Date:   Mon, 26 Oct 2020 11:39:43 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devel@...verdev.osuosl.org, linux-sunxi@...glegroups.com,
        Hans Verkuil <hverkuil@...all.nl>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Helen Koike <helen.koike@...labora.com>,
        Vinod Koul <vkoul@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Chen-Yu Tsai <wens@...e.org>, Rob Herring <robh+dt@...nel.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Yong Deng <yong.deng@...ewell.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        kevin.lhopital@...mail.com
Subject: Re: [PATCH 08/14] media: sunxi: Add support for the A31 MIPI CSI-2
 controller

On Fri, Oct 23, 2020 at 07:45:40PM +0200, Paul Kocialkowski wrote:
> +static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> +{
> +	struct sun6i_mipi_csi2_video *video =
> +		sun6i_mipi_csi2_subdev_video(subdev);
> +	struct sun6i_mipi_csi2_dev *cdev = sun6i_mipi_csi2_video_dev(video);
> +	struct v4l2_subdev *remote_subdev = video->remote_subdev;
> +	struct v4l2_fwnode_bus_mipi_csi2 *bus_mipi_csi2 =
> +		&video->endpoint.bus.mipi_csi2;
> +	union phy_configure_opts dphy_opts = { 0 };
> +	struct phy_configure_opts_mipi_dphy *dphy_cfg = &dphy_opts.mipi_dphy;
> +	struct regmap *regmap = cdev->regmap;
> +	struct v4l2_ctrl *ctrl;
> +	unsigned int lanes_count;
> +	unsigned int bpp;
> +	unsigned long pixel_rate;
> +	u8 data_type = 0;
> +	u32 version = 0;
> +	/* Initialize to 0 to use both in disable label (ret != 0) and off. */
> +	int ret = 0;
> +
> +	if (!remote_subdev)
> +		return -ENODEV;
> +
> +	if (!on) {
> +		v4l2_subdev_call(remote_subdev, video, s_stream, 0);
> +
> +disable:
> +		regmap_update_bits(regmap, SUN6I_MIPI_CSI2_CTL_REG,
> +				   SUN6I_MIPI_CSI2_CTL_EN, 0);
> +
> +		phy_power_off(cdev->dphy);
> +
> +		return ret;

This would be better as a separate function.  (I hate backwards gotos
like this.)

> +	}
> +
> +	switch (video->mbus_code) {
> +	case MEDIA_BUS_FMT_SBGGR8_1X8:
> +	case MEDIA_BUS_FMT_SGBRG8_1X8:
> +	case MEDIA_BUS_FMT_SGRBG8_1X8:
> +	case MEDIA_BUS_FMT_SRGGB8_1X8:
> +		data_type = MIPI_CSI2_DATA_TYPE_RAW8;
> +		bpp = 8;
> +		break;
> +	case MEDIA_BUS_FMT_SBGGR10_1X10:
> +	case MEDIA_BUS_FMT_SGBRG10_1X10:
> +	case MEDIA_BUS_FMT_SGRBG10_1X10:
> +	case MEDIA_BUS_FMT_SRGGB10_1X10:
> +		data_type = MIPI_CSI2_DATA_TYPE_RAW10;
> +		bpp = 10;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	/* Sensor pixel rate */
> +
> +	ctrl = v4l2_ctrl_find(remote_subdev->ctrl_handler, V4L2_CID_PIXEL_RATE);
> +	if (!ctrl) {
> +		dev_err(cdev->dev,
> +			"%s: no MIPI CSI-2 pixel rate from the sensor\n",
> +			__func__);
> +		return -ENODEV;
> +	}
> +
> +	pixel_rate = (unsigned long)v4l2_ctrl_g_ctrl_int64(ctrl);
> +	if (!pixel_rate) {
> +		dev_err(cdev->dev,
> +			"%s: zero MIPI CSI-2 pixel rate from the sensor\n",
> +			__func__);
> +		return -ENODEV;
> +	}
> +
> +	/* D-PHY configuration */
> +
> +	lanes_count = bus_mipi_csi2->num_data_lanes;
> +	phy_mipi_dphy_get_default_config(pixel_rate, bpp, lanes_count,
> +					 dphy_cfg);
> +
> +
> +	/*
> +	 * Note that our hardware is using DDR, which is not taken in account by
> +	 * phy_mipi_dphy_get_default_config when calculating hs_clk_rate from
> +	 * the pixel rate, lanes count and bpp.
> +	 *
> +	 * The resulting clock rate is basically the symbol rate over the whole
> +	 * link. The actual clock rate is calculated with division by two since
> +	 * DDR samples both on rising and falling edges.
> +	 */
> +
> +	dev_dbg(cdev->dev, "A31 MIPI CSI-2 config:\n");
> +	dev_dbg(cdev->dev, "%ld pixels/s, %u bits/pixel, %lu Hz clock\n",
> +		pixel_rate, bpp, dphy_cfg->hs_clk_rate / 2);
> +
> +	ret = 0;
> +	ret |= phy_reset(cdev->dphy);
> +	ret |= phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
> +				PHY_MIPI_DPHY_SUBMODE_RX);
> +	ret |= phy_configure(cdev->dphy, &dphy_opts);
> +
> +	if (ret) {
> +		dev_err(cdev->dev, "failed to setup MIPI D-PHY\n");
> +		return ret;
> +	}
> +
> +	ret = phy_power_on(cdev->dphy);
> +	if (ret) {
> +		dev_err(cdev->dev, "failed to power on MIPI D-PHY\n");
> +		return ret;
> +	}
> +
> +	/* MIPI CSI-2 controller setup */
> +
> +	/*
> +	 * The enable flow in the Allwinner BSP is a bit different: the enable
> +	 * and reset bits are set together before starting the CSI controller.
> +	 *
> +	 * In mainline we enable the CSI controller first (due to subdev logic).
> +	 * One reliable way to make this work is to deassert reset, configure
> +	 * registers and enable the controller when everything's ready.
> +	 *
> +	 * However, reading the version appears necessary for it to work
> +	 * reliably. Replacing it with a delay doesn't do the trick.
> +	 */
> +	regmap_write(regmap, SUN6I_MIPI_CSI2_CTL_REG,
> +		     SUN6I_MIPI_CSI2_CTL_RESET_N |
> +		     SUN6I_MIPI_CSI2_CTL_VERSION_EN |
> +		     SUN6I_MIPI_CSI2_CTL_UNPK_EN);
> +
> +	regmap_read(regmap, SUN6I_MIPI_CSI2_VERSION_REG, &version);
> +
> +	regmap_update_bits(regmap, SUN6I_MIPI_CSI2_CTL_REG,
> +				   SUN6I_MIPI_CSI2_CTL_VERSION_EN, 0);
> +
> +	dev_dbg(cdev->dev, "A31 MIPI CSI-2 version: %04x\n", version);
> +
> +	regmap_write(regmap, SUN6I_MIPI_CSI2_CFG_REG,
> +		     SUN6I_MIPI_CSI2_CFG_CHANNEL_MODE(1) |
> +		     SUN6I_MIPI_CSI2_CFG_LANE_COUNT(lanes_count));
> +
> +	regmap_write(regmap, SUN6I_MIPI_CSI2_VCDT_RX_REG,
> +		     SUN6I_MIPI_CSI2_VCDT_RX_CH_VC(3, 3) |
> +		     SUN6I_MIPI_CSI2_VCDT_RX_CH_VC(2, 2) |
> +		     SUN6I_MIPI_CSI2_VCDT_RX_CH_VC(1, 1) |
> +		     SUN6I_MIPI_CSI2_VCDT_RX_CH_VC(0, 0) |
> +		     SUN6I_MIPI_CSI2_VCDT_RX_CH_DT(0, data_type));
> +
> +	regmap_update_bits(regmap, SUN6I_MIPI_CSI2_CTL_REG,
> +			   SUN6I_MIPI_CSI2_CTL_EN, SUN6I_MIPI_CSI2_CTL_EN);
> +
> +	ret = v4l2_subdev_call(remote_subdev, video, s_stream, 1);
> +	if (ret)
> +		goto disable;
> +
> +	return 0;
> +}
> +

[ snip ]

> +static int sun6i_mipi_csi2_v4l2_setup(struct sun6i_mipi_csi2_dev *cdev)
> +{
> +	struct sun6i_mipi_csi2_video *video = &cdev->video;
> +	struct v4l2_subdev *subdev = &video->subdev;
> +	struct v4l2_async_notifier *notifier = &video->notifier;
> +	struct fwnode_handle *handle;
> +	struct v4l2_fwnode_endpoint *endpoint;
> +	int ret;
> +
> +	/* Subdev */
> +
> +	v4l2_subdev_init(subdev, &sun6i_mipi_csi2_subdev_ops);
> +	subdev->dev = cdev->dev;
> +	strscpy(subdev->name, MODULE_NAME, sizeof(subdev->name));
> +	v4l2_set_subdevdata(subdev, cdev);
> +
> +	/* Entity */
> +
> +	subdev->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> +	subdev->entity.ops = &sun6i_mipi_csi2_entity_ops;
> +
> +	/* Pads */
> +
> +	video->pads[0].flags = MEDIA_PAD_FL_SINK;
> +	video->pads[1].flags = MEDIA_PAD_FL_SOURCE;
> +
> +	ret = media_entity_pads_init(&subdev->entity, 2, video->pads);
> +	if (ret)
> +		return ret;
> +
> +	/* Endpoint */
> +
> +	handle = fwnode_graph_get_endpoint_by_id(dev_fwnode(cdev->dev), 0, 0,
> +						 FWNODE_GRAPH_ENDPOINT_NEXT);
> +	if (!handle)
> +		goto error_media_entity;

Missing error code.

> +
> +	endpoint = &video->endpoint;
> +	endpoint->bus_type = V4L2_MBUS_CSI2_DPHY;
> +
> +	ret = v4l2_fwnode_endpoint_parse(handle, endpoint);
> +	fwnode_handle_put(handle);
> +	if (ret)
> +		goto error_media_entity;
> +
> +	/* Notifier */
> +
> +	v4l2_async_notifier_init(notifier);
> +
> +	ret = v4l2_async_notifier_add_fwnode_remote_subdev(notifier, handle,
> +							   &video->subdev_async);
> +	if (ret)
> +		goto error_media_entity;
> +
> +	video->notifier.ops = &sun6i_mipi_csi2_notifier_ops;
> +
> +	ret = v4l2_async_subdev_notifier_register(subdev, notifier);
> +	if (ret < 0)
> +		goto error_notifier;
> +
> +	/* Subdev */
> +
> +	ret = v4l2_async_register_subdev(subdev);
> +	if (ret < 0)
> +		goto error_notifier_registered;
> +
> +	return 0;
> +
> +error_notifier_registered:
> +	v4l2_async_notifier_unregister(notifier);
> +error_notifier:
> +	v4l2_async_notifier_cleanup(notifier);
> +error_media_entity:
> +	media_entity_cleanup(&subdev->entity);
> +
> +	return ret;
> +}

regards,
dan carpenter

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