Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753341AbbFDIKf (ORCPT ); Thu, 4 Jun 2015 04:10:35 -0400 Received: from bhuna.collabora.co.uk ([93.93.135.160]:43414 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752780AbbFDIG4 (ORCPT ); Thu, 4 Jun 2015 04:06:56 -0400 From: Javier Martinez Canillas To: Lee Jones Cc: Samuel Ortiz , Olof Johansson , Doug Anderson , Bill Richardson , Simon Glass , Gwendal Grignou , Stephen Barber , Filipe Brandenburger , Todd Broch , Alexandru M Stan , Heiko Stuebner , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Chris Zhong , Javier Martinez Canillas Subject: [PATCH v6 7/8] mfd: cros_ec: spi: Add a DT property to delay asserting the CS Date: Thu, 4 Jun 2015 10:05:53 +0200 Message-Id: <1433405154-16273-8-git-send-email-javier.martinez@collabora.co.uk> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1433405154-16273-1-git-send-email-javier.martinez@collabora.co.uk> References: <1433405154-16273-1-git-send-email-javier.martinez@collabora.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2232 Lines: 57 From: Alexandru M Stan Some ECs need a little time for waking up before they can accept SPI data at a high speed. Add a "google,cros-ec-spi-pre-delay" property to the DT binding to configure this. If this property isn't set, then no delay will be added. However, if set it will cause a delay equal to the value passed to it to be inserted at the beginning of a transaction. Signed-off-by: Alexandru M Stan Reviewed-by: Doug Anderson Signed-off-by: Chris Zhong Signed-off-by: Javier Martinez Canillas Tested-by: Heiko Stuebner Acked-by: Lee Jones --- Changes since v5: None. Changes since v4: None. Changes since v3: - Split DT binding and driver change as suggested by Lee Jones. - Add tested-by tag from Heiko Stuebner - Add acked-by tag from Lee Jones. Changes since v2: None Changes since v1: None, new patch --- Documentation/devicetree/bindings/mfd/cros-ec.txt | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/devicetree/bindings/mfd/cros-ec.txt b/Documentation/devicetree/bindings/mfd/cros-ec.txt index 8009c3d87f33..1777916e9e28 100644 --- a/Documentation/devicetree/bindings/mfd/cros-ec.txt +++ b/Documentation/devicetree/bindings/mfd/cros-ec.txt @@ -18,6 +18,10 @@ Required properties (SPI): - reg: SPI chip select Optional properties (SPI): +- google,cros-ec-spi-pre-delay: Some implementations of the EC need a little + time to wake up from sleep before they can receive SPI transfers at a high + clock rate. This property specifies the delay, in usecs, between the + assertion of the CS to the start of the first clock pulse. - google,cros-ec-spi-msg-delay: Some implementations of the EC require some additional processing time in order to accept new transactions. If the delay between transactions is not long enough the EC may not be able to respond -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/