Date:   Wed, 3 Oct 2018 11:35:32 +0200
From:   jacopo mondi <jacopo@...ndi.org>
To:     ektor5 <ek5.chimenti@...il.com>
Cc:     hverkuil@...all.nl, luca.pisani@...o.org, jose.abreu@...opsys.com,
        sean@...s.org, sakari.ailus@...ux.intel.com,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Jacob Chen <jacob-chen@...wrt.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Todor Tomov <todor.tomov@...aro.org>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org
Subject: Re: [PATCH 1/2] media: add SECO cec driver

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@...il.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@...il.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@...ts.sourceforge.net (subscribers-only)
>  S:	Maintained
>  F:	drivers/mmc/host/sdricoh_cs.c
>
> +SECO BOARDS CEC DRIVER
> +M:	Ettore Chimenti <ek5.chimenti@...il.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@...omium.org>
>  R:	Andy Lutomirski <luto@...capital.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

> +         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@...il.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)
> +{
> +	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.

(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...)

> +	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);
> +
> +	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@...il.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@...il.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
>

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