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 24185C32753 for ; Wed, 14 Aug 2019 13:51:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC2E82084D for ; Wed, 14 Aug 2019 13:51:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565790696; bh=5au+uySpHKMUgQfB6f0HCtqCGXnnNO/toEwWtCgwQRU=; h=From:To:Cc:Subject:Date:List-ID:From; b=2axNNPpCELhgFlC/WieZM5HK/X+D89gQaKQ/AxWVkDdNUKGd6ZlUemia5syF6lNcs IF2RoqVEYyxdQ3YW182phkVObiHr9ejaN1ZW4ivItatKFduCeati1owYHfF6McscEj KPyL+017SYvllgU02TN9hPbs9YLVrcHpoKAvgsDM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728045AbfHNNve (ORCPT ); Wed, 14 Aug 2019 09:51:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:41720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726551AbfHNNve (ORCPT ); Wed, 14 Aug 2019 09:51:34 -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 843A02083B; Wed, 14 Aug 2019 13:51:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565790693; bh=5au+uySpHKMUgQfB6f0HCtqCGXnnNO/toEwWtCgwQRU=; h=From:To:Cc:Subject:Date:From; b=uiOtBSWig10yz+nCoVHu1if2OzdDV4ch9JMoPw/VNHRPt2QVN+cjR3yw23yu7Nk0k n4D4OupfIZWb0Yr/4pEZsqvU/mCDaDVbjwPIlSZqiA+rJIroAd6hE5Cx9npR8da1BE gpCVMkJlH1DrUn4oHZerUB2yp/Qg0rb4jJcPITqo= 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 Subject: [PATCHv4] drivers/amba: add reset control to amba bus probe Date: Wed, 14 Aug 2019 08:51:16 -0500 Message-Id: <20190814135116.10123-1-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 --- 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 | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 100e798a5c82..76a1cd56a1ab 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -18,6 +18,7 @@ #include #include #include +#include #include @@ -401,6 +402,26 @@ 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_get_shared_by_index(dev->dev.of_node, count - 1); + if (IS_ERR(rstc)) { + if (PTR_ERR(rstc) == -EPROBE_DEFER) + ret = -EPROBE_DEFER; + else + dev_err(&dev->dev, "Can't get amba reset!\n"); + break; + } + reset_control_deassert(rstc); + reset_control_put(rstc); + count--; + } /* * Read pid and cid based on size of resource -- 2.20.0