From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0767FC3A59F for ; Mon, 26 Aug 2019 15:44:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE29C20874 for ; Mon, 26 Aug 2019 15:43:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566834239; bh=IrvkLc5Ov+J/f8CttzyyWurWNwwmFftVjPaVQ+/Erqs=; h=From:To:Cc:Subject:Date:List-ID:From; b=LCVCdLbME2iE7igsVXya9Xyt3+YOD6hNPU05rDTf/4OVgcQBjcRQnhKf6v1OlzY8n a09pBibBcnvOiDrmTGwQjqXS9HYVFo5hFr7DtKBN0Hx4KPghKI2MVlSzzOIbl7SvW0 J02+vej6R5GDR2L9sxMOvzgmEWyXEQfi6xqZgBfc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729233AbfHZPn6 (ORCPT ); Mon, 26 Aug 2019 11:43:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:48634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727850AbfHZPnG (ORCPT ); Mon, 26 Aug 2019 11:43:06 -0400 Received: from localhost.localdomain (cpe-70-114-128-244.austin.res.rr.com [70.114.128.244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A973520874; Mon, 26 Aug 2019 15:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566834185; bh=IrvkLc5Ov+J/f8CttzyyWurWNwwmFftVjPaVQ+/Erqs=; h=From:To:Cc:Subject:Date:From; b=IZJ1OOsq+OVzE855bSAuMug6lB/iT8i5Ri6k3jzoxm0k9fjMH806zFUSijzubbxKx LWomNqyfpbzl/CajzHjJWwaZq1q2RieGA+rpC7ChH9xgyUAyuEAZKLEWq+Jmq/KAuC Hb1Pf9685vzxvdY3JJR7i48sLMFOfRvQBREZpqjU= From: Dinh Nguyen To: linux-kernel@vger.kernel.org Cc: dinguyen@kernel.org, devicetree@vger.kernel.org, robh@kernel.org, linux@armlinux.org.uk, frowand.list@gmail.com, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com, daniel.thompson@linaro.org, linus.walleij@linaro.org, manivannan.sadhasivam@linaro.org, linux-arm-kernel@lists.infradead.org, p.zabel@pengutronix.de Subject: [PATCHv5] drivers/amba: add reset control to amba bus probe Date: Mon, 26 Aug 2019 10:42:52 -0500 Message-Id: <20190826154252.22952-1-dinguyen@kernel.org> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The primecell controller on some SoCs, i.e. SoCFPGA, is held in reset by default. Until recently, the DMA controller was brought out of reset by the bootloader(i.e. U-Boot). But a recent change in U-Boot, the peripherals that are not used are held in reset and are left to Linux to bring them out of reset. Add a mechanism for getting the reset property and de-assert the primecell module from reset if found. This is a not a hard fail if the reset properti is not present in the device tree node, so the driver will continue to probe. Because there are different variants of the controller that may have multiple reset signals, the code will find all reset(s) specified and de-assert them. Signed-off-by: Dinh Nguyen Reviewed-by: Rob Herring --- v5: use of_reset_control_array_get_optional_shared() v4: cleaned up indentation in loop fix up a few checkpatch warnings add Reviewed-by: v3: add a reset_control_put() add error handling v2: move reset control to bus code find all reset properties and de-assert them --- drivers/amba/bus.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 100e798a5c82..f8a7cb74c3cf 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -18,6 +18,7 @@ #include #include #include +#include #include @@ -401,6 +402,24 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent) ret = amba_get_enable_pclk(dev); if (ret == 0) { u32 pid, cid; + int count; + struct reset_control *rstc; + + /* + * Find reset control(s) of the amba bus and de-assert them. + */ + count = reset_control_get_count(&dev->dev); + while (count > 0) { + rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node); + if (IS_ERR(rstc)) { + if (PTR_ERR(rstc) != -EPROBE_DEFER) + dev_err(&dev->dev, "Can't get amba reset!\n"); + return PTR_ERR(rstc); + } + reset_control_deassert(rstc); + reset_control_put(rstc); + count--; + } /* * Read pid and cid based on size of resource -- 2.20.0