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Subject: Re: [PATCH 1/2] media: add SECO cec driver
To:     jacopo mondi <jacopo@jmondi.org>, ektor5 <ek5.chimenti@gmail.com>
Cc:     luca.pisani@udoo.org, jose.abreu@synopsys.com, sean@mess.org,
        sakari.ailus@linux.intel.com,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        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>,
        Jacob Chen <jacob-chen@iotwrt.com>,
        Jacopo Mondi <jacopo+renesas@jmondi.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Todor Tomov <todor.tomov@linaro.org>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
References: <cover.1538474121.git.ek5.chimenti@gmail.com>
 <c212cb1142a412f980176b9c86fa7f6c96092cb1.1538474121.git.ek5.chimenti@gmail.com>
 <20181003093532.GF20786@w540>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <c2bfdb30-e8ed-7a4e-422d-ca852db988e9@xs4all.nl>
Date:   Thu, 4 Oct 2018 13:52:54 +0200
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On 10/03/18 11:35, jacopo mondi wrote:
> Hi Ettore,
>     thanks for the patch.
> 
> A few comments below, please have a look...
> 
> On Tue, Oct 02, 2018 at 06:59:55PM +0200, 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             |  11 +
>>  drivers/media/platform/Makefile            |   4 +
>>  drivers/media/platform/seco-cec/Makefile   |   1 +
>>  drivers/media/platform/seco-cec/seco-cec.c | 729 +++++++++++++++++++++
>>  drivers/media/platform/seco-cec/seco-cec.h | 132 ++++
>>  6 files changed, 883 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..f477764b902a 100644
>> --- a/drivers/media/platform/Kconfig
>> +++ b/drivers/media/platform/Kconfig
>> @@ -613,6 +613,17 @@ 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
>> +       select CEC_CORE
>> +       select CEC_NOTIFIER
>> +       help
>> +         This is a driver for SECO Boards integrated CEC interface. It uses the
>> +         generic CEC framework interface.
> 
> Is it worth mentioning the software framework used for implementing the driver?
> Anyway, I see this is common to most of the CEC drivers here, so I
> guess it is fine

It's not worth mentioning :-)

Not sure how and why that phrase crept into cec driver Kconfigs.

> 
>> +         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..cc7365c787ba 100644
>> --- a/drivers/media/platform/Makefile
>> +++ b/drivers/media/platform/Makefile
>> @@ -53,6 +53,10 @@ obj-$(CONFIG_VIDEO_TEGRA_HDMI_CEC)	+= tegra-cec/
>>
>>  obj-y					+= stm32/
>>
>> +obj-$(CONFIG_VIDEO_SECO_CEC)		+= seco-cec/
>> +
>> +obj-y                                   += blackfin/
>> +
> 
> Ups! Is this a leftover from some BSP code? It breaks the build on
> media-tree master (and I guess on master too)
> 
>>  obj-y					+= davinci/
>>
>>  obj-$(CONFIG_VIDEO_SH_VOU)		+= sh_vou.o
>> diff --git a/drivers/media/platform/seco-cec/Makefile b/drivers/media/platform/seco-cec/Makefile
>> new file mode 100644
>> index 000000000000..a3f2c6bd3ac0
>> --- /dev/null
>> +++ b/drivers/media/platform/seco-cec/Makefile
>> @@ -0,0 +1 @@
>> +obj-$(CONFIG_VIDEO_SECO_CEC) += seco-cec.o
> 
> This can simply be obj-y as you parse this makefile entry
> conditionally to the presence of the CONFIG_VIDEO_SECO_CEC symbol
> 
>> 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..ba3b7c144a87
>> --- /dev/null
>> +++ b/drivers/media/platform/seco-cec/seco-cec.c
>> @@ -0,0 +1,729 @@
>> +// SPDX-License-Identifier: GPL-2.0 AND BSD-3-Clause
> 
> Just make sure the AND is what you want (I only see OR clauses in
> drivers/ code). See Documentation/process/license-rules.rst
> 
>> +/*
>> + *
> Nit: empty comment line
>> + * CEC driver for SECO X86 Boards
>> + *
>> + * Author:  Ettore Chimenti <ek5.chimenti@gmail.com>
>> + * Copyright (C) 2018, SECO Srl.
>> + * Copyright (C) 2018, Aidilab Srl.
>> + *
> Nit: empty comment line
>> + */
>> +
>> +#include <linux/interrupt.h>
>> +#include <linux/gpio.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/acpi.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/delay.h>
>> +#include <linux/pci.h>
>> +#include <linux/dmi.h>
>> +
>> +/* CEC Framework */
>> +#include <media/cec.h>
>> +
>> +#include "seco-cec.h"
> 
> I would question why a header file is needed as it is not included by
> anything else
> 
>> +
>> +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 ret, status = 0;
> 
> In the rest of the function ret is used only once, and you can use
> status in its place. Please drop one of the two.
> 
>> +
>> +	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);
>> +		pr_warn("%s: SMBTIMEOUT\n", __func__);
> 
> No pr_debug/pr_warn if possible, please.
> 
>> +	}
>> +
>> +	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);
>> +		pr_debug("%s: WRITE (0x%02x - count %05d): 0x%04x\n",
>> +			 __func__, cmd, count, data);
>> +	}
>> +
>> +	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) {
>> +		pr_debug("%s: SMBTIMEOUT_1\n", __func__);
>> +		status = -EBUSY;
>> +		goto err;
>> +	}
>> +
>> +	ret = inb(HSTS);
>> +	if (ret & BRA_HSTS_ERR_MASK) {
>> +		pr_debug("%s: HSTS(0x%02X): 0x%X\n", __func__, cmd, ret);
>> +		status = -EIO;
>> +		goto err;
>> +	}
>> +
>> +	if (operation == SMBUS_READ) {
>> +		*result = ((inb(HDAT0) & 0xff) + ((inb(HDAT1) & 0xff) << 8));
>> +		pr_debug("%s: READ (0x%02x - count %05d): 0x%04x\n",
>> +			 __func__, cmd, count, *result);
>> +	}
>> +
>> +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");
>> +
> 
> Empty line
> 
>> +	} 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);
>> +	return status;
>> +}
>> +
>> +static int secocec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
>> +{
>> +	u16 enable_val = 0;
>> +	int status;
>> +
>> +	/* 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);
>> +	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 / 2 + payload_len % 2; i++) {
>> +			/* hi byte */
>> +			val = payload_msg[(i << 1) + 1] << 8;
>> +
>> +			/* lo byte */
>> +			val |= payload_msg[(i << 1)];
>> +
>> +			status = smb_wr16(SECOCEC_WRITE_DATA_00 + i, 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);
>> +	return status;
>> +}
>> +
>> +static int secocec_tx_done(struct cec_adapter *adap, u16 status_val)
>> +{
>> +	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)
>> +{
>> +	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");
>> +		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;
>> +
>> +	dev_dbg(dev, "Incoming message (payload len %d):", val);
>> +
>> +	/* 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 if present */
>> +	if (msg.len > 0) {
> 
> Am I wrong or msg.len is at least (val + 1) and val is never negative?
> If that's true, this condition is always verified.
> 
>> +		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 / 2 + payload_len % 2; i++) {
>> +			status = smb_rd16(SECOCEC_READ_DATA_00 + i, &val);
>> +			if (status)
>> +				goto err;
>> +
>> +			/* low byte, skipping header */
>> +			payload_msg[(i << 1)] = val & 0x00ff;
>> +
>> +			/* hi byte */
>> +			payload_msg[(i << 1) + 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;
>> +
>> +	dev_dbg(dev, "Message received successfully");
>> +
>> +	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) {
>> +		dev_dbg(dev, "+++++ CEC Interrupt Caught");
> 
> Just be carefull in too much printouts while handling interrupts.
> Also, I would not insert custom printout formats (here and below in
> this functions). I would simply drop this one.
> 
>> +
>> +		/* 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 \\_\"._/");
> 
> No custom funny printouts please :)
> 
>> +
>> +		val = SECOCEC_STATUS_REG_1_CEC;
>> +	}
>> +
>> +	if (status_val & SECOCEC_STATUS_REG_1_IR) {
>> +		dev_dbg(dev, "IR RC5 Interrupt Caught");
> 
> How frequent is this one? Do you need to print it out?
> 
>> +		val |= SECOCEC_STATUS_REG_1_IR;
>> +		/* TODO IRDA RX */
>> +	}
>> +
>> +	/*  Reset status register */
>> +	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
>> +	if (status)
>> +		goto err;
>> +
>> +	dev_dbg(dev, "----- CEC Interrupt Handled");
> 
> Drop this one please
> 
>> +
>> +	return IRQ_HANDLED;
>> +
>> +err:
>> +	dev_err(dev, "IRQ: Read/Write SMBus operation failed (%d)", status);
>> +
>> +	/*  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)

If you compare this driver with cros-ec-cec.c, then you'll see that
there this function is under "#if IS_ENABLED(CONFIG_PCI) && IS_ENABLED(CONFIG_DMI)".

I think you should do the same and (just like cros-ec-cec.c) add a dummy function
in the #else part.

>> +{
>> +	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);
> 
> Nit: it's usually nice to have an empty line before return (here and in
> other places). Not mandatory though.
> 
>> +			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;
>> +	u8 cec_caps;
>> +	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;
>> +	}
>> +
>> +#ifdef CONFIG_CEC_NOTIFIER
> 
> Your Kconfig entry selects CEC_NOTIFIER.

Yes, this #ifdef line can be dropped.

> 
> (I won't comment on the cec_notifier handling part, as I don't know
> much. I just see other drivers registering and getting the notifier
> using the cec_notifier_ functions, while it seems to me you don't.
> Maybe it's fine...)

It's fine :-)

> 
>> +	ret = secocec_cec_get_notifier(&secocec->notifier);
>> +	if (ret) {
>> +		dev_err(dev, "no CEC notifier available\n");
>> +		goto err;
>> +	}
>> +#endif
>> +
>> +	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 */
>> +	cec_caps = CEC_CAP_DEFAULTS;
>> +
>> +	secocec->cec_adap = cec_allocate_adapter(&secocec_cec_adap_ops,
>> +						 secocec,
>> +						 dev_name(dev),
>> +						 cec_caps, SECOCEC_MAX_ADDRS);

You can drop cec_caps and just pass CEC_CAP_DEFAULTS directly.

>> +
>> +	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
> 
> I see CONFIG_PM_SLEEP is only selected if support for
> 'suspend'/'hibernate' is enabled. Is this what you want, or you should
> check for CONFIG_PM?
> 
>> +static int secocec_suspend(struct device *dev)
>> +{
>> +	u16 val;
>> +	int status;
>> +
>> +	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)
>> +{
>> +	u16 val;
>> +	int status;
>> +
>> +	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,
>> +};
> 
> As you can see most of my comments are nits or trivial things. I would
> wait for more feedbacks on the CEC and x86/SMbus part from others before
> sending v2 if I were you :)
> 
> Thanks
>    j
> 
> 
>> +
>> +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..cc7f0cba8e9e
>> --- /dev/null
>> +++ b/drivers/media/platform/seco-cec/seco-cec.h
>> @@ -0,0 +1,132 @@
>> +/* SPDX-License-Identifier: GPL-2.0 AND 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__ */
>> --
>> 2.18.0
>>

Regards,

	Hans