From patchwork Tue Aug 4 14:04:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Irina Tirdea X-Patchwork-Id: 503612 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 C1BD5140306 for ; Wed, 5 Aug 2015 00:06:17 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934296AbbHDOF6 (ORCPT ); Tue, 4 Aug 2015 10:05:58 -0400 Received: from mga11.intel.com ([192.55.52.93]:24864 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934352AbbHDOFN (ORCPT ); Tue, 4 Aug 2015 10:05:13 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP; 04 Aug 2015 07:05:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,609,1432623600"; d="scan'208";a="619049459" Received: from trudden-mobl.ger.corp.intel.com (HELO itirdea-mobl4.ger.corp.intel.com) ([10.252.3.67]) by orsmga003.jf.intel.com with ESMTP; 04 Aug 2015 07:05:09 -0700 From: Irina Tirdea To: Wolfram Sang , Jonathan Cameron , linux-iio@vger.kernel.org, linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Srinivas Pandruvada , Peter Meerwald , Adriana Reus , Irina Tirdea Subject: [PATCH v4 8/8] iio: accel: kxcjk-1013: optimize i2c transfers in trigger handler Date: Tue, 4 Aug 2015 17:04:16 +0300 Message-Id: <1438697056-2946-9-git-send-email-irina.tirdea@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438697056-2946-1-git-send-email-irina.tirdea@intel.com> References: <1438697056-2946-1-git-send-email-irina.tirdea@intel.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Adriana Reus Some i2c busses (e.g.: Synopsys DesignWare I2C adapter) need to enable/disable the bus at each i2c transfer and must wait for the enable/disable to happen before sending the data. When reading data in the trigger handler, the kxcjk-1013 accel driver does one i2c transfer for each axis. This has an impact on the frequency of the accelerometer at high sample rates due to additional delays introduced by the i2c bus at each transfer. Reading all axis values in one i2c transfer reduces the delays introduced by the i2c bus. Uses i2c_smbus_read_i2c_block_data_or_emulated that will fallback to reading each axis as a separate word in case i2c block read is not supported. Signed-off-by: Adriana Reus Signed-off-by: Irina Tirdea Acked-by: Jonathan Cameron Acked-by: Srinivas Pandruvada --- drivers/iio/accel/kxcjk-1013.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c index d4b80e7..e8f7b45 100644 --- a/drivers/iio/accel/kxcjk-1013.c +++ b/drivers/iio/accel/kxcjk-1013.c @@ -926,7 +926,7 @@ static const struct iio_event_spec kxcjk1013_event = { .realbits = 12, \ .storagebits = 16, \ .shift = 4, \ - .endianness = IIO_CPU, \ + .endianness = IIO_LE, \ }, \ .event_spec = &kxcjk1013_event, \ .num_event_specs = 1 \ @@ -964,19 +964,16 @@ static irqreturn_t kxcjk1013_trigger_handler(int irq, void *p) struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct kxcjk1013_data *data = iio_priv(indio_dev); - int bit, ret, i = 0; + int ret; mutex_lock(&data->mutex); - - for (bit = 0; bit < AXIS_MAX; bit++) { - ret = kxcjk1013_get_acc_reg(data, bit); - if (ret < 0) { - mutex_unlock(&data->mutex); - goto err; - } - data->buffer[i++] = ret; - } + ret = i2c_smbus_read_i2c_block_data_or_emulated(data->client, + KXCJK1013_REG_XOUT_L, + AXIS_MAX * 2, + (u8 *)data->buffer); mutex_unlock(&data->mutex); + if (ret < 0) + goto err; iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, data->timestamp);