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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i59fq-00038T-Qf; Tue, 03 Sep 2019 14:20:46 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i59fg-0002zM-7Y for linux-arm-kernel@lists.infradead.org; Tue, 03 Sep 2019 14:20:37 +0000 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 8E2BE22D6D; Tue, 3 Sep 2019 14:20:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567520434; bh=ygZcufiEa4tPWQUTLwsIpxN5DMwkrJv3yH0ESnqY4bQ=; h=From:To:Cc:Subject:Date:From; b=qO+VPZHZBEPdHZs0lMom5N2QPKLnYZHR+43Y+b8JoVwKXDe/uARpF7uubMFjc/1zV W0nmnVF9tczCPEB3PoaGXpuF+4g66gM/IwLC9kQ4O4Q1oufMBr7bE5JQXCsDKDrojN YKD1RvVt8Uv2xoMWNmjE5BR9bH2BB8INavDEF33Y= From: Dinh Nguyen To: linux-kernel@vger.kernel.org Subject: [PATCHv7] drivers/amba: add reset control to amba bus probe Date: Tue, 3 Sep 2019 09:12:15 -0500 Message-Id: <20190903141215.18283-1-dinguyen@kernel.org> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190903_072036_299188_035F5F86 X-CRM114-Status: GOOD ( 14.99 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robh@kernel.org, daniel.thompson@linaro.org, tony.luck@intel.com, manivannan.sadhasivam@linaro.org, keescook@chromium.org, devicetree@vger.kernel.org, linus.walleij@linaro.org, anton@enomsg.org, linux@armlinux.org.uk, dinguyen@kernel.org, p.zabel@pengutronix.de, ccross@android.com, frowand.list@gmail.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 Reviewed-by: Philipp Zabel Reviewed-by: Linus Walleij --- v7: added Philipp Zabel's Reviewed-by: v6: remove the need to reset_control_get_count as of_reset_control_array_get_optional_shared is already doing that 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 | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 100e798a5c82..f39f075abff9 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -18,6 +18,7 @@ #include #include #include +#include #include @@ -401,6 +402,19 @@ 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; + struct reset_control *rstc; + + /* + * Find reset control(s) of the amba bus and de-assert them. + */ + 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); /* * Read pid and cid based on size of resource