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Message-ID: <4331afd6-3891-2dd5-b5b8-2ffc5d1cbed5@lucaceresoli.net>
Date: Tue, 21 Apr 2020 12:29:52 +0200
From: Luca Ceresoli <luca@...aceresoli.net>
To: Vishal Sagar <vishal.sagar@...inx.com>,
Hyun Kwon <hyunk@...inx.com>,
laurent.pinchart@...asonboard.com, mchehab@...nel.org,
robh+dt@...nel.org, mark.rutland@....com,
Michal Simek <michals@...inx.com>, linux-media@...r.kernel.org,
devicetree@...r.kernel.org, hans.verkuil@...co.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Dinesh Kumar <dineshk@...inx.com>,
Sandip Kothari <sandipk@...inx.com>,
Jacopo Mondi <jacopo@...ndi.org>
Cc: Hyun Kwon <hyun.kwon@...inx.com>
Subject: Re: [PATCH v11 2/2] media: v4l: xilinx: Add Xilinx MIPI CSI-2 Rx
Subsystem driver
Hi Vishal,
thanks for having resumed this patchset!
On 09/04/20 21:44, Vishal Sagar wrote:
[...]
> +static int xcsi2rxss_parse_of(struct xcsi2rxss_state *xcsi2rxss)
> +{
> + struct xcsi2rxss_core *core = &xcsi2rxss->core;
> + struct device_node *node = xcsi2rxss->core.dev->of_node;
Can be simplified as:
struct device_node *node = core.dev->of_node;
> + unsigned int nports, irq;
> + bool en_csi_v20, vfb;
> + int ret;
> +
> + en_csi_v20 = of_property_read_bool(node, "xlnx,en-csi-v2-0");
> + if (en_csi_v20)
> + core->en_vcx = of_property_read_bool(node, "xlnx,en-vcx");
> +
> + core->enable_active_lanes =
> + of_property_read_bool(node, "xlnx,en-active-lanes");
> +
> + ret = of_property_read_u32(node, "xlnx,csi-pxl-format",
> + &core->datatype);
> + if (ret < 0) {
> + dev_err(core->dev, "missing xlnx,csi-pxl-format property\n");
> + return ret;
> + }
> +
> + switch (core->datatype) {
> + case XCSI_DT_YUV4228B:
> + case XCSI_DT_RGB444:
> + case XCSI_DT_RGB555:
> + case XCSI_DT_RGB565:
> + case XCSI_DT_RGB666:
> + case XCSI_DT_RGB888:
> + case XCSI_DT_RAW6:
> + case XCSI_DT_RAW7:
> + case XCSI_DT_RAW8:
> + case XCSI_DT_RAW10:
> + case XCSI_DT_RAW12:
> + case XCSI_DT_RAW14:
> + break;
> + case XCSI_DT_YUV42210B:
> + case XCSI_DT_RAW16:
> + case XCSI_DT_RAW20:
> + if (!en_csi_v20) {
> + ret = -EINVAL;
> + dev_dbg(core->dev, "enable csi v2 for this pixel format");
> + }
> + break;
> + default:
> + ret = -EINVAL;
> + }
> + if (ret < 0) {
> + dev_err(core->dev, "invalid csi-pxl-format property!\n");
> + return ret;
> + }
> +
> + vfb = of_property_read_bool(node, "xlnx,vfb");
> + if (!vfb) {
> + dev_err(core->dev, "failed as VFB is disabled!\n");
> + return -EINVAL;
> + }
> +
> + for (nports = 0; nports < XCSI_MEDIA_PADS; nports++) {
> + struct fwnode_handle *ep;
> + struct v4l2_fwnode_endpoint vep = {
> + .bus_type = V4L2_MBUS_CSI2_DPHY
> + };
> +
> + ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(core->dev),
> + nports, 0,
> + FWNODE_GRAPH_ENDPOINT_NEXT);
> + if (!ep)
> + break;
> + /*
> + * since first port is sink port and it contains
> + * all info about data-lanes and cfa-pattern,
> + * don't parse second port but only check if exists
> + */
> + if (nports == XVIP_PAD_SOURCE) {
> + dev_dbg(core->dev, "no need to parse source port");
> + fwnode_handle_put(ep);
> + continue;
> + }
> +
> + ret = v4l2_fwnode_endpoint_parse(ep, &vep);
> + if (ret) {
> + dev_err(core->dev, "error parsing sink port");
> + fwnode_handle_put(ep);
> + return ret;
> + }
> +
> + dev_dbg(core->dev, "port %d bus type = %d\n", nports,
> + vep.bus_type);
> +
> + if (vep.bus_type == V4L2_MBUS_CSI2_DPHY) {
> + dev_dbg(core->dev, "base.port = %d base.id = %d\n",
> + vep.base.port, vep.base.id);
> +
> + dev_dbg(core->dev, "mipi number lanes = %d\n",
> + vep.bus.mipi_csi2.num_data_lanes);
> +
> + core->max_num_lanes =
> + vep.bus.mipi_csi2.num_data_lanes;
> + }
> + fwnode_handle_put(ep);
> + }
> +
> + if (nports != XCSI_MEDIA_PADS) {
> + dev_err(core->dev, "invalid number of ports %u\n", nports);
> + return -EINVAL;
> + }
> +
> + /* Register interrupt handler */
> + irq = irq_of_parse_and_map(node, 0);
> + ret = devm_request_irq(core->dev, irq, xcsi2rxss_irq_handler,
> + IRQF_SHARED, "xilinx-csi2rxss", xcsi2rxss);
> + if (ret) {
> + dev_err(core->dev, "Err = %d Interrupt handler reg failed!\n",
> + ret);
> + return ret;
> + }
When using this driver I have changed this to a threaded IRQ, moving
most of the management out of interrupt context. The patch is super
simple and it works fine, for my use case at least. Do you think a
strict IRQ is really needed for some reason?
> + xcsi2rxss_log_ipconfig(xcsi2rxss);
> +
> + return 0;
This function references 'core->dev' a lot of times, so I'd rather add
at the top of the function:
struct device * const dev = &pdev->dev;
and then use simply 'dev' everywhere. This would keep lines shorter and
more readable. It is also handy when copying/moving a line of code from
one function to another if all of them have 'dev' called the same way so
I tend to do use this pattern often.
> +}
> +
> +static int xcsi2rxss_probe(struct platform_device *pdev)
> +{
> + struct v4l2_subdev *subdev;
> + struct xcsi2rxss_state *xcsi2rxss;
> + struct xcsi2rxss_core *core;
> + struct resource *res;
> + int num_clks = ARRAY_SIZE(xcsi2rxss_clks);
> + int ret;
> +
> + xcsi2rxss = devm_kzalloc(&pdev->dev, sizeof(*xcsi2rxss), GFP_KERNEL);
> + if (!xcsi2rxss)
> + return -ENOMEM;
> +
> + core = &xcsi2rxss->core;
> + core->dev = &pdev->dev;
This function references 'dev' many times, sometimes as &pdev->dev,
thers as 'core->dev', thus as above why not adding at the top of the
function:
struct device * const dev = &pdev->dev;
and simplify code using 'dev' always?
> + core->clks = devm_kmemdup(core->dev, xcsi2rxss_clks,
> + sizeof(xcsi2rxss_clks), GFP_KERNEL);
> + if (!core->clks)
> + return -ENOMEM;
> +
> + /* Reset GPIO */
> + core->rst_gpio = devm_gpiod_get_optional(core->dev, "reset",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(core->rst_gpio)) {
> + if (PTR_ERR(core->rst_gpio) != -EPROBE_DEFER)
> + dev_err(core->dev, "Video Reset GPIO not setup in DT");
> + return PTR_ERR(core->rst_gpio);
> + }
> +
> + mutex_init(&xcsi2rxss->lock);
There are 3 'return' statements after this call, and mutex_destroy()
won't be called if they trigger. Ok, probably no real effect as
mutex_init() is just initializing data, but for the sake of well-written
code you can simply move mutex_init()...
> + ret = xcsi2rxss_parse_of(xcsi2rxss);
> + if (ret < 0)
> + return ret;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + core->iomem = devm_ioremap_resource(core->dev, res);
> + if (IS_ERR(core->iomem))
> + return PTR_ERR(core->iomem);
> +
> + ret = clk_bulk_get(core->dev, num_clks, core->clks);
> + if (ret)
> + return ret;
> +
> + ret = clk_bulk_prepare_enable(num_clks, core->clks);
> + if (ret)
> + goto err_clk_put;
...here.
> + if (core->rst_gpio) {
> + gpiod_set_value_cansleep(core->rst_gpio, 1);
> + /* minimum of 40 dphy_clk_200M cycles */
> + usleep_range(1, 2);
> + gpiod_set_value_cansleep(core->rst_gpio, 0);
> + }
--
Luca
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