From patchwork Thu Oct 11 11:20:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Talel Shenhar X-Patchwork-Id: 982410 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=amazon.com header.i=@amazon.com header.b="n4X2Kc7w"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42W7n00XCkz9sC2 for ; Thu, 11 Oct 2018 22:20:36 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728481AbeJKSrQ (ORCPT ); Thu, 11 Oct 2018 14:47:16 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:24622 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726135AbeJKSrP (ORCPT ); Thu, 11 Oct 2018 14:47:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1539256828; x=1570792828; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=SmdW1HQJHQDSVi6FD1SR32M8B9tET1DkS7+cPRajD5c=; b=n4X2Kc7wHdWNdl+szwUAotBOtBcByjI2S5XbBWeDRhg+S4A2qi0XN4YF kPkLpRAdAvqUhX7fhWfHgd05nvdITJs/viIz+aVHh/gQf+6mt7v/cZqTX pBlixwjZvuuZLhn72ELH+cotAObA/Pa+Hth12zFEBUiFdkux1smvkmu1J 0=; X-IronPort-AV: E=Sophos;i="5.54,368,1534809600"; d="scan'208";a="362030531" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-6e2fc477.us-west-2.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 11 Oct 2018 11:20:26 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-2a-6e2fc477.us-west-2.amazon.com (8.14.7/8.14.7) with ESMTP id w9BBKOOr115508 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Thu, 11 Oct 2018 11:20:25 GMT Received: from EX13D01EUB001.ant.amazon.com (10.43.166.194) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 11 Oct 2018 11:20:25 +0000 Received: from udc4a3e82dbc15a031435.hfa14.amazon.com (10.43.161.25) by EX13D01EUB001.ant.amazon.com (10.43.166.194) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 11 Oct 2018 11:20:19 +0000 From: Talel Shenhar To: , , , , , CC: , , , , David Woodhouse Subject: [PATCH 1/2] dt-bindings: spi: dw: add compatible for Amazon's Alpine spi controller Date: Thu, 11 Oct 2018 14:20:06 +0300 Message-ID: <1539256807-25676-1-git-send-email-talel@amazon.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1539209339.1944.23.camel@impinj.com> References: <1539209339.1944.23.camel@impinj.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.25] X-ClientProxiedBy: EX13D08UWC004.ant.amazon.com (10.43.162.90) To EX13D01EUB001.ant.amazon.com (10.43.166.194) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This compatible adds the ability for dw spi controller driver to work with the dw spi controller found on Alpine chips. The dw spi controller has an auto-deselect of Chip-Select, in case there is no data inside the Tx FIFO. While working on platforms with Alpine chips, auto-deselect mode causes an issue for some spi devices that can't handle the Chip-Select deselect in the middle of a transaction. It is a normal behavior for a Tx FIFO to be empty in the middle of a transaction, due to busy cpu. In the Alpine chip family an option to change the default behavior was added to the original dw spi controller to prevent this issue of de-asserting Chip-Select once TX FIFO is empty. The change was to allow SW manual control of the Chip-Select. With this change, as long as the Slave Enable Register is asserted, the Chip-Select will be asserted. As a result, it is necessary to deselect the Slave Select Register once the transaction is done. This feature is enabled via a new device compatible string called 'amazon,alpine-dw-apb-ssi'. Once the driver identifies the new compatible string, it enables the hw fixup logic, by writing to a dedicated register found in the IP reserved area and will start manual deselecting the Slave Select Register when the transfer ends. Signed-off-by: Talel Shenhar Signed-off-by: David Woodhouse --- Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt index 642d3fb..2864bc6 100644 --- a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt +++ b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt @@ -2,7 +2,7 @@ Synopsys DesignWare AMBA 2.0 Synchronous Serial Interface. Required properties: - compatible : "snps,dw-apb-ssi" or "mscc,-spi", where soc is "ocelot" or - "jaguar2" + "jaguar2", or "amazon,alpine-dw-apb-ssi" - reg : The register base for the controller. For "mscc,-spi", a second register set is required (named ICPU_CFG:SPI_MST) - interrupts : One interrupt, used by the controller.