Re: [PATCH v5 2/2] media: cec: i2c: ch7322: Add ch7322 CEC controller driver

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Hi Jeff,

I realized that there is one thing missing here: there is no way to
associate this CEC device with the corresponding HDMI interface.

Typically this is done either via the device tree (hdmi-phandle property,
see cec_notifier_parse_hdmi_phandle()) or ACPI (see cros-ec or seco drivers).

How is this ch7322 used? Chromebooks? Intel or ARM based?

The link with the HDMI interface is needed for the CEC_ADAP_G_CONNECTOR_INFO
ioctl implementation. See:

https://hverkuil.home.xs4all.nl/spec/userspace-api/cec/cec-ioc-adap-g-conn-info.html

Regards,

	Hans

On 15/06/2020 21:38, Jeff Chase wrote:
> Add a CEC device driver for the Chrontel ch7322 CEC conroller.
> This is an I2C device capable of sending and receiving CEC messages.
> 
> Signed-off-by: Jeff Chase <jnchase@xxxxxxxxxx>
> ---
>  MAINTAINERS                    |   1 +
>  drivers/media/cec/Kconfig      |   1 +
>  drivers/media/cec/Makefile     |   2 +-
>  drivers/media/cec/i2c/Kconfig  |  14 +
>  drivers/media/cec/i2c/Makefile |   5 +
>  drivers/media/cec/i2c/ch7322.c | 503 +++++++++++++++++++++++++++++++++
>  6 files changed, 525 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/media/cec/i2c/Kconfig
>  create mode 100644 drivers/media/cec/i2c/Makefile
>  create mode 100644 drivers/media/cec/i2c/ch7322.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c1c17ca17830..e2341eaaaf5e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4107,6 +4107,7 @@ L:	linux-media@xxxxxxxxxxxxxxx
>  S:	Maintained
>  T:	git git://linuxtv.org/media_tree.git
>  F:	Documentation/devicetree/bindings/media/i2c/chontel,ch7322.yaml
> +F:	drivers/media/cec/i2c/ch7322.c
>  
>  CIRRUS LOGIC AUDIO CODEC DRIVERS
>  M:	James Schulman <james.schulman@xxxxxxxxxx>
> diff --git a/drivers/media/cec/Kconfig b/drivers/media/cec/Kconfig
> index 7e830444bdbb..9ba3a00dce31 100644
> --- a/drivers/media/cec/Kconfig
> +++ b/drivers/media/cec/Kconfig
> @@ -33,6 +33,7 @@ menuconfig MEDIA_CEC_SUPPORT
>  	  adapter that supports HDMI CEC.
>  
>  if MEDIA_CEC_SUPPORT
> +source "drivers/media/cec/i2c/Kconfig"
>  source "drivers/media/cec/platform/Kconfig"
>  source "drivers/media/cec/usb/Kconfig"
>  endif
> diff --git a/drivers/media/cec/Makefile b/drivers/media/cec/Makefile
> index 74e80e1b3571..23539339bc81 100644
> --- a/drivers/media/cec/Makefile
> +++ b/drivers/media/cec/Makefile
> @@ -1,2 +1,2 @@
>  # SPDX-License-Identifier: GPL-2.0
> -obj-y += core/ platform/ usb/
> +obj-y += core/ i2c/ platform/ usb/
> diff --git a/drivers/media/cec/i2c/Kconfig b/drivers/media/cec/i2c/Kconfig
> new file mode 100644
> index 000000000000..e445ca2110b3
> --- /dev/null
> +++ b/drivers/media/cec/i2c/Kconfig
> @@ -0,0 +1,14 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# I2C drivers
> +
> +config CEC_CH7322
> +	tristate "Chrontel CH7322 CEC controller"
> +	select I2C
> +	select REGMAP_I2C
> +	select CEC_CORE
> +	help
> +	  This is a driver for the Chrontel CH7322 CEC controller. It uses the
> +	  generic CEC framework interface.
> +	  CEC bus is present in the HDMI connector and enables communication
> +	  between compatible devices.
> diff --git a/drivers/media/cec/i2c/Makefile b/drivers/media/cec/i2c/Makefile
> new file mode 100644
> index 000000000000..d7496dfd0fa4
> --- /dev/null
> +++ b/drivers/media/cec/i2c/Makefile
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for the CEC I2C device drivers.
> +#
> +obj-$(CONFIG_CEC_CH7322) += ch7322.o
> diff --git a/drivers/media/cec/i2c/ch7322.c b/drivers/media/cec/i2c/ch7322.c
> new file mode 100644
> index 000000000000..4e6976a51774
> --- /dev/null
> +++ b/drivers/media/cec/i2c/ch7322.c
> @@ -0,0 +1,503 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for the Chrontel CH7322 CEC Controller
> + *
> + * Copyright 2020 Google LLC.
> + */
> +
> +/*
> + * Notes
> + *
> + * - This device powers on in Auto Mode which has limited functionality. This
> + *   driver disables Auto Mode when it attaches.
> + *
> + */
> +
> +#include <linux/cec.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/regmap.h>
> +#include <media/cec.h>
> +
> +#define CH7322_WRITE		0x00
> +#define CH7322_WRITE_MSENT		0x80
> +#define CH7322_WRITE_BOK		0x40
> +#define CH7322_WRITE_NMASK		0x0f
> +
> +/* Write buffer is 0x01-0x10 */
> +#define CH7322_WRBUF		0x01
> +#define CH7322_WRBUF_LEN	0x10
> +
> +#define CH7322_READ		0x40
> +#define CH7322_READ_NRDT		0x80
> +#define CH7322_READ_MSENT		0x20
> +#define CH7322_READ_NMASK		0x0f
> +
> +/* Read buffer is 0x41-0x50 */
> +#define CH7322_RDBUF		0x41
> +#define CH7322_RDBUF_LEN	0x10
> +
> +#define CH7322_MODE		0x11
> +#define CH7322_MODE_AUTO		0x78
> +#define CH7322_MODE_SW			0xb5
> +
> +#define CH7322_RESET		0x12
> +#define CH7322_RESET_RST		0x00
> +
> +#define CH7322_POWER		0x13
> +#define CH7322_POWER_FPD		0x04
> +
> +#define CH7322_CFG0		0x17
> +#define CH7322_CFG0_EOBEN		0x40
> +#define CH7322_CFG0_PEOB		0x20
> +#define CH7322_CFG0_CLRSPP		0x10
> +#define CH7322_CFG0_FLOW		0x08
> +
> +#define CH7322_CFG1		0x1a
> +#define CH7322_CFG1_STDBYO		0x04
> +#define CH7322_CFG1_HPBP		0x02
> +#define CH7322_CFG1_PIO			0x01
> +
> +#define CH7322_INTCTL		0x1b
> +#define CH7322_INTCTL_INTPB		0x80
> +#define CH7322_INTCTL_STDBY		0x40
> +#define CH7322_INTCTL_HPDFALL		0x20
> +#define CH7322_INTCTL_HPDRISE		0x10
> +#define CH7322_INTCTL_RXMSG		0x08
> +#define CH7322_INTCTL_TXMSG		0x04
> +#define CH7322_INTCTL_NEWPHA		0x02
> +#define CH7322_INTCTL_ERROR		0x01
> +
> +#define CH7322_DVCLKFNH	0x1d
> +#define CH7322_DVCLKFNL	0x1e
> +
> +#define CH7322_CTL		0x31
> +#define CH7322_CTL_FSTDBY		0x80
> +#define CH7322_CTL_PLSEN		0x40
> +#define CH7322_CTL_PLSPB		0x20
> +#define CH7322_CTL_SPADL		0x10
> +#define CH7322_CTL_HINIT		0x08
> +#define CH7322_CTL_WPHYA		0x04
> +#define CH7322_CTL_H1T			0x02
> +#define CH7322_CTL_S1T			0x01
> +
> +#define CH7322_PAWH		0x32
> +#define CH7322_PAWL		0x33
> +
> +#define CH7322_ADDLW		0x34
> +#define CH7322_ADDLW_MASK	0xf0
> +
> +#define CH7322_ADDLR		0x3d
> +#define CH7322_ADDLR_HPD		0x80
> +#define CH7322_ADDLR_MASK		0x0f
> +
> +#define CH7322_INTDATA		0x3e
> +#define CH7322_INTDATA_MODE		0x80
> +#define CH7322_INTDATA_STDBY		0x40
> +#define CH7322_INTDATA_HPDFALL		0x20
> +#define CH7322_INTDATA_HPDRISE		0x10
> +#define CH7322_INTDATA_RXMSG		0x08
> +#define CH7322_INTDATA_TXMSG		0x04
> +#define CH7322_INTDATA_NEWPHA		0x02
> +#define CH7322_INTDATA_ERROR		0x01
> +
> +#define CH7322_EVENT		0x3F
> +#define CH7322_EVENT_TXERR		0x80
> +#define CH7322_EVENT_HRST		0x40
> +#define CH7322_EVENT_HFST		0x20
> +#define CH7322_EVENT_PHACHG		0x10
> +#define CH7322_EVENT_ACTST		0x08
> +#define CH7322_EVENT_PHARDY		0x04
> +#define CH7322_EVENT_BSOK		0x02
> +#define CH7322_EVENT_ERRADCF		0x01
> +
> +#define CH7322_DID		0x51
> +#define CH7322_DID_CH7322		0x5b
> +#define CH7322_DID_CH7323		0x5f
> +
> +#define CH7322_REVISIONID	0x52
> +
> +#define CH7322_PARH		0x53
> +#define CH7322_PARL		0x54
> +
> +#define CH7322_IOCFG2		0x75
> +#define CH7322_IOCFG_CIO		0x80
> +#define CH7322_IOCFG_IOCFGMASK		0x78
> +#define CH7322_IOCFG_AUDIO		0x04
> +#define CH7322_IOCFG_SPAMST		0x02
> +#define CH7322_IOCFG_SPAMSP		0x01
> +
> +#define CH7322_CTL3		0x7b
> +#define CH7322_CTL3_SWENA		0x80
> +#define CH7322_CTL3_FC_INIT		0x40
> +#define CH7322_CTL3_SML_FL		0x20
> +#define CH7322_CTL3_SM_RDST		0x10
> +#define CH7322_CTL3_SPP_CIAH		0x08
> +#define CH7322_CTL3_SPP_CIAL		0x04
> +#define CH7322_CTL3_SPP_ACTH		0x02
> +#define CH7322_CTL3_SPP_ACTL		0x01
> +
> +/* BOK status means NACK */
> +#define CH7322_TX_FLAG_NACK	BIT(0)
> +/* Device will retry automatically */
> +#define CH7322_TX_FLAG_RETRY	BIT(1)
> +
> +struct ch7322 {
> +	struct i2c_client *i2c;
> +	struct regmap *regmap;
> +	struct cec_adapter *cec;
> +	struct mutex mutex;	/* device access mutex */
> +	u8 tx_flags;
> +};
> +
> +static const struct regmap_config ch7322_regmap = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 0x7f,
> +	.disable_locking = true,
> +
> +};
> +
> +static int ch7322_send_message(struct ch7322 *ch7322, const struct cec_msg *msg)
> +{
> +	unsigned int val;
> +	unsigned int len = msg->len;
> +	int ret;
> +	int i;
> +
> +	WARN_ON(!mutex_is_locked(&ch7322->mutex));
> +
> +	if (len > CH7322_WRBUF_LEN || len < 1)
> +		return -EINVAL;
> +
> +	ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* Buffer not ready */
> +	if (!(val & CH7322_WRITE_MSENT))
> +		return -EBUSY;
> +
> +	if (cec_msg_opcode(msg) == -1 &&
> +	    cec_msg_initiator(msg) == cec_msg_destination(msg)) {
> +		ch7322->tx_flags = CH7322_TX_FLAG_NACK | CH7322_TX_FLAG_RETRY;
> +	} else if (cec_msg_is_broadcast(msg)) {
> +		ch7322->tx_flags = CH7322_TX_FLAG_NACK;
> +	} else {
> +		ch7322->tx_flags = CH7322_TX_FLAG_RETRY;
> +	}
> +
> +	ret = regmap_write(ch7322->regmap, CH7322_WRITE, len - 1);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < len; i++) {
> +		ret = regmap_write(ch7322->regmap,
> +				   CH7322_WRBUF + i, msg->msg[i]);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ch7322_receive_message(struct ch7322 *ch7322, struct cec_msg *msg)
> +{
> +	unsigned int val;
> +	int ret = 0;
> +	int i;
> +
> +	WARN_ON(!mutex_is_locked(&ch7322->mutex));
> +
> +	ret = regmap_read(ch7322->regmap, CH7322_READ, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* Message not ready */
> +	if (!(val & CH7322_READ_NRDT))
> +		return -EIO;
> +
> +	msg->len = (val & CH7322_READ_NMASK) + 1;
> +
> +	/* Read entire RDBUF to clear state */
> +	for (i = 0; i < CH7322_RDBUF_LEN; i++) {
> +		ret = regmap_read(ch7322->regmap, CH7322_RDBUF + i, &val);
> +		if (ret)
> +			return ret;
> +		msg->msg[i] = (u8)val;
> +	}
> +
> +	return 0;
> +}
> +
> +static void ch7322_tx_done(struct ch7322 *ch7322)
> +{
> +	int ret;
> +	unsigned int val;
> +	u8 status, flags;
> +
> +	mutex_lock(&ch7322->mutex);
> +	ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
> +	flags = ch7322->tx_flags;
> +	mutex_unlock(&ch7322->mutex);
> +
> +	/*
> +	 * The device returns a one-bit OK status which usually means ACK but
> +	 * actually means NACK when sending a logical address query or a
> +	 * broadcast.
> +	 */
> +	if (ret)
> +		status = CEC_TX_STATUS_ERROR;
> +	else if ((val & CH7322_WRITE_BOK) && (flags & CH7322_TX_FLAG_NACK))
> +		status = CEC_TX_STATUS_NACK;
> +	else if (val & CH7322_WRITE_BOK)
> +		status = CEC_TX_STATUS_OK;
> +	else if (flags & CH7322_TX_FLAG_NACK)
> +		status = CEC_TX_STATUS_OK;
> +	else
> +		status = CEC_TX_STATUS_NACK;
> +
> +	if (status == CEC_TX_STATUS_NACK && (flags & CH7322_TX_FLAG_RETRY))
> +		status |= CEC_TX_STATUS_MAX_RETRIES;
> +
> +	cec_transmit_attempt_done(ch7322->cec, status);
> +}
> +
> +static void ch7322_rx_done(struct ch7322 *ch7322)
> +{
> +	struct cec_msg msg;
> +	int ret;
> +
> +	mutex_lock(&ch7322->mutex);
> +	ret = ch7322_receive_message(ch7322, &msg);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	if (ret)
> +		dev_err(&ch7322->i2c->dev, "cec receive error: %d\n", ret);
> +	else
> +		cec_received_msg(ch7322->cec, &msg);
> +}
> +
> +/*
> + * This device can either monitor the DDC lines to obtain the physical address
> + * or it can allow the host to program it. This driver lets the device obtain
> + * it.
> + */
> +static void ch7322_phys_addr(struct ch7322 *ch7322)
> +{
> +	unsigned int pah, pal;
> +	int ret = 0;
> +
> +	mutex_lock(&ch7322->mutex);
> +	ret |= regmap_read(ch7322->regmap, CH7322_PARH, &pah);
> +	ret |= regmap_read(ch7322->regmap, CH7322_PARL, &pal);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	if (ret)
> +		dev_err(&ch7322->i2c->dev, "phys addr error\n");
> +	else
> +		cec_s_phys_addr(ch7322->cec, pal | (pah << 8), false);
> +}
> +
> +static void ch7322_handle_events(struct ch7322 *ch7322)
> +{
> +	unsigned int data = 0;
> +
> +	mutex_lock(&ch7322->mutex);
> +	regmap_read(ch7322->regmap, CH7322_INTDATA, &data);
> +	regmap_write(ch7322->regmap, CH7322_INTDATA, data);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	if (data & CH7322_INTDATA_HPDFALL)
> +		cec_phys_addr_invalidate(ch7322->cec);
> +
> +	if (data & CH7322_INTDATA_TXMSG)
> +		ch7322_tx_done(ch7322);
> +
> +	if (data & CH7322_INTDATA_RXMSG)
> +		ch7322_rx_done(ch7322);
> +
> +	if (data & CH7322_INTDATA_NEWPHA)
> +		ch7322_phys_addr(ch7322);
> +
> +	if (data & CH7322_INTDATA_ERROR)
> +		dev_dbg(&ch7322->i2c->dev, "unknown error\n");
> +}
> +
> +static irqreturn_t ch7322_irq(int irq, void *dev)
> +{
> +	struct ch7322 *ch7322 = dev;
> +
> +	ch7322_handle_events(ch7322);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/* This device is always enabled */
> +static int ch7322_cec_adap_enable(struct cec_adapter *adap, bool enable)
> +{
> +	return 0;
> +}
> +
> +static int ch7322_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
> +{
> +	struct ch7322 *ch7322 = cec_get_drvdata(adap);
> +	int ret;
> +
> +	mutex_lock(&ch7322->mutex);
> +	ret = regmap_update_bits(ch7322->regmap, CH7322_ADDLW,
> +				 CH7322_ADDLW_MASK, log_addr << 4);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	return ret;
> +}
> +
> +static int ch7322_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
> +				    u32 signal_free_time, struct cec_msg *msg)
> +{
> +	struct ch7322 *ch7322 = cec_get_drvdata(adap);
> +	int ret;
> +
> +	mutex_lock(&ch7322->mutex);
> +	ret = ch7322_send_message(ch7322, msg);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	return ret;
> +}
> +
> +static const struct cec_adap_ops ch7322_cec_adap_ops = {
> +	.adap_enable = ch7322_cec_adap_enable,
> +	.adap_log_addr = ch7322_cec_adap_log_addr,
> +	.adap_transmit = ch7322_cec_adap_transmit,
> +};
> +
> +static int ch7322_probe(struct i2c_client *client)
> +{
> +	struct ch7322 *ch7322;
> +	int ret;
> +	unsigned int val;
> +
> +	ch7322 = devm_kzalloc(&client->dev, sizeof(*ch7322), GFP_KERNEL);
> +	if (!ch7322)
> +		return -ENOMEM;
> +
> +	ch7322->regmap = devm_regmap_init_i2c(client, &ch7322_regmap);
> +	if (IS_ERR(ch7322->regmap))
> +		return PTR_ERR(ch7322->regmap);
> +
> +	ret = regmap_read(ch7322->regmap, CH7322_DID, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val != CH7322_DID_CH7322)
> +		return -ENOTSUPP;
> +
> +	mutex_init(&ch7322->mutex);
> +	ch7322->i2c = client;
> +	ch7322->tx_flags = 0;
> +
> +	i2c_set_clientdata(client, ch7322);
> +
> +	/* Disable auto mode */
> +	ret = regmap_write(ch7322->regmap, CH7322_MODE, CH7322_MODE_SW);
> +	if (ret)
> +		goto err_mutex;
> +
> +	/* Enable logical address register */
> +	ret = regmap_update_bits(ch7322->regmap, CH7322_CTL,
> +				 CH7322_CTL_SPADL, CH7322_CTL_SPADL);
> +	if (ret)
> +		goto err_mutex;
> +
> +	ch7322->cec = cec_allocate_adapter(&ch7322_cec_adap_ops, ch7322,
> +					   dev_name(&client->dev),
> +					   CEC_CAP_DEFAULTS, 1);
> +
> +	if (IS_ERR(ch7322->cec)) {
> +		ret = PTR_ERR(ch7322->cec);
> +		goto err_mutex;
> +	}
> +
> +	ret = cec_register_adapter(ch7322->cec, &client->dev);
> +	if (ret) {
> +		cec_delete_adapter(ch7322->cec);
> +		goto err_mutex;
> +	}
> +
> +	/* Configure and mask interrupt */
> +	ret = regmap_write(ch7322->regmap, CH7322_CFG1, 0);
> +	if (ret)
> +		goto err_cec;
> +
> +	ret = regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
> +	if (ret)
> +		goto err_cec;
> +
> +	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> +					ch7322_irq,
> +					IRQF_ONESHOT | IRQF_TRIGGER_RISING,
> +					client->name, ch7322);
> +	if (ret)
> +		goto err_cec;
> +
> +	ch7322_handle_events(ch7322);
> +
> +	/* Unmask interrupt */
> +	mutex_lock(&ch7322->mutex);
> +	ret = regmap_write(ch7322->regmap, CH7322_INTCTL, 0xff);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	if (ret)
> +		goto err_cec;
> +
> +	dev_info(&client->dev, "device registered\n");
> +
> +	return 0;
> +
> +err_cec:
> +	cec_unregister_adapter(ch7322->cec);
> +
> +err_mutex:
> +	mutex_destroy(&ch7322->mutex);
> +	return ret;
> +}
> +
> +static int ch7322_remove(struct i2c_client *client)
> +{
> +	struct ch7322 *ch7322 = i2c_get_clientdata(client);
> +
> +	/* Mask interrupt */
> +	mutex_lock(&ch7322->mutex);
> +	regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
> +	mutex_unlock(&ch7322->mutex);
> +
> +	cec_unregister_adapter(ch7322->cec);
> +	mutex_destroy(&ch7322->mutex);
> +
> +	dev_info(&client->dev, "device unregistered\n");
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id ch7322_of_match[] = {
> +	{ .compatible = "chrontel,ch7322", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ch7322_of_match);
> +
> +static struct i2c_driver ch7322_i2c_driver = {
> +	.driver = {
> +		.name = "ch7322",
> +		.of_match_table = of_match_ptr(ch7322_of_match),
> +	},
> +	.probe_new	= ch7322_probe,
> +	.remove		= ch7322_remove,
> +};
> +
> +module_i2c_driver(ch7322_i2c_driver);
> +
> +MODULE_DESCRIPTION("Chrontel CH7322 CEC Controller Driver");
> +MODULE_AUTHOR("Jeff Chase <jnchase@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> 




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