Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751590AbdISGRM (ORCPT ); Tue, 19 Sep 2017 02:17:12 -0400 Received: from ns.pmeerw.net ([84.19.176.117]:46510 "EHLO vps.pmeerw.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751465AbdISGRK (ORCPT ); Tue, 19 Sep 2017 02:17:10 -0400 Date: Tue, 19 Sep 2017 08:17:08 +0200 (CEST) From: Peter Meerwald-Stadler To: =?ISO-8859-15?Q?Stefan_Br=FCns?= cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen Subject: Re: [PATCH 3/4] iio: light: vl6180: Cleanup als_gain lookup, avoid register readback In-Reply-To: <20170919031144.4968-4-stefan.bruens@rwth-aachen.de> Message-ID: References: <20170919031144.4968-1-stefan.bruens@rwth-aachen.de> <20170919031144.4968-4-stefan.bruens@rwth-aachen.de> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="324302256-1813071391-1505801828=:8589" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5034 Lines: 170 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --324302256-1813071391-1505801828=:8589 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT > Instead of manually iterating the array of allowed gain values, use > find_closest. Storing the current gain setting avoids accessing the > hardware on each query. nitpick below > Signed-off-by: Stefan Brüns > --- > drivers/iio/light/vl6180.c | 85 ++++++++++++++++++++++++---------------------- > 1 file changed, 44 insertions(+), 41 deletions(-) > > diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c > index ae768c832d66..fcd8ef511bdc 100644 > --- a/drivers/iio/light/vl6180.c > +++ b/drivers/iio/light/vl6180.c > @@ -24,6 +24,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -86,6 +87,7 @@ > struct vl6180_data { > struct i2c_client *client; > struct mutex lock; > + unsigned int als_gain_milli; > unsigned int als_it_ms; > }; > > @@ -276,19 +278,17 @@ static const struct iio_chan_spec vl6180_channels[] = { > }; > > /* > - * Columns 3 & 4 represent the same value in decimal and hex notations. > - * Kept in order to avoid the datatype conversion while reading the > - * hardware_gain. > + * Available Ambient Light Sensor gain settings, 1/1000th, and > + * corresponding setting for the VL6180_ALS_GAIN register > */ > -static const int vl6180_als_gain[8][4] = { > - { 1, 0, 70, VL6180_ALS_GAIN_1 }, > - { 1, 250000, 69, VL6180_ALS_GAIN_1_25 }, > - { 1, 670000, 68, VL6180_ALS_GAIN_1_67 }, > - { 2, 500000, 67, VL6180_ALS_GAIN_2_5 }, > - { 5, 0, 66, VL6180_ALS_GAIN_5 }, > - { 10, 0, 65, VL6180_ALS_GAIN_10 }, > - { 20, 0, 64, VL6180_ALS_GAIN_20 }, > - { 40, 0, 71, VL6180_ALS_GAIN_40 } > +static const int vl6180_als_gain_tab[8] = { > + 1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000 > +}; > +static const u8 vl6180_als_gain_tab_bits[8] = { > + VL6180_ALS_GAIN_1, VL6180_ALS_GAIN_1_25, > + VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5, > + VL6180_ALS_GAIN_5, VL6180_ALS_GAIN_10, > + VL6180_ALS_GAIN_20, VL6180_ALS_GAIN_40 > }; > > static int vl6180_read_raw(struct iio_dev *indio_dev, > @@ -296,7 +296,7 @@ static int vl6180_read_raw(struct iio_dev *indio_dev, > int *val, int *val2, long mask) > { > struct vl6180_data *data = iio_priv(indio_dev); > - int ret, i; > + int ret; > > switch (mask) { > case IIO_CHAN_INFO_RAW: > @@ -328,17 +328,11 @@ static int vl6180_read_raw(struct iio_dev *indio_dev, > > return IIO_VAL_INT_PLUS_MICRO; > case IIO_CHAN_INFO_HARDWAREGAIN: > - ret = vl6180_read_byte(data->client, VL6180_ALS_GAIN); > - if (ret < 0) > - return -EINVAL; > - for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) { > - if (ret == vl6180_als_gain[i][2]) { > - *val = vl6180_als_gain[i][0]; > - *val2 = vl6180_als_gain[i][1]; > - } > - } > + *val = data->als_gain_milli; > + *val2 = 1000; > + > + return IIO_VAL_FRACTIONAL; > > - return IIO_VAL_INT_PLUS_MICRO; > default: > return -EINVAL; > } > @@ -364,25 +358,33 @@ static int vl6180_hold(struct vl6180_data *data, bool hold) > > static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2) > { > - int i, ret; > - > - for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) { > - if (val == vl6180_als_gain[i][0] && > - val2 == vl6180_als_gain[i][1]) { > - mutex_lock(&data->lock); > - ret = vl6180_hold(data, true); > - if (ret < 0) > - goto fail; > - ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN, > - vl6180_als_gain[i][3]); > -fail: > - vl6180_hold(data, false); > - mutex_unlock(&data->lock); > - return ret; > - } > - } > + int i, ret, gain; > + > + if (val < 1 || val > 40) > + return -EINVAL; > + > + gain = (val * 1000000 + val2)/1000; spaces around / operator > + if (gain < 1 || gain > 40000) > + return -EINVAL; > + > + i = find_closest(gain, vl6180_als_gain_tab, > + ARRAY_SIZE(vl6180_als_gain_tab)); > + > + mutex_lock(&data->lock); > + ret = vl6180_hold(data, true); > + if (ret < 0) > + goto fail; > > - return -EINVAL; > + ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN, > + vl6180_als_gain_tab_bits[i]); > + > + if (ret >= 0) > + data->als_gain_milli = vl6180_als_gain_tab[i]; > + > +fail: > + vl6180_hold(data, false); > + mutex_unlock(&data->lock); > + return ret; > } > > static int vl6180_set_it(struct vl6180_data *data, int val, int val2) > @@ -480,6 +482,7 @@ static int vl6180_init(struct vl6180_data *data) > return ret; > > /* ALS gain: 1 */ > + data->als_gain_milli = 1000; > ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1); > if (ret < 0) > return ret; > -- Peter Meerwald-Stadler Mobile: +43 664 24 44 418 --324302256-1813071391-1505801828=:8589--