drivers/gpu/drm/i2c/Kconfig

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@@ -26,4 +26,9 @@ config DRM_I2C_NXP_TDA998X 
	help

	  Support for NXP Semiconductors TDA998X HDMI encoders.



config DRM_I2C_NXP_TDA9950

	tristate "NXP Semiconductors TDA9950/TDA998X HDMI CEC"

	select CEC_NOTIFIER

	select CEC_CORE



endmenu

drivers/gpu/drm/i2c/Makefile

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@@ -7,3 +7,4 @@ obj-$(CONFIG_DRM_I2C_SIL164) += sil164.o 


tda998x-y := tda998x_drv.o

obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o

obj-$(CONFIG_DRM_I2C_NXP_TDA9950) += tda9950.o

drivers/gpu/drm/i2c/tda9950.c

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/*

 *  TDA9950 Consumer Electronics Control driver

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * The NXP TDA9950 implements the HDMI Consumer Electronics Control

 * interface.  The host interface is similar to a mailbox: the data

 * registers starting at REG_CDR0 are written to send a command to the

 * internal CPU, and replies are read from these registers.

 *

 * As the data registers represent a mailbox, they must be accessed

 * as a single I2C transaction.  See the TDA9950 data sheet for details.

 */

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/platform_data/tda9950.h>

#include <linux/slab.h>

#include <drm/drm_edid.h>

#include <media/cec.h>

#include <media/cec-notifier.h>



enum {

	REG_CSR = 0x00,

	CSR_BUSY = BIT(7),

	CSR_INT  = BIT(6),

	CSR_ERR  = BIT(5),



	REG_CER = 0x01,



	REG_CVR = 0x02,



	REG_CCR = 0x03,

	CCR_RESET = BIT(7),

	CCR_ON    = BIT(6),



	REG_ACKH = 0x04,

	REG_ACKL = 0x05,



	REG_CCONR = 0x06,

	CCONR_ENABLE_ERROR = BIT(4),

	CCONR_RETRY_MASK = 7,



	REG_CDR0 = 0x07,



	CDR1_REQ = 0x00,

	CDR1_CNF = 0x01,

	CDR1_IND = 0x81,

	CDR1_ERR = 0x82,

	CDR1_IER = 0x83,



	CDR2_CNF_SUCCESS    = 0x00,

	CDR2_CNF_OFF_STATE  = 0x80,

	CDR2_CNF_BAD_REQ    = 0x81,

	CDR2_CNF_CEC_ACCESS = 0x82,

	CDR2_CNF_ARB_ERROR  = 0x83,

	CDR2_CNF_BAD_TIMING = 0x84,

	CDR2_CNF_NACK_ADDR  = 0x85,

	CDR2_CNF_NACK_DATA  = 0x86,

};



struct tda9950_priv {

	struct i2c_client *client;

	struct device *hdmi;

	struct cec_adapter *adap;

	struct tda9950_glue *glue;

	u16 addresses;

	struct cec_msg rx_msg;

	struct cec_notifier *notify;

	bool open;

};



static int tda9950_write_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)

{

	struct i2c_msg msg;

	u8 buf[cnt + 1];

	int ret;



	buf[0] = addr;

	memcpy(buf + 1, p, cnt);



	msg.addr = client->addr;

	msg.flags = 0;

	msg.len = cnt + 1;

	msg.buf = buf;



	dev_dbg(&client->dev, "wr 0x%02x: %*ph\n", addr, cnt, p);



	ret = i2c_transfer(client->adapter, &msg, 1);

	if (ret < 0)

		dev_err(&client->dev, "Error %d writing to cec:0x%x\n", ret, addr);

	return ret < 0 ? ret : 0;

}



static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)

{

	tda9950_write_range(client, addr, &val, 1);

}



static int tda9950_read_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)

{

	struct i2c_msg msg[2];

	int ret;



	msg[0].addr = client->addr;

	msg[0].flags = 0;

	msg[0].len = 1;

	msg[0].buf = &addr;

	msg[1].addr = client->addr;

	msg[1].flags = I2C_M_RD;

	msg[1].len = cnt;

	msg[1].buf = p;



	ret = i2c_transfer(client->adapter, msg, 2);

	if (ret < 0)

		dev_err(&client->dev, "Error %d reading from cec:0x%x\n", ret, addr);



	dev_dbg(&client->dev, "rd 0x%02x: %*ph\n", addr, cnt, p);



	return ret;

}



static u8 tda9950_read(struct i2c_client *client, u8 addr)

{

	int ret;

	u8 val;



	ret = tda9950_read_range(client, addr, &val, 1);

	if (ret < 0)

		val = 0;



	return val;

}



static irqreturn_t tda9950_irq(int irq, void *data)

{

	struct tda9950_priv *priv = data;

	unsigned int tx_status;

	u8 csr, cconr, buf[19];

	u8 arb_lost_cnt, nack_cnt, err_cnt;



	if (!priv->open)

		return IRQ_NONE;



	csr = tda9950_read(priv->client, REG_CSR);

	if (!(csr & CSR_INT))

		return IRQ_NONE;



	cconr = tda9950_read(priv->client, REG_CCONR) & CCONR_RETRY_MASK;



	tda9950_read_range(priv->client, REG_CDR0, buf, sizeof(buf));



	/*

	 * This should never happen: the data sheet says that there will

	 * always be a valid message if the interrupt line is asserted.

	 */

	if (buf[0] == 0) {

		dev_warn(&priv->client->dev, "interrupt pending, but no message?\n");

		return IRQ_NONE;

	}



	switch (buf[1]) {

	case CDR1_CNF: /* transmit result */

		arb_lost_cnt = nack_cnt = err_cnt = 0;

		switch (buf[2]) {

		case CDR2_CNF_SUCCESS:

			tx_status = CEC_TX_STATUS_OK;

			break;



		case CDR2_CNF_ARB_ERROR:

			tx_status = CEC_TX_STATUS_ARB_LOST;

			arb_lost_cnt = cconr;

			break;



		case CDR2_CNF_NACK_ADDR:

			tx_status = CEC_TX_STATUS_NACK;

			nack_cnt = cconr;

			break;



		default: /* some other error, refer to TDA9950 docs */

			dev_err(&priv->client->dev, "CNF reply error 0x%02x\n",

				buf[2]);

			tx_status = CEC_TX_STATUS_ERROR;

			err_cnt = cconr;

			break;

		}

		/* TDA9950 executes all retries for us */

		tx_status |= CEC_TX_STATUS_MAX_RETRIES;

		cec_transmit_done(priv->adap, tx_status, arb_lost_cnt,

				  nack_cnt, 0, err_cnt);

		break;



	case CDR1_IND:

		priv->rx_msg.len = buf[0] - 2;

		if (priv->rx_msg.len > CEC_MAX_MSG_SIZE)

			priv->rx_msg.len = CEC_MAX_MSG_SIZE;



		memcpy(priv->rx_msg.msg, buf + 2, priv->rx_msg.len);

		cec_received_msg(priv->adap, &priv->rx_msg);

		break;



	default: /* unknown */

		dev_err(&priv->client->dev, "unknown service id 0x%02x\n",

			buf[1]);

		break;

	}



	return IRQ_HANDLED;

}



static int tda9950_cec_transmit(struct cec_adapter *adap, u8 attempts,

				u32 signal_free_time, struct cec_msg *msg)

{

	struct tda9950_priv *priv = adap->priv;

	u8 buf[CEC_MAX_MSG_SIZE + 2];



	buf[0] = 2 + msg->len;

	buf[1] = CDR1_REQ;

	memcpy(buf + 2, msg->msg, msg->len);



	if (attempts > 5)

		attempts = 5;



	tda9950_write(priv->client, REG_CCONR, attempts);



	return tda9950_write_range(priv->client, REG_CDR0, buf, 2 + msg->len);

}



static int tda9950_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)

{

	struct tda9950_priv *priv = adap->priv;

	u16 addresses;

	u8 buf[2];



	if (addr == CEC_LOG_ADDR_INVALID)

		addresses = priv->addresses = 0;

	else

		addresses = priv->addresses |= BIT(addr);



	/* TDA9950 doesn't want address 15 set */

	addresses &= 0x7fff;

	buf[0] = addresses >> 8;

	buf[1] = addresses;



	return tda9950_write_range(priv->client, REG_ACKH, buf, 2);

}



/*

 * When operating as part of the TDA998x, we need additional handling

 * to initialise and shut down the TDA9950 part of the device.  These

 * two hooks are provided to allow the TDA998x code to perform those

 * activities.

 */

static int tda9950_glue_open(struct tda9950_priv *priv)

{

	int ret = 0;



	if (priv->glue && priv->glue->open)

		ret = priv->glue->open(priv->glue->data);



	priv->open = true;



	return ret;

}



static void tda9950_glue_release(struct tda9950_priv *priv)

{

	priv->open = false;



	if (priv->glue && priv->glue->release)

		priv->glue->release(priv->glue->data);

}



static int tda9950_open(struct tda9950_priv *priv)

{

	struct i2c_client *client = priv->client;

	int ret;



	ret = tda9950_glue_open(priv);

	if (ret)

		return ret;



	/* Reset the TDA9950, and wait 250ms for it to recover */

	tda9950_write(client, REG_CCR, CCR_RESET);

	msleep(250);



	tda9950_cec_adap_log_addr(priv->adap, CEC_LOG_ADDR_INVALID);



	/* Start the command processor */

	tda9950_write(client, REG_CCR, CCR_ON);



	return 0;

}



static void tda9950_release(struct tda9950_priv *priv)

{

	struct i2c_client *client = priv->client;

	int timeout = 50;

	u8 csr;



	/* Stop the command processor */

	tda9950_write(client, REG_CCR, 0);



	/* Wait up to .5s for it to signal non-busy */

	do {

		csr = tda9950_read(client, REG_CSR);

		if (!(csr & CSR_BUSY) || --timeout)

			break;

		msleep(10);

	} while (1);



	/* Warn the user that their IRQ may die if it's shared. */

	if (csr & CSR_BUSY)

		dev_warn(&client->dev, "command processor failed to stop, irq%d may die (csr=0x%02x)\n",

			 client->irq, csr);



	tda9950_glue_release(priv);

}



static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)

{

	struct tda9950_priv *priv = adap->priv;



	if (!enable) {

		tda9950_release(priv);

		return 0;

	} else {

		return tda9950_open(priv);

	}

}



static const struct cec_adap_ops tda9950_cec_ops = {

	.adap_enable = tda9950_cec_adap_enable,

	.adap_log_addr = tda9950_cec_adap_log_addr,

	.adap_transmit = tda9950_cec_transmit,

};



/*

 * When operating as part of the TDA998x, we need to claim additional

 * resources.  These two hooks permit the management of those resources.

 */

static void tda9950_devm_glue_exit(void *data)

{

	struct tda9950_glue *glue = data;



	if (glue && glue->exit)

		glue->exit(glue->data);

}



static int tda9950_devm_glue_init(struct device *dev, struct tda9950_glue *glue)

{

	int ret;



	if (glue && glue->init) {

		ret = glue->init(glue->data);

		if (ret)

			return ret;

	}



	ret = devm_add_action(dev, tda9950_devm_glue_exit, glue);

	if (ret)

		tda9950_devm_glue_exit(glue);



	return ret;

}



static void tda9950_cec_del(void *data)

{

	struct tda9950_priv *priv = data;



	cec_delete_adapter(priv->adap);

}



static int tda9950_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct tda9950_glue *glue = client->dev.platform_data;

	struct device *dev = &client->dev;

	struct tda9950_priv *priv;

	unsigned long irqflags;

	int ret;

	u8 cvr;



	/*

	 * We must have I2C functionality: our multi-byte accesses

	 * must be performed as a single contiguous transaction.

	 */

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

		dev_err(&client->dev,

			"adapter does not support I2C functionality\n");

		return -ENXIO;

	}



	/* We must have an interrupt to be functional. */

	if (client->irq <= 0) {

		dev_err(&client->dev, "driver requires an interrupt\n");

		return -ENXIO;

	}



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	priv->client = client;

	priv->glue = glue;



	i2c_set_clientdata(client, priv);



	/*

	 * If we're part of a TDA998x, we want the class devices to be

	 * associated with the HDMI Tx so we have a tight relationship

	 * between the HDMI interface and the CEC interface.

	 */

	priv->hdmi = dev;

	if (glue && glue->parent)

		priv->hdmi = glue->parent;



	priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",

					  CEC_CAP_DEFAULTS,

					  CEC_MAX_LOG_ADDRS);

	if (IS_ERR(priv->adap))

		return PTR_ERR(priv->adap);



	ret = devm_add_action(dev, tda9950_cec_del, priv);

	if (ret) {

		cec_delete_adapter(priv->adap);

		return ret;

	}



	ret = tda9950_devm_glue_init(dev, glue);

	if (ret)

		return ret;



	ret = tda9950_glue_open(priv);

	if (ret)

		return ret;



	cvr = tda9950_read(client, REG_CVR);



	dev_info(&client->dev,

		 "TDA9950 CEC interface, hardware version %u.%u\n",

		 cvr >> 4, cvr & 15);



	tda9950_glue_release(priv);



	irqflags = IRQF_TRIGGER_FALLING;

	if (glue)

		irqflags = glue->irq_flags;



	ret = devm_request_threaded_irq(dev, client->irq, NULL, tda9950_irq,

					irqflags | IRQF_SHARED | IRQF_ONESHOT,

					dev_name(&client->dev), priv);

	if (ret < 0)

		return ret;



	priv->notify = cec_notifier_get(priv->hdmi);

	if (!priv->notify)

		return -ENOMEM;



	ret = cec_register_adapter(priv->adap, priv->hdmi);

	if (ret < 0) {

		cec_notifier_put(priv->notify);

		return ret;

	}



	/*

	 * CEC documentation says we must not call cec_delete_adapter

	 * after a successful call to cec_register_adapter().

	 */

	devm_remove_action(dev, tda9950_cec_del, priv);



	cec_register_cec_notifier(priv->adap, priv->notify);



	return 0;

}



static int tda9950_remove(struct i2c_client *client)

{

	struct tda9950_priv *priv = i2c_get_clientdata(client);



	cec_unregister_adapter(priv->adap);

	cec_notifier_put(priv->notify);



	return 0;

}



static struct i2c_device_id tda9950_ids[] = {

	{ "tda9950", 0 },

	{ },

};

MODULE_DEVICE_TABLE(i2c, tda9950_ids);



static struct i2c_driver tda9950_driver = {

	.probe = tda9950_probe,

	.remove = tda9950_remove,

	.driver = {

		.name = "tda9950",

	},

	.id_table = tda9950_ids,

};



module_i2c_driver(tda9950_driver);



MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");

MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");

MODULE_LICENSE("GPL v2");

include/linux/platform_data/tda9950.h

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#ifndef LINUX_PLATFORM_DATA_TDA9950_H

#define LINUX_PLATFORM_DATA_TDA9950_H



struct device;



struct tda9950_glue {

	struct device *parent;

	unsigned long irq_flags;

	void *data;

	int (*init)(void *);

	void (*exit)(void *);

	int (*open)(void *);

	void (*release)(void *);

};



#endif

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