From patchwork Tue Apr 22 16:45:48 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 341406 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 08622140121 for ; Wed, 23 Apr 2014 02:46:29 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932782AbaDVQqZ (ORCPT ); Tue, 22 Apr 2014 12:46:25 -0400 Received: from mail-ie0-f201.google.com ([209.85.223.201]:44311 "EHLO mail-ie0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932643AbaDVQqV (ORCPT ); Tue, 22 Apr 2014 12:46:21 -0400 Received: by mail-ie0-f201.google.com with SMTP id rd18so1215223iec.2 for ; Tue, 22 Apr 2014 09:46:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=gVukRlmLh6xJmj/Ny/ZAcBnkgJLwCEqBJmH33qF3PPs=; b=krbvu+GeuIgHrw7bBHfZW6QXrZvsHRbzgYbGxTyMUOcjn9Uaah6dWeeHWB327ciCFG MfvgG8GZJBMYgQjLHJBmFLbpCzIPLA8o7+PdlVHFv4+tIGQeaYtKfnFBi0cuVhrA+S7B FDDHrls6Njs18uKL4TgN6a6wptwsBY/ogLtWRvRHVjHMbkmvFHDDproPy1BypLrO25oA hzef//CtGa3APvq9RbyPzW1xpVlMmNEB8ZEbBZgvzgbneHDxzdCC1MwwRGrV3fFR/7yE jR3U6WuBUBcUX19AbmKJgkH2f4mMljfK8LkZ2AyowBVe8BdvoFRlCiJreu4omEB3RD9x 7cjg== X-Gm-Message-State: ALoCoQnVGmg3jo/wCns1oUNwhrOFkBHABjqAyKRSgnvSr0+DoPThJnJDiRGYTMVdvpXxvRTuGzyUXR+CBBDmXjBLFPTUh8WZqrPKbB1dVhszXMKF/woS/tPqHPgIexZnodHdGPkkPJLupfmpPYhtJMpuH8Affk0cP822fiCqqh4xrXQvtHjUQvvoad2LDhx6gVZ9g6Bukc+Y9POR0rPARXwGBRIrmcwG2Q== X-Received: by 10.42.62.11 with SMTP id w11mr18535283ich.29.1398185180729; Tue, 22 Apr 2014 09:46:20 -0700 (PDT) Received: from corp2gmr1-2.hot.corp.google.com (corp2gmr1-2.hot.corp.google.com [172.24.189.93]) by gmr-mx.google.com with ESMTPS id s65si5666430yhc.2.2014.04.22.09.46.20 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 22 Apr 2014 09:46:20 -0700 (PDT) Received: from tictac.mtv.corp.google.com (tictac.mtv.corp.google.com [172.22.72.141]) by corp2gmr1-2.hot.corp.google.com (Postfix) with ESMTP id 889F55A4298; Tue, 22 Apr 2014 09:46:20 -0700 (PDT) Received: by tictac.mtv.corp.google.com (Postfix, from userid 121310) id 2AEB280535; Tue, 22 Apr 2014 09:46:20 -0700 (PDT) From: Doug Anderson To: lee.jones@linaro.org, swarren@nvidia.com, wsa@the-dreams.de Cc: abrestic@chromium.org, dgreid@chromium.org, olof@lixom.net, sjg@chromium.org, linux-samsung-soc@vger.kernel.org, linux-tegra@vger.kernel.org, David Hendricks , Doug Anderson , sameo@linux.intel.com, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/7] mfd: cros_ec: spi: calculate delay between transfers correctly Date: Tue, 22 Apr 2014 09:45:48 -0700 Message-Id: <1398185154-19404-2-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 1.9.1.423.g4596e3a In-Reply-To: <1398185154-19404-1-git-send-email-dianders@chromium.org> References: <1398185154-19404-1-git-send-email-dianders@chromium.org> Sender: linux-tegra-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org From: David Hendricks To avoid spamming the EC we calculate the time between the previous transfer and the current transfer and force a delay if the time delta is too small. However, a small miscalculation causes the delay period to be far too short. Most noticably this impacts commands with a long turnaround time such as EC firmware reads and writes. Signed-off-by: David Hendricks Signed-off-by: Doug Anderson Reviewed-by: Simon Glass Tested-by: Andrew Bresticker Tested-by: Stephen Warren --- Changes in v2: None drivers/mfd/cros_ec_spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index 84af8d7..c185eb6 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -219,7 +219,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, ktime_get_ts(&ts); delay = timespec_to_ns(&ts) - ec_spi->last_transfer_ns; if (delay < EC_SPI_RECOVERY_TIME_NS) - ndelay(delay); + ndelay(EC_SPI_RECOVERY_TIME_NS - delay); } /* Transmit phase - send our message */