Hi,
On Sat, Nov 10, 2018 at 01:16:51PM +0200, Laurent Pinchart wrote:
> The DSS DT node contains children that describe the DSS components
> (DISPC and internal encoders). Each of those components is handled by a
> platform driver, and thus needs to be backed by a platform device.
>
> The corresponding platform devices are created in mach-omap2 code by a
> call to of_platform_populate(). While this approach has worked so far,
> it doesn't model the hardware architecture very well, as it creates
> child devices before the parent is ready to handle them. This would be
> akin to creating I2C slaves before the I2C master is available.
>
> The task can be easily performed in the omapdss driver code instead,
> simplifying mach-omap2 code. We however can't remove the mach-omap2 code
> completely as the omap2fb driver still depends on it, but we can move it
> to the omap2fb-specific section, where it can stay until the omap2fb
> driver gets removed.
>
> This has the added benefit of not allowing DSS components to probe
> before the DSS itself, which led to runtime PM issues when the DSS probe
> is deferred.
>
> Fixes: 27d624527d99 ("drm/omap: dss: Acquire next dssdev at probe time")
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
-- Sebastian
> arch/arm/mach-omap2/display.c | 111 ++++++++++++++----------------
> drivers/gpu/drm/omapdrm/dss/dss.c | 11 ++-
> 2 files changed, 63 insertions(+), 59 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
> index 9500b6e27380..f86b72d1d59e 100644
> --- a/arch/arm/mach-omap2/display.c
> +++ b/arch/arm/mach-omap2/display.c
> @@ -209,11 +209,61 @@ static int __init omapdss_init_fbdev(void)
>
> return 0;
> }
> -#else
> -static inline int omapdss_init_fbdev(void)
> +
> +static const char * const omapdss_compat_names[] __initconst = {
> + "ti,omap2-dss",
> + "ti,omap3-dss",
> + "ti,omap4-dss",
> + "ti,omap5-dss",
> + "ti,dra7-dss",
> +};
> +
> +static struct device_node * __init omapdss_find_dss_of_node(void)
> {
> - return 0;
> + struct device_node *node;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(omapdss_compat_names); ++i) {
> + node = of_find_compatible_node(NULL, NULL,
> + omapdss_compat_names[i]);
> + if (node)
> + return node;
> + }
> +
> + return NULL;
> }
> +
> +static int __init omapdss_init_of(void)
> +{
> + int r;
> + struct device_node *node;
> + struct platform_device *pdev;
> +
> + /* only create dss helper devices if dss is enabled in the .dts */
> +
> + node = omapdss_find_dss_of_node();
> + if (!node)
> + return 0;
> +
> + if (!of_device_is_available(node))
> + return 0;
> +
> + pdev = of_find_device_by_node(node);
> +
> + if (!pdev) {
> + pr_err("Unable to find DSS platform device\n");
> + return -ENODEV;
> + }
> +
> + r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> + if (r) {
> + pr_err("Unable to populate DSS submodule devices\n");
> + return r;
> + }
> +
> + return omapdss_init_fbdev();
> +}
> +omap_device_initcall(omapdss_init_of);
> #endif /* CONFIG_FB_OMAP2 */
>
> static void dispc_disable_outputs(void)
> @@ -361,58 +411,3 @@ int omap_dss_reset(struct omap_hwmod *oh)
>
> return r;
> }
> -
> -static const char * const omapdss_compat_names[] __initconst = {
> - "ti,omap2-dss",
> - "ti,omap3-dss",
> - "ti,omap4-dss",
> - "ti,omap5-dss",
> - "ti,dra7-dss",
> -};
> -
> -static struct device_node * __init omapdss_find_dss_of_node(void)
> -{
> - struct device_node *node;
> - int i;
> -
> - for (i = 0; i < ARRAY_SIZE(omapdss_compat_names); ++i) {
> - node = of_find_compatible_node(NULL, NULL,
> - omapdss_compat_names[i]);
> - if (node)
> - return node;
> - }
> -
> - return NULL;
> -}
> -
> -static int __init omapdss_init_of(void)
> -{
> - int r;
> - struct device_node *node;
> - struct platform_device *pdev;
> -
> - /* only create dss helper devices if dss is enabled in the .dts */
> -
> - node = omapdss_find_dss_of_node();
> - if (!node)
> - return 0;
> -
> - if (!of_device_is_available(node))
> - return 0;
> -
> - pdev = of_find_device_by_node(node);
> -
> - if (!pdev) {
> - pr_err("Unable to find DSS platform device\n");
> - return -ENODEV;
> - }
> -
> - r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> - if (r) {
> - pr_err("Unable to populate DSS submodule devices\n");
> - return r;
> - }
> -
> - return omapdss_init_fbdev();
> -}
> -omap_device_initcall(omapdss_init_of);
> diff --git a/drivers/gpu/drm/omapdrm/dss/dss.c b/drivers/gpu/drm/omapdrm/dss/dss.c
> index 1aaf260aa9b8..7553c7fc1c45 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dss.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dss.c
> @@ -1484,16 +1484,23 @@ static int dss_probe(struct platform_device *pdev)
> dss);
>
> /* Add all the child devices as components. */
> + r = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> + if (r)
> + goto err_uninit_debugfs;
> +
> omapdss_gather_components(&pdev->dev);
>
> device_for_each_child(&pdev->dev, &match, dss_add_child_component);
>
> r = component_master_add_with_match(&pdev->dev, &dss_component_ops, match);
> if (r)
> - goto err_uninit_debugfs;
> + goto err_of_depopulate;
>
> return 0;
>
> +err_of_depopulate:
> + of_platform_depopulate(&pdev->dev);
> +
> err_uninit_debugfs:
> dss_debugfs_remove_file(dss->debugfs.clk);
> dss_debugfs_remove_file(dss->debugfs.dss);
> @@ -1522,6 +1529,8 @@ static int dss_remove(struct platform_device *pdev)
> {
> struct dss_device *dss = platform_get_drvdata(pdev);
>
> + of_platform_depopulate(&pdev->dev);
> +
> component_master_del(&pdev->dev, &dss_component_ops);
>
> dss_debugfs_remove_file(dss->debugfs.clk);
> --
> Regards,
>
> Laurent Pinchart
>
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