Date:   Thu, 29 Jun 2017 00:34:33 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Todor Tomov <todor.tomov@...aro.org>
Cc:     mchehab@...nel.org, hans.verkuil@...co.com, javier@....samsung.com,
        s.nawrocki@...sung.com, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v2 04/19] media: camss: Add CSIPHY files

Hi Todor,

It's been a while --- how do you do?

Thanks for the patchset!

On Mon, Jun 19, 2017 at 05:48:24PM +0300, Todor Tomov wrote:
> These files control the CSIPHY modules which are responsible for the physical
> layer of the CSI2 receivers.
> 
> Signed-off-by: Todor Tomov <todor.tomov@...aro.org>
> ---
>  drivers/media/platform/qcom/camss-8x16/csiphy.c | 686 ++++++++++++++++++++++++
>  drivers/media/platform/qcom/camss-8x16/csiphy.h |  77 +++
>  2 files changed, 763 insertions(+)
>  create mode 100644 drivers/media/platform/qcom/camss-8x16/csiphy.c
>  create mode 100644 drivers/media/platform/qcom/camss-8x16/csiphy.h
> 
> diff --git a/drivers/media/platform/qcom/camss-8x16/csiphy.c b/drivers/media/platform/qcom/camss-8x16/csiphy.c
> new file mode 100644
> index 0000000..b9d47ca
> --- /dev/null
> +++ b/drivers/media/platform/qcom/camss-8x16/csiphy.c
> @@ -0,0 +1,686 @@
> +/*
> + * csiphy.c
> + *
> + * Qualcomm MSM Camera Subsystem - CSIPHY Module
> + *
> + * Copyright (c) 2011-2015, The Linux Foundation. All rights reserved.
> + * Copyright (C) 2016 Linaro Ltd.

How about 2017?

> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <media/media-entity.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-subdev.h>
> +

...

> +/*
> + * csiphy_init_formats - Initialize formats on all pads
> + * @sd: CSIPHY V4L2 subdevice
> + * @fh: V4L2 subdev file handle
> + *
> + * Initialize all pad formats with default values.
> + *
> + * Return 0 on success or a negative error code otherwise
> + */
> +static int csiphy_init_formats(struct v4l2_subdev *sd,
> +			       struct v4l2_subdev_fh *fh)
> +{
> +	struct v4l2_subdev_format format;

You can do:

struct v4l2_subdev_format format = { 0 };

And drop the memset. Or even better, assign the fields in declaration.

> +
> +	memset(&format, 0, sizeof(format));
> +	format.pad = MSM_CSIPHY_PAD_SINK;
> +	format.which = fh ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
> +	format.format.code = MEDIA_BUS_FMT_UYVY8_2X8;
> +	format.format.width = 1920;
> +	format.format.height = 1080;
> +
> +	return csiphy_set_format(sd, fh ? fh->pad : NULL, &format);
> +}
> +
> +/*
> + * msm_csiphy_subdev_init - Initialize CSIPHY device structure and resources
> + * @csiphy: CSIPHY device
> + * @res: CSIPHY module resources table
> + * @id: CSIPHY module id
> + *
> + * Return 0 on success or a negative error code otherwise
> + */
> +int msm_csiphy_subdev_init(struct csiphy_device *csiphy,
> +			   struct resources *res, u8 id)
> +{
> +	struct device *dev = to_device_index(csiphy, id);
> +	struct platform_device *pdev = container_of(dev,
> +						struct platform_device, dev);

to_platform_device()?

> +	struct resource *r;
> +	int i;
> +	int ret;
> +
> +	csiphy->id = id;
> +	csiphy->cfg.combo_mode = 0;
> +
> +	/* Memory */
> +
> +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, res->reg[0]);
> +	csiphy->base = devm_ioremap_resource(dev, r);
> +	if (IS_ERR(csiphy->base)) {
> +		dev_err(dev, "could not map memory\n");
> +		return PTR_ERR(csiphy->base);
> +	}
> +
> +	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, res->reg[1]);
> +	csiphy->base_clk_mux = devm_ioremap_resource(dev, r);
> +	if (IS_ERR(csiphy->base_clk_mux)) {
> +		dev_err(dev, "could not map memory\n");
> +		return PTR_ERR(csiphy->base_clk_mux);
> +	}
> +
> +	/* Interrupt */
> +
> +	r = platform_get_resource_byname(pdev, IORESOURCE_IRQ,
> +					 res->interrupt[0]);
> +	if (!r) {
> +		dev_err(dev, "missing IRQ\n");
> +		return -EINVAL;
> +	}
> +
> +	csiphy->irq = r->start;
> +	snprintf(csiphy->irq_name, sizeof(csiphy->irq_name), "%s_%s%d",
> +		 dev_name(dev), MSM_CSIPHY_NAME, csiphy->id);
> +	ret = devm_request_irq(dev, csiphy->irq, csiphy_isr,
> +			       IRQF_TRIGGER_RISING, csiphy->irq_name, csiphy);
> +	if (ret < 0) {
> +		dev_err(dev, "request_irq failed\n");

Printing the error code as well might be nice for debugging if ever needed.

> +		return ret;
> +	}
> +
> +	disable_irq(csiphy->irq);
> +
> +	/* Clocks */
> +
> +	csiphy->nclocks = 0;
> +	while (res->clock[csiphy->nclocks])
> +		csiphy->nclocks++;
> +
> +	csiphy->clock = devm_kzalloc(dev, csiphy->nclocks *
> +				     sizeof(*csiphy->clock), GFP_KERNEL);
> +	if (!csiphy->clock)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < csiphy->nclocks; i++) {
> +		csiphy->clock[i] = devm_clk_get(dev, res->clock[i]);
> +		if (IS_ERR(csiphy->clock[i]))
> +			return PTR_ERR(csiphy->clock[i]);
> +
> +		if (res->clock_rate[i]) {
> +			long clk_rate = clk_round_rate(csiphy->clock[i],
> +						       res->clock_rate[i]);
> +			if (clk_rate < 0) {
> +				dev_err(to_device_index(csiphy, csiphy->id),
> +					"clk round rate failed\n");
> +				return -EINVAL;
> +			}
> +			ret = clk_set_rate(csiphy->clock[i], clk_rate);
> +			if (ret < 0) {
> +				dev_err(to_device_index(csiphy, csiphy->id),
> +					"clk set rate failed\n");
> +				return ret;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * csiphy_link_setup - Setup CSIPHY connections
> + * @entity: Pointer to media entity structure
> + * @local: Pointer to local pad
> + * @remote: Pointer to remote pad
> + * @flags: Link flags
> + *
> + * Rreturn 0 on success
> + */
> +static int csiphy_link_setup(struct media_entity *entity,
> +			     const struct media_pad *local,
> +			     const struct media_pad *remote, u32 flags)
> +{
> +	if ((local->flags & MEDIA_PAD_FL_SOURCE) &&
> +	    (flags & MEDIA_LNK_FL_ENABLED)) {
> +		struct v4l2_subdev *sd;
> +		struct csiphy_device *csiphy;
> +		struct csid_device *csid;
> +
> +		if (media_entity_remote_pad((struct media_pad *)local))

This is ugly.

What do you intend to find with media_entity_remote_pad()? The pad flags
haven't been assigned to the pad yet, so media_entity_remote_pad() could
give you something else than remote.

> +			return -EBUSY;
> +
> +		sd = container_of(entity, struct v4l2_subdev, entity);

media_entity_to_v4l2_subdev().

> +		csiphy = v4l2_get_subdevdata(sd);
> +
> +		sd = container_of(remote->entity, struct v4l2_subdev, entity);

Ditto.

> +		csid = v4l2_get_subdevdata(sd);
> +
> +		csiphy->cfg.csid_id = csid->id;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_core_ops csiphy_core_ops = {
> +	.s_power = csiphy_set_power,
> +};
> +
> +static const struct v4l2_subdev_video_ops csiphy_video_ops = {
> +	.s_stream = csiphy_set_stream,
> +};
> +
> +static const struct v4l2_subdev_pad_ops csiphy_pad_ops = {
> +	.enum_mbus_code = csiphy_enum_mbus_code,
> +	.enum_frame_size = csiphy_enum_frame_size,
> +	.get_fmt = csiphy_get_format,
> +	.set_fmt = csiphy_set_format,
> +};
> +
> +static const struct v4l2_subdev_ops csiphy_v4l2_ops = {
> +	.core = &csiphy_core_ops,
> +	.video = &csiphy_video_ops,
> +	.pad = &csiphy_pad_ops,
> +};
> +
> +static const struct v4l2_subdev_internal_ops csiphy_v4l2_internal_ops = {
> +	.open = csiphy_init_formats,
> +};
> +
> +static const struct media_entity_operations csiphy_media_ops = {
> +	.link_setup = csiphy_link_setup,
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
> +/*
> + * msm_csiphy_register_entity - Register subdev node for CSIPHY module
> + * @csiphy: CSIPHY device
> + * @v4l2_dev: V4L2 device
> + *
> + * Return 0 on success or a negative error code otherwise
> + */
> +int msm_csiphy_register_entity(struct csiphy_device *csiphy,
> +			       struct v4l2_device *v4l2_dev)
> +{
> +	struct v4l2_subdev *sd = &csiphy->subdev;
> +	struct media_pad *pads = csiphy->pads;
> +	struct device *dev = to_device_index(csiphy, csiphy->id);
> +	int ret;
> +
> +	v4l2_subdev_init(sd, &csiphy_v4l2_ops);
> +	sd->internal_ops = &csiphy_v4l2_internal_ops;
> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	snprintf(sd->name, ARRAY_SIZE(sd->name), "%s%d",
> +		 MSM_CSIPHY_NAME, csiphy->id);
> +	v4l2_set_subdevdata(sd, csiphy);
> +
> +	ret = csiphy_init_formats(sd, NULL);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to init format\n");
> +		return ret;
> +	}
> +
> +	pads[MSM_CSIPHY_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
> +	pads[MSM_CSIPHY_PAD_SRC].flags = MEDIA_PAD_FL_SOURCE;
> +
> +	sd->entity.function = MEDIA_ENT_F_IO_V4L;
> +	sd->entity.ops = &csiphy_media_ops;
> +	ret = media_entity_pads_init(&sd->entity, MSM_CSIPHY_PADS_NUM, pads);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to init media entity\n");
> +		return ret;
> +	}
> +
> +	ret = v4l2_device_register_subdev(v4l2_dev, sd);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to register subdev\n");
> +		media_entity_cleanup(&sd->entity);
> +	}
> +
> +	return ret;
> +}
> +
> +/*
> + * msm_csiphy_unregister_entity - Unregister CSIPHY module subdev node
> + * @csiphy: CSIPHY device
> + */
> +void msm_csiphy_unregister_entity(struct csiphy_device *csiphy)
> +{
> +	v4l2_device_unregister_subdev(&csiphy->subdev);
> +}
> diff --git a/drivers/media/platform/qcom/camss-8x16/csiphy.h b/drivers/media/platform/qcom/camss-8x16/csiphy.h
> new file mode 100644
> index 0000000..60330a8
> --- /dev/null
> +++ b/drivers/media/platform/qcom/camss-8x16/csiphy.h
> @@ -0,0 +1,77 @@
> +/*
> + * csiphy.h
> + *
> + * Qualcomm MSM Camera Subsystem - CSIPHY Module
> + *
> + * Copyright (c) 2011-2015, The Linux Foundation. All rights reserved.
> + * Copyright (C) 2016 Linaro Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +#ifndef QC_MSM_CAMSS_CSIPHY_H
> +#define QC_MSM_CAMSS_CSIPHY_H
> +
> +#include <linux/clk.h>
> +#include <media/media-entity.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-mediabus.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define MSM_CSIPHY_PAD_SINK 0
> +#define MSM_CSIPHY_PAD_SRC 1
> +#define MSM_CSIPHY_PADS_NUM 2
> +
> +struct csiphy_lane {
> +	u8 pos;
> +	u8 pol;
> +};
> +
> +struct csiphy_lanes_cfg {
> +	int num_data;
> +	struct csiphy_lane *data;
> +	struct csiphy_lane clk;
> +};
> +
> +struct csiphy_csi2_cfg {
> +	int settle_cnt;
> +	struct csiphy_lanes_cfg lane_cfg;
> +};
> +
> +struct csiphy_config {
> +	u8 combo_mode;
> +	u8 csid_id;
> +	struct csiphy_csi2_cfg *csi2;
> +};
> +
> +struct csiphy_device {
> +	u8 id;
> +	struct v4l2_subdev subdev;
> +	struct media_pad pads[MSM_CSIPHY_PADS_NUM];
> +	void __iomem *base;
> +	void __iomem *base_clk_mux;
> +	u32 irq;
> +	char irq_name[30];
> +	struct clk **clock;

You could add a forward declaration and avoid including the header file for
struct clk. Up to you I guess --- for a driver specific header it doesn't
really matter much.

> +	int nclocks;
> +	struct csiphy_config cfg;
> +	struct v4l2_mbus_framefmt fmt[MSM_CSIPHY_PADS_NUM];
> +};
> +
> +struct resources;
> +
> +int msm_csiphy_subdev_init(struct csiphy_device *csiphy,
> +			   struct resources *res, u8 id);
> +
> +int msm_csiphy_register_entity(struct csiphy_device *csiphy,
> +			       struct v4l2_device *v4l2_dev);
> +
> +void msm_csiphy_unregister_entity(struct csiphy_device *csiphy);
> +
> +#endif /* QC_MSM_CAMSS_CSIPHY_H */

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@....fi	XMPP: sailus@...iisi.org.uk

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