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Date:   Fri, 19 Oct 2018 15:02:07 +0200
From:   ektor5 <ek5.chimenti@gmail.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>
Cc:     luca.pisani@udoo.org, jose.abreu@synopsys.com, sean@mess.org,
        sakari.ailus@linux.intel.com, jacopo@jmondi.org,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "David S. Miller" <davem@davemloft.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Todor Tomov <todor.tomov@linaro.org>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Jacopo Mondi <jacopo+renesas@jmondi.org>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Subject: Re: [PATCH v3 1/2] media: add SECO cec driver
Message-ID: <20181019130205.lqb3sopqqangefr4@Ettosoft-T55>
References: <cover.1539807092.git.ek5.chimenti@gmail.com>
 <3682be6c6cf7263f165080b9a1123017a23489a0.1539807092.git.ek5.chimenti@gmail.com>
 <d874bf66-e4ad-0c98-711d-3c79d0342a67@xs4all.nl>
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Hi Hans,

On Thu, Oct 18, 2018 at 09:14:55AM +0200, Hans Verkuil wrote:
> Hi Ettore,
> 
> Just a few small things and it is ready to go:
> 
> On 10/17/2018 11:31 PM, ektor5 wrote:
> > From: Ettore Chimenti <ek5.chimenti@gmail.com>
> > 
> > This patch adds support to the CEC device implemented with a STM32
> > microcontroller in X86 SECO Boards, including UDOO X86.
> > 
> > The communication is achieved via Braswell integrated SMBus
> > (i2c-i801). The driver use direct access to the PCI addresses, due to
> > the limitations of the specific driver in presence of ACPI calls.
> > 
> > The basic functionalities are tested with success with cec-ctl and
> > cec-compliance.
> > 
> > Inspired by cros-ec-cec implementation, attaches to i915 driver
> > cec-notifier.
> > 
> > Signed-off-by: Ettore Chimenti <ek5.chimenti@gmail.com>
> > ---
> >  MAINTAINERS                                |   6 +
> >  drivers/media/platform/Kconfig             |  12 +
> >  drivers/media/platform/Makefile            |   2 +
> >  drivers/media/platform/seco-cec/Makefile   |   1 +
> >  drivers/media/platform/seco-cec/seco-cec.c | 699 +++++++++++++++++++++
> >  drivers/media/platform/seco-cec/seco-cec.h | 130 ++++
> >  6 files changed, 850 insertions(+)
> >  create mode 100644 drivers/media/platform/seco-cec/Makefile
> >  create mode 100644 drivers/media/platform/seco-cec/seco-cec.c
> >  create mode 100644 drivers/media/platform/seco-cec/seco-cec.h
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 4ece30f15777..1062912a5ff4 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12972,6 +12972,12 @@ L:	sdricohcs-devel@lists.sourceforge.net (subscribers-only)
> >  S:	Maintained
> >  F:	drivers/mmc/host/sdricoh_cs.c
> >  
> > +SECO BOARDS CEC DRIVER
> > +M:	Ettore Chimenti <ek5.chimenti@gmail.com>
> > +S:	Maintained
> > +F:	drivers/media/platform/seco-cec/seco-cec.c
> > +F:	drivers/media/platform/seco-cec/seco-cec.h
> > +
> >  SECURE COMPUTING
> >  M:	Kees Cook <keescook@chromium.org>
> >  R:	Andy Lutomirski <luto@amacapital.net>
> > diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> > index 94c1fe0e9787..51cd1fd005e3 100644
> > --- a/drivers/media/platform/Kconfig
> > +++ b/drivers/media/platform/Kconfig
> > @@ -613,6 +613,18 @@ config VIDEO_TEGRA_HDMI_CEC
> >  	 The CEC bus is present in the HDMI connector and enables communication
> >  	 between compatible devices.
> >  
> > +config VIDEO_SECO_CEC
> > +	tristate "SECO Boards HDMI CEC driver"
> > +	depends on (X86 || IA64) || COMPILE_TEST
> > +	depends on PCI && DMI
> > +	select CEC_CORE
> > +	select CEC_NOTIFIER
> > +	help
> > +	  This is a driver for SECO Boards integrated CEC interface.
> > +	  Selecting it will enable support for this device.
> > +	  CEC bus is present in the HDMI connector and enables communication
> > +	  between compatible devices.
> > +
> >  endif #CEC_PLATFORM_DRIVERS
> >  
> >  menuconfig SDR_PLATFORM_DRIVERS
> > diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> > index 41322ab65802..5d2b06c4c68a 100644
> > --- a/drivers/media/platform/Makefile
> > +++ b/drivers/media/platform/Makefile
> > @@ -53,6 +53,8 @@ obj-$(CONFIG_VIDEO_TEGRA_HDMI_CEC)	+= tegra-cec/
> >  
> >  obj-y					+= stm32/
> >  
> > +obj-$(CONFIG_VIDEO_SECO_CEC)		+= seco-cec/
> > +
> >  obj-y					+= davinci/
> >  
> >  obj-$(CONFIG_VIDEO_SH_VOU)		+= sh_vou.o
> > diff --git a/drivers/media/platform/seco-cec/Makefile b/drivers/media/platform/seco-cec/Makefile
> > new file mode 100644
> > index 000000000000..09900b087d02
> > --- /dev/null
> > +++ b/drivers/media/platform/seco-cec/Makefile
> > @@ -0,0 +1 @@
> > +obj-y += seco-cec.o
> > diff --git a/drivers/media/platform/seco-cec/seco-cec.c b/drivers/media/platform/seco-cec/seco-cec.c
> > new file mode 100644
> > index 000000000000..9ac9a1f36bc0
> > --- /dev/null
> > +++ b/drivers/media/platform/seco-cec/seco-cec.c
> > @@ -0,0 +1,699 @@
> > +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
> > +/*
> > + * CEC driver for SECO X86 Boards
> > + *
> > + * Author:  Ettore Chimenti <ek5.chimenti@gmail.com>
> > + * Copyright (C) 2018, SECO Srl.
> > + * Copyright (C) 2018, Aidilab Srl.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/delay.h>
> > +#include <linux/dmi.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/gpio.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/pci.h>
> > +#include <linux/platform_device.h>
> > +
> > +/* CEC Framework */
> > +#include <media/cec.h>
> > +
> > +#include "seco-cec.h"
> > +
> > +struct secocec_data {
> > +	struct device *dev;
> > +	struct platform_device *pdev;
> > +	struct cec_adapter *cec_adap;
> > +	struct cec_notifier *notifier;
> > +	int irq;
> > +};
> > +
> > +#define smb_wr16(cmd, data) smb_word_op(CMD_WORD_DATA, SECOCEC_MICRO_ADDRESS, \
> > +					     cmd, data, SMBUS_WRITE, NULL)
> > +#define smb_rd16(cmd, res) smb_word_op(CMD_WORD_DATA, SECOCEC_MICRO_ADDRESS, \
> > +				       cmd, 0, SMBUS_READ, res)
> > +
> > +static int smb_word_op(short data_format, u16 slave_addr, u8 cmd, u16 data,
> > +		       u8 operation, u16 *result)
> > +{
> > +	unsigned int count;
> > +	short _data_format;
> > +	int status = 0;
> > +
> > +	switch (data_format) {
> > +	case CMD_BYTE_DATA:
> > +		_data_format = BRA_SMB_CMD_BYTE_DATA;
> > +		break;
> > +	case CMD_WORD_DATA:
> > +		_data_format = BRA_SMB_CMD_WORD_DATA;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	/* Active wait until ready */
> > +	for (count = 0; count <= SMBTIMEOUT; ++count) {
> > +		if (!(inb(HSTS) & BRA_INUSE_STS))
> > +			break;
> > +		udelay(SMB_POLL_UDELAY);
> > +	}
> > +
> > +	if (count > SMBTIMEOUT)
> > +		/* Reset the lock instead of failing */
> > +		outb(0xff, HSTS);
> > +
> > +	outb(0x00, HCNT);
> > +	outb((u8)(slave_addr & 0xfe) | operation, XMIT_SLVA);
> > +	outb(cmd, HCMD);
> > +	inb(HCNT);
> > +
> > +	if (operation == SMBUS_WRITE) {
> > +		outb((u8)data, HDAT0);
> > +		outb((u8)(data >> 8), HDAT1);
> > +	}
> > +
> > +	outb(BRA_START + _data_format, HCNT);
> > +
> > +	for (count = 0; count <= SMBTIMEOUT; count++) {
> > +		if (!(inb(HSTS) & BRA_HOST_BUSY))
> > +			break;
> > +		udelay(SMB_POLL_UDELAY);
> > +	}
> > +
> > +	if (count > SMBTIMEOUT) {
> > +		status = -EBUSY;
> > +		goto err;
> > +	}
> > +
> > +	if (inb(HSTS) & BRA_HSTS_ERR_MASK) {
> > +		status = -EIO;
> > +		goto err;
> > +	}
> > +
> > +	if (operation == SMBUS_READ)
> > +		*result = ((inb(HDAT0) & 0xff) + ((inb(HDAT1) & 0xff) << 8));
> > +
> > +err:
> > +	outb(0xff, HSTS);
> > +	return status;
> > +}
> > +
> > +static int secocec_adap_enable(struct cec_adapter *adap, bool enable)
> > +{
> > +	struct secocec_data *cec = cec_get_drvdata(adap);
> > +	struct device *dev = cec->dev;
> > +	u16 val = 0;
> > +	int status;
> > +
> > +	if (enable) {
> > +		/* Clear the status register */
> > +		status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
> > +		if (status)
> > +			goto err;
> > +
> > +		status = smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +		if (status)
> > +			goto err;
> > +
> > +		/* Enable the interrupts */
> > +		status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
> > +		if (status)
> > +			goto err;
> > +
> > +		status = smb_wr16(SECOCEC_ENABLE_REG_1,
> > +				  val | SECOCEC_ENABLE_REG_1_CEC);
> > +		if (status)
> > +			goto err;
> > +
> > +		dev_dbg(dev, "Device enabled");
> > +	} else {
> > +		/* Clear the status register */
> > +		status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
> > +		if (status)
> > +			goto err;
> > +
> > +		status = smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +		if (status)
> > +			goto err;
> > +
> > +		/* Disable the interrupts */
> > +		status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
> > +		if (status)
> > +			goto err;
> > +
> > +		status = smb_wr16(SECOCEC_ENABLE_REG_1, val &
> > +				  ~SECOCEC_ENABLE_REG_1_CEC &
> > +				  ~SECOCEC_ENABLE_REG_1_IR);
> > +		if (status)
> > +			goto err;
> > +
> > +		dev_dbg(dev, "Device disabled");
> > +	}
> > +
> > +	return 0;
> > +err:
> > +	dev_err(dev, "Adapter setup failed (%d)", status);
> 
> Drop the dev_dbg/dev_err lines: the cec module has enough debugging
> already.
> 
> > +	return status;
> 
> This should be:
> 
> 	return enable ? status : 0;
> 
> Disabling shouldn't return an error, it would result in a WARN from
> the cec framework.
> 
> In fact, I would drop all the error checks in the disable path since they
> are ignored anyway.

Ah, ok. I'll remove all goto in the disable part.

> 
> > +}
> > +
> > +static int secocec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
> > +{
> > +	u16 enable_val = 0;
> > +	int status;
> 
> If logical_addr == CEC_LOG_ADDR_INVALID, then this function must not return
> an error or the CEC framework will WARN about it.
> 
> > +
> > +	/* Disable device */
> > +	status = smb_rd16(SECOCEC_ENABLE_REG_1, &enable_val);
> > +	if (status)
> > +		return status;
> > +
> > +	status = smb_wr16(SECOCEC_ENABLE_REG_1,
> > +			  enable_val & ~SECOCEC_ENABLE_REG_1_CEC);
> > +	if (status)
> > +		return status;
> > +
> > +	/* Write logical address */
> > +	status = smb_wr16(SECOCEC_DEVICE_LA, logical_addr);
> 
> So does writing CEC_LOG_ADDR_INVALID (0xff) invalidate all logical
> addresses? I see no special code for that. If that is indeed the
> case, then you should document this.

The micro can have only one LA at a time. 

In the micro datasheet there isn't any reference to an invalid addr, so
it shouldn't complain. It will just set LA = 0xf. Is this correct or it
should disable the device instead?

> 
> > +	if (status)
> > +		return status;
> > +
> > +	/* Re-enable device */
> > +	status = smb_wr16(SECOCEC_ENABLE_REG_1,
> > +			  enable_val | SECOCEC_ENABLE_REG_1_CEC);
> > +	if (status)
> > +		return status;
> > +
> > +	return 0;
> > +}
> > +
> > +static int secocec_adap_transmit(struct cec_adapter *adap, u8 attempts,
> > +				 u32 signal_free_time, struct cec_msg *msg)
> > +{
> > +	struct secocec_data *cec = cec_get_drvdata(adap);
> > +	struct device *dev = cec->dev;
> > +	u16 payload_len, payload_id_len, destination, val = 0;
> > +	u8 *payload_msg;
> > +	int status;
> > +	u8 i;
> > +
> > +	/* Device msg len already accounts for header */
> > +	payload_id_len = msg->len - 1;
> > +
> > +	/* Send data length */
> > +	status = smb_wr16(SECOCEC_WRITE_DATA_LENGTH, payload_id_len);
> > +	if (status)
> > +		goto err;
> > +
> > +	/* Send Operation ID if present */
> > +	if (payload_id_len > 0) {
> > +		status = smb_wr16(SECOCEC_WRITE_OPERATION_ID, msg->msg[1]);
> > +		if (status)
> > +			goto err;
> > +	}
> > +	/* Send data if present */
> > +	if (payload_id_len > 1) {
> > +		/* Only data; */
> > +		payload_len = msg->len - 2;
> > +		payload_msg = &msg->msg[2];
> > +
> > +		/* Copy message into registers */
> > +		for (i = 0; i < payload_len; i += 2) {
> > +			/* hi byte */
> > +			val = payload_msg[i + 1] << 8;
> > +
> > +			/* lo byte */
> > +			val |= payload_msg[i];
> > +
> > +			status = smb_wr16(SECOCEC_WRITE_DATA_00 + i / 2, val);
> > +			if (status)
> > +				goto err;
> > +		}
> > +	}
> > +	/* Send msg source/destination and fire msg */
> > +	destination = msg->msg[0];
> > +	status = smb_wr16(SECOCEC_WRITE_BYTE0, destination);
> > +	if (status)
> > +		goto err;
> > +
> > +	return 0;
> > +
> > +err:
> > +	dev_err(dev, "Transmit failed (%d)", status);
> 
> You can drop this: the cec module has already debug code for that.
> 
> > +	return status;
> > +}
> > +
> > +static int secocec_tx_done(struct cec_adapter *adap, u16 status_val)
> 
> Just return void since the return code is ignored anyway.

Ok, will drop those.

> 
> > +{
> > +	int status = 0;
> > +
> > +	if (status_val & SECOCEC_STATUS_TX_ERROR_MASK) {
> > +		if (status_val & SECOCEC_STATUS_TX_NACK_ERROR) {
> > +			cec_transmit_attempt_done(adap, CEC_TX_STATUS_NACK);
> > +			status = -EAGAIN;
> > +		} else {
> > +			cec_transmit_attempt_done(adap, CEC_TX_STATUS_ERROR);
> > +			status = -EIO;
> > +		}
> > +	} else {
> > +		cec_transmit_attempt_done(adap, CEC_TX_STATUS_OK);
> > +	}
> > +
> > +	/* Reset status reg */
> > +	status_val = SECOCEC_STATUS_TX_ERROR_MASK |
> > +		SECOCEC_STATUS_MSG_SENT_MASK |
> > +		SECOCEC_STATUS_TX_NACK_ERROR;
> > +	smb_wr16(SECOCEC_STATUS, status_val);
> > +
> > +	return status;
> > +}
> > +
> > +static int secocec_rx_done(struct cec_adapter *adap, u16 status_val)
> > +{
> 
> Ditto.
> 
> > +	struct secocec_data *cec = cec_get_drvdata(adap);
> > +	struct device *dev = cec->dev;
> > +	struct cec_msg msg = { };
> > +	bool flag_overflow = false;
> > +	u8 payload_len, i = 0;
> > +	u8 *payload_msg;
> > +	u16 val = 0;
> > +	int status;
> > +
> > +	if (status_val & SECOCEC_STATUS_RX_OVERFLOW_MASK) {
> > +		dev_warn(dev, "Received more than 16 bytes. Discarding");
> 
> Is it better to just receive the first 16 bytes?

In case of an overflow, it should discard the overflowing bytes, but I
don't have any equipment that can test this. (this device can send up to
16 bytes).

> 
> > +		flag_overflow = true;
> > +	}
> > +
> > +	if (status_val & SECOCEC_STATUS_RX_ERROR_MASK) {
> > +		dev_warn(dev, "Message received with errors. Discarding");
> > +		status = -EIO;
> > +		goto rxerr;
> > +	}
> > +
> > +	/* Read message length */
> > +	status = smb_rd16(SECOCEC_READ_DATA_LENGTH, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	/* Device msg len already accounts for the header */
> > +	msg.len = min(val + 1, CEC_MAX_MSG_SIZE);
> > +
> > +	/* Read logical address */
> > +	status = smb_rd16(SECOCEC_READ_BYTE0, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	/* device stores source LA and destination */
> > +	msg.msg[0] = val;
> > +
> > +	/* Read operation ID */
> > +	status = smb_rd16(SECOCEC_READ_OPERATION_ID, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	msg.msg[1] = val;
> > +
> > +	/* Read data if present */
> > +	if (msg.len > 1) {
> > +		payload_len = msg.len - 2;
> > +		payload_msg = &msg.msg[2];
> > +
> > +		/* device stores 2 bytes in every 16-bit val */
> > +		for (i = 0; i < payload_len; i += 2) {
> > +			status = smb_rd16(SECOCEC_READ_DATA_00 + i / 2, &val);
> > +			if (status)
> > +				goto err;
> > +
> > +			/* low byte, skipping header */
> > +			payload_msg[i] = val & 0x00ff;
> > +
> > +			/* hi byte */
> > +			payload_msg[i + 1] = (val & 0xff00) >> 8;
> > +		}
> > +	}
> > +
> > +	cec_received_msg(cec->cec_adap, &msg);
> > +
> > +	/* Reset status reg */
> > +	status_val = SECOCEC_STATUS_MSG_RECEIVED_MASK;
> > +	if (flag_overflow)
> > +		status_val |= SECOCEC_STATUS_RX_OVERFLOW_MASK;
> > +
> > +	status = smb_wr16(SECOCEC_STATUS, status_val);
> > +	if (status)
> > +		goto err;
> > +
> > +	return 0;
> > +
> > +rxerr:
> > +	/* Reset error reg */
> > +	status_val = SECOCEC_STATUS_MSG_RECEIVED_MASK |
> > +		SECOCEC_STATUS_RX_ERROR_MASK;
> > +	if (flag_overflow)
> > +		status_val |= SECOCEC_STATUS_RX_OVERFLOW_MASK;
> > +	smb_wr16(SECOCEC_STATUS, status_val);
> > +
> > +err:
> > +	dev_err(dev, "Receive message failed (%d)", status);
> > +	return status;
> > +}
> > +
> > +struct cec_adap_ops secocec_cec_adap_ops = {
> > +	/* Low-level callbacks */
> > +	.adap_enable = secocec_adap_enable,
> > +	.adap_log_addr = secocec_adap_log_addr,
> > +	.adap_transmit = secocec_adap_transmit,
> > +};
> > +
> > +static irqreturn_t secocec_irq_handler(int irq, void *priv)
> > +{
> > +	struct secocec_data *cec = priv;
> > +	struct device *dev = cec->dev;
> > +	u16 status_val, cec_val, val = 0;
> > +	int status;
> > +
> > +	/*  Read status register */
> > +	status = smb_rd16(SECOCEC_STATUS_REG_1, &status_val);
> > +	if (status)
> > +		goto err;
> > +
> > +	if (status_val & SECOCEC_STATUS_REG_1_CEC) {
> > +		/* Read CEC status register */
> > +		status = smb_rd16(SECOCEC_STATUS, &cec_val);
> > +		if (status)
> > +			goto err;
> > +
> > +		if (cec_val & SECOCEC_STATUS_MSG_RECEIVED_MASK)
> > +			secocec_rx_done(cec->cec_adap, cec_val);
> > +
> > +		if (cec_val & SECOCEC_STATUS_MSG_SENT_MASK)
> > +			secocec_tx_done(cec->cec_adap, cec_val);
> > +
> > +		if ((~cec_val & SECOCEC_STATUS_MSG_SENT_MASK) &&
> > +		    (~cec_val & SECOCEC_STATUS_MSG_RECEIVED_MASK))
> > +			dev_warn(dev,
> > +				 "Message not received or sent, but interrupt fired");
> 
> Use dev_warn_once
> 
> > +
> > +		val = SECOCEC_STATUS_REG_1_CEC;
> > +	}
> > +
> > +	if (status_val & SECOCEC_STATUS_REG_1_IR) {
> > +		dev_dbg(dev, "IR RC5 Interrupt Caught");
> > +		val |= SECOCEC_STATUS_REG_1_IR;
> > +		/* TODO IRDA RX */
> > +	}
> > +
> > +	/*  Reset status register */
> > +	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +	if (status)
> > +		goto err;
> > +
> > +	return IRQ_HANDLED;
> > +
> > +err:
> > +	dev_err(dev, "IRQ: Read/Write SMBus operation failed (%d)", status);
> 
> dev_err_once
> 
> This really shouldn't happen, but if it happens, then you don't want
> this flooding the log.

I didn't know this function, will use more often for sure.

> 
> > +
> > +	/*  Reset status register */
> > +	val = SECOCEC_STATUS_REG_1_CEC | SECOCEC_STATUS_REG_1_IR;
> > +	smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +struct cec_dmi_match {
> > +	char *sys_vendor;
> > +	char *product_name;
> > +	char *devname;
> > +	char *conn;
> > +};
> > +
> > +static const struct cec_dmi_match secocec_dmi_match_table[] = {
> > +	/* UDOO X86 */
> > +	{ "SECO", "UDOO x86", "0000:00:02.0", "Port B" },
> > +};
> > +
> > +static int secocec_cec_get_notifier(struct cec_notifier **notify)
> > +{
> > +	int i;
> > +
> > +	for (i = 0 ; i < ARRAY_SIZE(secocec_dmi_match_table) ; ++i) {
> > +		const struct cec_dmi_match *m = &secocec_dmi_match_table[i];
> > +
> > +		if (dmi_match(DMI_SYS_VENDOR, m->sys_vendor) &&
> > +		    dmi_match(DMI_PRODUCT_NAME, m->product_name)) {
> > +			struct device *d;
> > +
> > +			/* Find the device, bail out if not yet registered */
> > +			d = bus_find_device_by_name(&pci_bus_type, NULL,
> > +						    m->devname);
> > +			if (!d)
> > +				return -EPROBE_DEFER;
> > +
> > +			*notify = cec_notifier_get_conn(d, m->conn);
> > +
> > +			return 0;
> > +		}
> > +	}
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +static int secocec_acpi_probe(struct secocec_data *sdev)
> > +{
> > +	struct device *dev = sdev->dev;
> > +	struct gpio_desc *gpio;
> > +	int irq = 0;
> > +
> > +	gpio = devm_gpiod_get(dev, NULL, GPIOF_IN);
> > +	if (IS_ERR(gpio)) {
> > +		dev_err(dev, "Cannot request interrupt gpio");
> > +		return PTR_ERR(gpio);
> > +	}
> > +
> > +	irq = gpiod_to_irq(gpio);
> > +	if (irq < 0) {
> > +		dev_err(dev, "Cannot find valid irq");
> > +		return -ENODEV;
> > +	}
> > +	dev_dbg(dev, "irq-gpio is bound to IRQ %d", irq);
> > +
> > +	sdev->irq = irq;
> > +
> > +	return 0;
> > +}
> > +
> > +static int secocec_probe(struct platform_device *pdev)
> > +{
> > +	struct secocec_data *secocec;
> > +	struct device *dev = &pdev->dev;
> > +	int ret;
> > +	u16 val;
> > +
> > +	secocec = devm_kzalloc(dev, sizeof(*secocec), GFP_KERNEL);
> > +	if (!secocec)
> > +		return -ENOMEM;
> > +
> > +	dev_set_drvdata(dev, secocec);
> > +
> > +	/* Request SMBus regions */
> > +	if (!request_muxed_region(BRA_SMB_BASE_ADDR, 7, "CEC00001")) {
> > +		dev_err(dev, "Request memory region failed");
> > +		return -ENXIO;
> > +	}
> > +
> > +	secocec->pdev = pdev;
> > +	secocec->dev = dev;
> > +
> > +	if (!has_acpi_companion(dev)) {
> > +		dev_dbg(dev, "Cannot find any ACPI companion");
> > +		ret = -ENODEV;
> > +		goto err;
> > +	}
> > +
> > +	ret = secocec_acpi_probe(secocec);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot assign gpio to IRQ");
> > +		ret = -ENODEV;
> > +		goto err;
> > +	}
> > +
> > +	dev_dbg(dev, "IRQ detected at %d", secocec->irq);
> > +
> > +	/* Firmware version check */
> > +	ret = smb_rd16(SECOCEC_VERSION, &val);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot check fw version");
> > +		goto err;
> > +	}
> > +	if (val < SECOCEC_LATEST_FW) {
> > +		dev_err(dev, "CEC Firmware not supported (v.%04x). Use ver > v.%04x",
> > +			val, SECOCEC_LATEST_FW);
> > +		ret = -EINVAL;
> > +		goto err;
> > +	}
> > +
> > +	ret = secocec_cec_get_notifier(&secocec->notifier);
> > +	if (ret) {
> > +		dev_err(dev, "no CEC notifier available\n");
> > +		goto err;
> > +	}
> > +
> > +	ret = devm_request_threaded_irq(dev,
> > +					secocec->irq,
> > +					NULL,
> > +					secocec_irq_handler,
> > +					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
> > +					dev_name(&pdev->dev), secocec);
> > +
> > +	if (ret) {
> > +		dev_err(dev, "Cannot request IRQ %d", secocec->irq);
> > +		ret = -EIO;
> > +		goto err;
> > +	}
> > +
> > +	/* Allocate CEC adapter */
> > +	secocec->cec_adap = cec_allocate_adapter(&secocec_cec_adap_ops,
> > +						 secocec,
> > +						 dev_name(dev),
> > +						 CEC_CAP_DEFAULTS,
> > +						 SECOCEC_MAX_ADDRS);
> > +
> > +	if (IS_ERR(secocec->cec_adap)) {
> > +		ret = PTR_ERR(secocec->cec_adap);
> > +		goto err;
> > +	}
> > +
> > +	ret = cec_register_adapter(secocec->cec_adap, dev);
> > +	if (ret)
> > +		goto err_delete_adapter;
> > +
> > +	if (secocec->notifier)
> > +		cec_register_cec_notifier(secocec->cec_adap, secocec->notifier);
> > +
> > +	platform_set_drvdata(pdev, secocec);
> > +
> > +	dev_dbg(dev, "Device registered");
> > +
> > +	return ret;
> > +
> > +err_delete_adapter:
> > +	cec_delete_adapter(secocec->cec_adap);
> > +err:
> > +	dev_err(dev, "%s device probe failed\n", dev_name(dev));
> > +
> > +	return ret;
> > +}
> > +
> > +static int secocec_remove(struct platform_device *pdev)
> > +{
> > +	struct secocec_data *secocec = platform_get_drvdata(pdev);
> > +
> > +	cec_unregister_adapter(secocec->cec_adap);
> > +
> > +	if (secocec->notifier)
> > +		cec_notifier_put(secocec->notifier);
> > +
> > +	release_region(BRA_SMB_BASE_ADDR, 7);
> > +
> > +	dev_dbg(&pdev->dev, "CEC device removed");
> > +
> > +	return 0;
> > +}
> > +
> > +#ifdef CONFIG_PM_SLEEP
> > +static int secocec_suspend(struct device *dev)
> > +{
> > +	int status;
> > +	u16 val;
> > +
> > +	dev_dbg(dev, "Device going to suspend, disabling");
> > +
> > +	/* Clear the status register */
> > +	status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +	if (status)
> > +		goto err;
> > +
> > +	/* Disable the interrupts */
> > +	status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	status = smb_wr16(SECOCEC_ENABLE_REG_1, val &
> > +			  ~SECOCEC_ENABLE_REG_1_CEC & ~SECOCEC_ENABLE_REG_1_IR);
> > +	if (status)
> > +		goto err;
> > +
> > +	return 0;
> > +
> > +err:
> > +	dev_err(dev, "Suspend failed (err: %d)", status);
> > +	return status;
> > +}
> > +
> > +static int secocec_resume(struct device *dev)
> > +{
> > +	int status;
> > +	u16 val;
> > +
> > +	dev_dbg(dev, "Resuming device from suspend");
> > +
> > +	/* Clear the status register */
> > +	status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
> > +	if (status)
> > +		goto err;
> > +
> > +	/* Enable the interrupts */
> > +	status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
> > +	if (status)
> > +		goto err;
> > +
> > +	status = smb_wr16(SECOCEC_ENABLE_REG_1, val | SECOCEC_ENABLE_REG_1_CEC);
> > +	if (status)
> > +		goto err;
> > +
> > +	dev_dbg(dev, "Device resumed from suspend");
> > +
> > +	return 0;
> > +
> > +err:
> > +	dev_err(dev, "Resume failed (err: %d)", status);
> > +	return status;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(secocec_pm_ops, secocec_suspend, secocec_resume);
> > +#define SECOCEC_PM_OPS (&secocec_pm_ops)
> > +#else
> > +#define SECOCEC_PM_OPS NULL
> > +#endif
> > +
> > +#ifdef CONFIG_ACPI
> > +static const struct acpi_device_id secocec_acpi_match[] = {
> > +	{"CEC00001", 0},
> > +	{},
> > +};
> > +
> > +MODULE_DEVICE_TABLE(acpi, secocec_acpi_match);
> > +#endif
> > +
> > +static struct platform_driver secocec_driver = {
> > +	.driver = {
> > +		   .name = SECOCEC_DEV_NAME,
> > +		   .acpi_match_table = ACPI_PTR(secocec_acpi_match),
> > +		   .pm = SECOCEC_PM_OPS,
> > +	},
> > +	.probe = secocec_probe,
> > +	.remove = secocec_remove,
> > +};
> > +
> > +module_platform_driver(secocec_driver);
> > +
> > +MODULE_DESCRIPTION("SECO CEC X86 Driver");
> > +MODULE_AUTHOR("Ettore Chimenti <ek5.chimenti@gmail.com>");
> > +MODULE_LICENSE("Dual BSD/GPL");
> > diff --git a/drivers/media/platform/seco-cec/seco-cec.h b/drivers/media/platform/seco-cec/seco-cec.h
> > new file mode 100644
> > index 000000000000..93020900935e
> > --- /dev/null
> > +++ b/drivers/media/platform/seco-cec/seco-cec.h
> > @@ -0,0 +1,130 @@
> > +/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
> > +/*
> > + * SECO X86 Boards CEC register defines
> > + *
> > + * Author:  Ettore Chimenti <ek5.chimenti@gmail.com>
> > + * Copyright (C) 2018, SECO Srl.
> > + * Copyright (C) 2018, Aidilab Srl.
> > + */
> > +
> > +#ifndef __SECO_CEC_H__
> > +#define __SECO_CEC_H__
> > +
> > +#define SECOCEC_MAX_ADDRS		1
> > +#define SECOCEC_DEV_NAME		"secocec"
> > +#define SECOCEC_LATEST_FW		0x0f0b
> > +
> > +#define SMBTIMEOUT			0xffff
> > +#define SMB_POLL_UDELAY			10
> > +
> > +#define SMBUS_WRITE			0
> > +#define SMBUS_READ			1
> > +
> > +#define CMD_BYTE_DATA			0
> > +#define CMD_WORD_DATA			1
> > +
> > +/*
> > + * SMBus definitons for Braswell
> > + */
> > +
> > +#define BRA_DONE_STATUS			BIT(7)
> > +#define BRA_INUSE_STS			BIT(6)
> > +#define BRA_FAILED_OP			BIT(4)
> > +#define BRA_BUS_ERR			BIT(3)
> > +#define BRA_DEV_ERR			BIT(2)
> > +#define BRA_INTR			BIT(1)
> > +#define BRA_HOST_BUSY			BIT(0)
> > +#define BRA_HSTS_ERR_MASK   (BRA_FAILED_OP | BRA_BUS_ERR | BRA_DEV_ERR)
> > +
> > +#define BRA_PEC_EN			BIT(7)
> > +#define BRA_START			BIT(6)
> > +#define BRA_LAST__BYTE			BIT(5)
> > +#define BRA_INTREN			BIT(0)
> > +#define BRA_SMB_CMD			(7 << 2)
> > +#define BRA_SMB_CMD_QUICK		(0 << 2)
> > +#define BRA_SMB_CMD_BYTE		(1 << 2)
> > +#define BRA_SMB_CMD_BYTE_DATA		(2 << 2)
> > +#define BRA_SMB_CMD_WORD_DATA		(3 << 2)
> > +#define BRA_SMB_CMD_PROCESS_CALL	(4 << 2)
> > +#define BRA_SMB_CMD_BLOCK		(5 << 2)
> > +#define BRA_SMB_CMD_I2CREAD		(6 << 2)
> > +#define BRA_SMB_CMD_BLOCK_PROCESS	(7 << 2)
> > +
> > +#define BRA_SMB_BASE_ADDR  0x2040
> > +#define HSTS               (BRA_SMB_BASE_ADDR + 0)
> > +#define HCNT               (BRA_SMB_BASE_ADDR + 2)
> > +#define HCMD               (BRA_SMB_BASE_ADDR + 3)
> > +#define XMIT_SLVA          (BRA_SMB_BASE_ADDR + 4)
> > +#define HDAT0              (BRA_SMB_BASE_ADDR + 5)
> > +#define HDAT1              (BRA_SMB_BASE_ADDR + 6)
> > +
> > +/*
> > + * Microcontroller Address
> > + */
> > +
> > +#define SECOCEC_MICRO_ADDRESS		0x40
> > +
> > +/*
> > + * STM32 SMBus Registers
> > + */
> > +
> > +#define SECOCEC_VERSION			0x00
> > +#define SECOCEC_ENABLE_REG_1		0x01
> > +#define SECOCEC_ENABLE_REG_2		0x02
> > +#define SECOCEC_STATUS_REG_1		0x03
> > +#define SECOCEC_STATUS_REG_2		0x04
> > +
> > +#define SECOCEC_STATUS			0x28
> > +#define SECOCEC_DEVICE_LA		0x29
> > +#define SECOCEC_READ_OPERATION_ID	0x2a
> > +#define SECOCEC_READ_DATA_LENGTH	0x2b
> > +#define SECOCEC_READ_DATA_00		0x2c
> > +#define SECOCEC_READ_DATA_02		0x2d
> > +#define SECOCEC_READ_DATA_04		0x2e
> > +#define SECOCEC_READ_DATA_06		0x2f
> > +#define SECOCEC_READ_DATA_08		0x30
> > +#define SECOCEC_READ_DATA_10		0x31
> > +#define SECOCEC_READ_DATA_12		0x32
> > +#define SECOCEC_READ_BYTE0		0x33
> > +#define SECOCEC_WRITE_OPERATION_ID	0x34
> > +#define SECOCEC_WRITE_DATA_LENGTH	0x35
> > +#define SECOCEC_WRITE_DATA_00		0x36
> > +#define SECOCEC_WRITE_DATA_02		0x37
> > +#define SECOCEC_WRITE_DATA_04		0x38
> > +#define SECOCEC_WRITE_DATA_06		0x39
> > +#define SECOCEC_WRITE_DATA_08		0x3a
> > +#define SECOCEC_WRITE_DATA_10		0x3b
> > +#define SECOCEC_WRITE_DATA_12		0x3c
> > +#define SECOCEC_WRITE_BYTE0		0x3d
> > +
> > +#define SECOCEC_IR_READ_DATA		0x3e
> > +
> > +/*
> > + * Enabling register
> > + */
> > +
> > +#define SECOCEC_ENABLE_REG_1_CEC		0x1000
> > +#define SECOCEC_ENABLE_REG_1_IR			0x2000
> > +#define SECOCEC_ENABLE_REG_1_IR_PASSTHROUGH	0x4000
> > +
> > +/*
> > + * Status register
> > + */
> > +
> > +#define SECOCEC_STATUS_REG_1_CEC	SECOCEC_ENABLE_REG_1_CEC
> > +#define SECOCEC_STATUS_REG_1_IR		SECOCEC_ENABLE_REG_1_IR
> > +#define SECOCEC_STATUS_REG_1_IR_PASSTHR	SECOCEC_ENABLE_REG_1_IR_PASSTHR
> > +
> > +/*
> > + * Status data
> > + */
> > +
> > +#define SECOCEC_STATUS_MSG_RECEIVED_MASK	BIT(0)
> > +#define SECOCEC_STATUS_RX_ERROR_MASK		BIT(1)
> > +#define SECOCEC_STATUS_MSG_SENT_MASK		BIT(2)
> > +#define SECOCEC_STATUS_TX_ERROR_MASK		BIT(3)
> > +
> > +#define SECOCEC_STATUS_TX_NACK_ERROR		BIT(4)
> > +#define SECOCEC_STATUS_RX_OVERFLOW_MASK		BIT(5)
> > +
> > +#endif /* __SECO_CEC_H__ */
> > 

Thanks,
	Ettore

> 
> Regards,
> 
> 	Hans