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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=CmiOovZTt1y4cIWEfI47PRt3/MlHznjnR9cha/mAR4c=; b=H8fu0V9N4/+fIkXQIbzeTkg0pD5zhhhuenKCzm47qxsGZtaGboLL08paKR4SDT3vuJ DN0do3nvO6UP4txS3Zy9ZmsGfyRgpMlE/E2LrUTQvjDjvJkodTv1wl8WR585YyR2dn5G eEWX34FhrNaIRBSEy/28gDOTLTJ/a8GIOL6daUpiEm4RzTkBC5IITCSDTPtREjjKNxkF 6yUyQL7lW6OcGqh+lXwxeb0HhqKfK09Jqi61utdL/meOkdIJ4XQf8q05KcZ+cbeeHgUT jglvJM45JWH5ImacCs1njOvXVhWAWL8bkYH+UtnhqEzyJk1rq/K062uxWXP5lPagVA9u AY7g== X-Gm-Message-State: AOAM532LNicP0WgvgzNSUXFk+JXWHd+dWWEDOzIschf6e2YRwb2tvnDb ROeZk5N0vkMMl9IipYZbe+mHphq0SnemY2U= X-Google-Smtp-Source: ABdhPJxmH19nPmNYfApQCzFJa101DpD5Gzo0XYSrXU/wL13p/J/9TjYYqd+ffs7ankEM4mjnReGAXwID7O4vqfQ= X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:b45b:ca56:952a:2176]) (user=saravanak job=sendgmr) by 2002:a25:b9cf:: with SMTP id y15mr2035451ybj.110.1630713949404; Fri, 03 Sep 2021 17:05:49 -0700 (PDT) Date: Fri, 3 Sep 2021 17:05:41 -0700 In-Reply-To: <20210904000543.2019010-1-saravanak@google.com> Message-Id: <20210904000543.2019010-2-saravanak@google.com> Mime-Version: 1.0 References: <20210904000543.2019010-1-saravanak@google.com> X-Mailer: git-send-email 2.33.0.153.gba50c8fa24-goog Subject: [PATCH v3 1/2] drivers: bus: simple-pm-bus: Add support for probing simple bus only devices From: Saravana Kannan To: Russell King , Neil Armstrong , Geert Uytterhoeven , Magnus Damm , Tony Lindgren , Catalin Marinas , Will Deacon , Damien Le Moal Cc: Saravana Kannan , Ulf Hansson , Rob Herring , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-oxnas@groups.io, linux-renesas-soc@vger.kernel.org, linux-omap@vger.kernel.org, linux-riscv@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210903_170553_046241_B2E4F14D X-CRM114-Status: GOOD ( 20.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org fw_devlink could end up creating device links for bus only devices. However, bus only devices don't get probed and can block probe() or sync_state() [1] call backs of other devices. To avoid this, probe these devices using the simple-pm-bus driver. However, there are instances of devices that are not simple buses (they get probed by their specific drivers) that also list the "simple-bus" (or other bus only compatible strings) in their compatible property to automatically populate their child devices. We still want these devices to get probed by their specific drivers. So, we make sure this driver only probes devices that are only buses. [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ Signed-off-by: Saravana Kannan Tested-by: Saravana Kannan Reviewed-by: Ulf Hansson Tested-by: Ulf Hansson --- drivers/bus/simple-pm-bus.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c index 01a3d0cd08ed..3e086a9f34cb 100644 --- a/drivers/bus/simple-pm-bus.c +++ b/drivers/bus/simple-pm-bus.c @@ -13,11 +13,26 @@ #include #include - static int simple_pm_bus_probe(struct platform_device *pdev) { - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); - struct device_node *np = pdev->dev.of_node; + const struct device *dev = &pdev->dev; + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); + struct device_node *np = dev->of_node; + const struct of_device_id *match; + + match = of_match_device(dev->driver->of_match_table, dev); + + /* + * These are transparent bus devices (not simple-pm-bus matches) that + * have their child nodes populated automatically. So, don't need to + * do anything more. + */ + if (match && match->data) { + if (of_property_match_string(np, "compatible", match->compatible) == 0) + return 0; + else + return -ENODEV; + } dev_dbg(&pdev->dev, "%s\n", __func__); @@ -31,14 +46,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) static int simple_pm_bus_remove(struct platform_device *pdev) { + const void *data = of_device_get_match_data(&pdev->dev); + + if (data) + return 0; + dev_dbg(&pdev->dev, "%s\n", __func__); pm_runtime_disable(&pdev->dev); return 0; } +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ + static const struct of_device_id simple_pm_bus_of_match[] = { { .compatible = "simple-pm-bus", }, + { .compatible = "simple-bus", .data = ONLY_BUS }, + { .compatible = "simple-mfd", .data = ONLY_BUS }, + { .compatible = "isa", .data = ONLY_BUS }, + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);