Re: [PATCH v3 5/7] drm/i2c: tda9950: add CEC driver

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On 04/20/2018 05:31 PM, Russell King - ARM Linux wrote:
> Hi Hans,
> 
> Any comments?

I have been traveling and haven't had time to look at this. Next week will
be busy as well, but I expect to be able to look at it the week after that.

I remember from the previous series that I couldn't test it with my BeagleBone
Black board (the calibration gpio had to switch from in to out but it wasn't allowed
since it had an associated irq). That's still a problem?

I didn't see any changes in that area when I did a quick scan.

Regards,

	Hans

> 
> Thanks.
> 
> On Mon, Apr 09, 2018 at 01:16:32PM +0100, Russell King wrote:
>> 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.
>>
>> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/i2c/Kconfig           |   5 +
>>  drivers/gpu/drm/i2c/Makefile          |   1 +
>>  drivers/gpu/drm/i2c/tda9950.c         | 509 ++++++++++++++++++++++++++++++++++
>>  include/linux/platform_data/tda9950.h |  16 ++
>>  4 files changed, 531 insertions(+)
>>  create mode 100644 drivers/gpu/drm/i2c/tda9950.c
>>  create mode 100644 include/linux/platform_data/tda9950.h
>>
>> diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
>> index a6c92beb410a..3a232f5ff0a1 100644
>> --- a/drivers/gpu/drm/i2c/Kconfig
>> +++ b/drivers/gpu/drm/i2c/Kconfig
>> @@ -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
>> diff --git a/drivers/gpu/drm/i2c/Makefile b/drivers/gpu/drm/i2c/Makefile
>> index b20100c18ffb..a962f6f08568 100644
>> --- a/drivers/gpu/drm/i2c/Makefile
>> +++ b/drivers/gpu/drm/i2c/Makefile
>> @@ -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
>> diff --git a/drivers/gpu/drm/i2c/tda9950.c b/drivers/gpu/drm/i2c/tda9950.c
>> new file mode 100644
>> index 000000000000..3f7396caad48
>> --- /dev/null
>> +++ b/drivers/gpu/drm/i2c/tda9950.c
>> @@ -0,0 +1,509 @@
>> +/*
>> + *  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@xxxxxxxxxxxxxxx>");
>> +MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/platform_data/tda9950.h b/include/linux/platform_data/tda9950.h
>> new file mode 100644
>> index 000000000000..c65efd461102
>> --- /dev/null
>> +++ b/include/linux/platform_data/tda9950.h
>> @@ -0,0 +1,16 @@
>> +#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
>> -- 
>> 2.7.4
>>
> 

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