Messages in this thread | | | Date | Mon, 23 Mar 2015 16:33:26 +0530 | From | Archit Taneja <> | Subject | Re: [PATCH 3/4] drm/msm: Initial add DSI connector support |
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Hi Hai,
On 03/19/2015 02:35 AM, hali@codeaurora.org wrote: > Hi Archit, > > Thanks for your comments. Please see my response for some comments below. > Comments without response will be addressed in patch version 2. I will > wait for other comments if any to push patch V2. > >>> +static int dsi_gpio_init(struct msm_dsi_host *msm_host) >>> +{ >>> + int ret; >>> + >>> + msm_host->disp_en_gpio = devm_gpiod_get(&msm_host->pdev->dev, >>> + "disp-enable"); >>> + if (IS_ERR(msm_host->disp_en_gpio)) { >>> + pr_warn("%s: cannot get disp-enable-gpios %ld\n", >>> + __func__, PTR_ERR(msm_host->disp_en_gpio)); >>> + msm_host->disp_en_gpio = NULL; >>> + } >>> + if (msm_host->disp_en_gpio) { >>> + ret = gpiod_direction_output(msm_host->disp_en_gpio, 0); >>> + if (ret) { >>> + pr_err("cannot set dir to disp-en-gpios %d\n", ret); >>> + return ret; >>> + } >>> + } >>> + >>> + msm_host->te_gpio = devm_gpiod_get(&msm_host->pdev->dev, "disp-te"); >>> + if (IS_ERR(msm_host->te_gpio)) { >>> + pr_warn("%s: cannot get disp-te-gpios %ld\n", >>> + __func__, PTR_ERR(msm_host->te_gpio)); >> >> Video mode panels won't have te_gpio, we could probably make this >> pr_debug() >> >>> + msm_host->te_gpio = NULL; >>> + } >>> + >>> + if (msm_host->te_gpio) { >>> + ret = gpiod_direction_input(msm_host->te_gpio); >>> + if (ret) { >>> + pr_err("%s: cannot set dir to disp-te-gpios, %d\n", >>> + __func__, ret); >>> + return ret; >>> + } >>> + } >> >> These gpios currently need to be declared under the dsi DT node. Even if >> these are controlled via the dsi host, the gpios should still come under >> the panel DT node. >> >> We shout get the panel's of_node here and look for these. >> > >>> +static void dsi_sw_reset(struct msm_dsi_host *msm_host) >>> +{ >>> + dsi_write(msm_host, REG_DSI_CLK_CTRL, >>> + DSI_CLK_CTRL_AHBS_HCLK_ON | DSI_CLK_CTRL_AHBM_SCLK_ON | >>> + DSI_CLK_CTRL_PCLK_ON | DSI_CLK_CTRL_DSICLK_ON | >>> + DSI_CLK_CTRL_BYTECLK_ON | DSI_CLK_CTRL_ESCCLK_ON | >>> + DSI_CLK_CTRL_FORCE_ON_DYN_AHBM_HCLK); >> >> The same 7 bits seem to be set elsewhere, maybe make this a macro >> DSI_ENABLE_CLKS or something similar? >> > >>> +int msm_dsi_host_init(struct msm_dsi *msm_dsi) >>> +{ >>> + struct msm_dsi_host *msm_host = NULL; >>> + struct platform_device *pdev = msm_dsi->pdev; >>> + int ret = 0; >>> + >>> + msm_host = devm_kzalloc(&pdev->dev, sizeof(*msm_host), GFP_KERNEL); >>> + if (!msm_host) { >>> + pr_err("%s: FAILED: cannot alloc dsi host\n", >>> + __func__); >>> + ret = -ENOMEM; >>> + goto fail; >>> + } >>> + >>> + ret = of_property_read_u32(pdev->dev.of_node, >>> + "cell-index", &msm_host->id); >> >> retrieving the instance number of a peripheral via a DT property like >> 'cell-index' has been debated quite a bit in the past. I suppose it's >> not the best thing to do. >> >> However, since the DSI instances in MDSS aren't completely identical(one >> acts a master and other slave in dual dsi mode), maybe we can get away >> with having a property like "qcom,dsi-master;", and that can be further >> used to identify whether this node is DSI_0 or DSI_1 >> > > 2 DSIs are not always master-slave mode. It is possible that a single > panel is connected to any of the hosts, or 2 panels are controlled > independently. If 'cell-index' is not allowed to specify the instance > number, i would prefer to have a simple property like > "qcom,dsi-host-index".
Okay, thanks for that clarification.
> >>> +int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer) >>> +{ >>> + struct msm_dsi_host *msm_host = to_msm_dsi_host(host); >>> + struct device_node *node; >>> + int ret; >>> + >>> + /* Register mipi dsi host */ >>> + if (!msm_host->registered) { >>> + host->dev = &msm_host->pdev->dev; >>> + host->ops = &dsi_host_ops; >>> + ret = mipi_dsi_host_register(host); >>> + if (ret) >>> + return ret; >>> + >>> + msm_host->registered = true; >>> + >>> + /* If the panel driver has not been probed after host register, >>> + * we should defer the host's probe. >>> + * It makes sure panel is connected when fbcon detects >>> + * connector status and gets the proper display mode to >>> + * create framebuffer. >>> + */ >>> + if (check_defer) { >>> + node = of_parse_phandle(msm_host->pdev->dev.of_node, >>> + "qcom,panel", 0); >>> + if (node) { >>> + if (!of_drm_find_panel(node)) >>> + return -EPROBE_DEFER; >>> + } >>> + } >>> + } >> >> We might have to defer probe multiple times before another dependency is >> met. The above approach will let the driver defer only once without the >> panel driver registered. During the second probe attempt, we'd just >> return since 'msm_host->registered' would be true. >> >> I think we could move this check to end of dsi_init(). >> > > Once probe deferred, the private data structures will be cleaned up and > re-allocated at the next probe. It should support multiple times probe > deferral.
Ah right! I forgot about that. However, I don't think the panel would be a phandle entry under the dsi device node, right? Also, "qcom,panel" seems more like a compatible string to me. Should it rather be:
node = of_get_child_by_name(msm_host->pdev->dev.of_node, "panel"); if (node) ... ...
> >>> +static int dsi_mgr_connector_mode_valid(struct drm_connector >>> *connector, >>> + struct drm_display_mode *mode) >>> +{ >>> + int id = dsi_mgr_connector_get_id(connector); >>> + struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id); >>> + struct drm_encoder *encoder = >>> + (msm_dsi->panel_flags & MIPI_DSI_MODE_VIDEO) ? >>> + msm_dsi->base.encoders[MSM_DSI_VIDEO_ENCODER_ID] : >>> + msm_dsi->base.encoders[MSM_DSI_CMD_ENCODER_ID]; >> >> Maybe you could make a helper 'msm_dsi_get_encoder(msm_dsi)' out of >> this? It seems to be used elsewhere too. >> > >>> +int msm_dsi_manager_register(struct msm_dsi *msm_dsi) >>> +{ >>> + struct msm_dsi_manager *msm_dsim = &msm_dsim_glb; >>> + int id = msm_dsi->id; >>> + struct msm_dsi *other_dsi = dsi_mgr_get_other_dsi(id); >>> + int ret; >>> + >>> + if (id > DSI_MAX) { >>> + pr_err("%s: invalid id %d\n", __func__, id); >>> + return -EINVAL; >>> + } >>> + >>> + if (msm_dsim->dsi[id]) { >>> + pr_err("%s: dsi%d already registered\n", __func__, id); >>> + return -EBUSY; >>> + } >>> + >>> + msm_dsim->dsi[id] = msm_dsi; >>> + >>> + ret = dsi_mgr_parse_dual_panel(msm_dsi->pdev->dev.of_node, id); >>> + if (ret) { >>> + pr_err("%s: failed to parse dual panel info\n", __func__); >>> + return ret; >>> + } >>> + >>> + if (!IS_DUAL_PANEL()) { >>> + ret = msm_dsi_host_register(msm_dsi->host, true); >>> + } else if (!other_dsi) { >>> + return 0; >>> + } else { >>> + struct msm_dsi *mdsi = IS_MASTER_PANEL(id) ? >>> + msm_dsi : other_dsi; >>> + struct msm_dsi *sdsi = IS_MASTER_PANEL(id) ? >>> + other_dsi : msm_dsi; >>> + /* Register slave host first, so that slave DSI device >>> + * has a chance to probe, and do not block the master >>> + * DSI device's probe. >>> + * Also, do not check defer for the slave host, >>> + * because only master DSI device adds the panel to global >>> + * panel list. The panel's device is the master DSI device. >>> + */ >>> + ret = msm_dsi_host_register(sdsi->host, false); >>> + if (ret) >>> + return ret; >>> + ret = msm_dsi_host_register(mdsi->host, true); >>> + } >>> + >>> + return ret; >>> +} >> >> The dual panel checks in these functions are quite intrusive at the >> moment. We'd use DSI later where there won't be a panel at all. That >> would result in ever more complicated checks. >> >> Is it possible to separate out the dual panel functionality such that it >> becomes cleaner? >> >> For example msm_dsi_manager_phy_disable can look like: >> >> void msm_dsi_manager_phy_disable(int id) >> { >> ... >> ... >> >> if (msm_dual_dsi_mode()) >> msm_dual_dsi_phy_disable(id); >> else >> msm_dsi_phy_disable(phy); >> >> ... >> } >> >> There might be repetition of some code between the normal and dual mode >> case, but it will make things quite legible. >> > > I think even we separate out the dual DSI functionality, we still need to > check dual DSI mode like the code above. The purpose of dsi_manager module > is to centralize dual DSI handler, so there has to be many checks. > > The current code should work with different cases, > single-host-single-panel, dual-host-single-panel, dual-host-dual-panel and > dual-host-independent-two-panels. If there is no panel for the host, we > will report disconnected connector. If we want to convert to other > interface type, i would prefer to have a fake dsi panel driver, to follow > the current framework. >
I think it will be a bit hard to incorporate fake panel support. I liked what's done in exynos/exynos_dp_core.c:
The driver figures out if the device node supports a panel connected via a bridge, or a DP connector. Based on this info, it registers either a bridge driver, or a usual DP connector.
I think it is fine to get this pulled as is. We can think later about whether the above or a fake panel approach would make more sense.
Thanks, Archit
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