Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757131AbcCXJaA (ORCPT ); Thu, 24 Mar 2016 05:30:00 -0400 Received: from mga14.intel.com ([192.55.52.115]:19827 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757020AbcCXJ3s (ORCPT ); Thu, 24 Mar 2016 05:29:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,384,1455004800"; d="scan'208";a="72381432" From: Irina Tirdea To: Jonathan Cameron , linux-iio@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald , Octavian Purdila , Markus Pargmann , Srinivas Pandruvada , Irina Tirdea Subject: [PATCH 2/6] iio: accel: bmc150: optimize transfers in trigger handler Date: Thu, 24 Mar 2016 11:29:27 +0200 Message-Id: <1458811771-25217-3-git-send-email-irina.tirdea@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1458811771-25217-1-git-send-email-irina.tirdea@intel.com> References: <1458811771-25217-1-git-send-email-irina.tirdea@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2015 Lines: 58 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 bmc150 accel driver does one bus 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 bus at each transfer. Reading all axis values in one bus transfer reduces the delays introduced by the bus. Signed-off-by: Irina Tirdea --- drivers/iio/accel/bmc150-accel-core.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/drivers/iio/accel/bmc150-accel-core.c b/drivers/iio/accel/bmc150-accel-core.c index cc52366..58df97d 100644 --- a/drivers/iio/accel/bmc150-accel-core.c +++ b/drivers/iio/accel/bmc150-accel-core.c @@ -989,6 +989,7 @@ static const struct iio_event_spec bmc150_accel_event = { .realbits = (bits), \ .storagebits = 16, \ .shift = 16 - (bits), \ + .endianness = IIO_LE, \ }, \ .event_spec = &bmc150_accel_event, \ .num_event_specs = 1 \ @@ -1114,21 +1115,14 @@ static irqreturn_t bmc150_accel_trigger_handler(int irq, void *p) struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct bmc150_accel_data *data = iio_priv(indio_dev); - int bit, ret, i = 0; - unsigned int raw_val; + int ret; mutex_lock(&data->mutex); - for (bit = 0; bit < AXIS_MAX; bit++) { - ret = regmap_bulk_read(data->regmap, - BMC150_ACCEL_AXIS_TO_REG(bit), &raw_val, - 2); - if (ret < 0) { - mutex_unlock(&data->mutex); - goto err_read; - } - data->buffer[i++] = raw_val; - } + ret = regmap_bulk_read(data->regmap, BMC150_ACCEL_REG_XOUT_L, + data->buffer, AXIS_MAX * 2); mutex_unlock(&data->mutex); + if (ret < 0) + goto err_read; iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, pf->timestamp); -- 1.9.1