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[75.70.96.103]) by smtp.gmail.com with ESMTPSA id r9sm793469iom.44.2019.01.14.16.15.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 14 Jan 2019 16:15:45 -0800 (PST) Date: Mon, 14 Jan 2019 17:15:39 -0700 From: Jeremy Fertic To: Tomasz Duszynski Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] iio: chemical: sps30: allow changing self cleaning period Message-ID: <20190115001539.GA20418@r2700x.localdomain> References: <20190113100912.29665-1-tduszyns@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190113100912.29665-1-tduszyns@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 13, 2019 at 11:09:12AM +0100, Tomasz Duszynski wrote: > Sensor can periodically trigger self cleaning. Period can be changed by > writing a new value to a dedicated attribute. Upon attribute read > current period gets returned. > > Signed-off-by: Tomasz Duszynski > --- > v3: > * add info about used units to attribute docs > > v2: > * return available values formated as a range > * tweak naming a little (interval -> period) > > Documentation/ABI/testing/sysfs-bus-iio-sps30 | 20 +++ > drivers/iio/chemical/sps30.c | 143 +++++++++++++++--- > 2 files changed, 145 insertions(+), 18 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-sps30 b/Documentation/ABI/testing/sysfs-bus-iio-sps30 > index e7ce2c57635e..143df8e89d08 100644 > --- a/Documentation/ABI/testing/sysfs-bus-iio-sps30 > +++ b/Documentation/ABI/testing/sysfs-bus-iio-sps30 > @@ -6,3 +6,23 @@ Description: > Writing 1 starts sensor self cleaning. Internal fan accelerates > to its maximum speed and keeps spinning for about 10 seconds in > order to blow out accumulated dust. > + > +What: /sys/bus/iio/devices/iio:deviceX/cleaning_period > +Date: January 2019 > +KernelVersion: 5.1 > +Contact: linux-iio@vger.kernel.org > +Description: > + Sensor is capable of triggering self cleaning periodically. > + Period can be changed by writing a new value here. Upon reading > + the current one is returned. Units are seconds. > + > + Writing 0 disables periodical self cleaning entirely. > + > +What: /sys/bus/iio/devices/iio:deviceX/cleaning_period_available > +Date: January 2019 > +KernelVersion: 5.1 > +Contact: linux-iio@vger.kernel.org > +Description: > + The range of available values in seconds represented as the > + minimum value, the step and the maximum value, all enclosed in > + square brackets. > diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c > index f3b4390c8f5c..fe5f6309191b 100644 > --- a/drivers/iio/chemical/sps30.c > +++ b/drivers/iio/chemical/sps30.c > @@ -5,9 +5,6 @@ > * Copyright (c) Tomasz Duszynski > * > * I2C slave address: 0x69 > - * > - * TODO: > - * - support for reading/setting auto cleaning interval > */ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > @@ -21,6 +18,7 @@ > #include > #include > #include > +#include > #include > > #define SPS30_CRC8_POLYNOMIAL 0x31 > @@ -28,6 +26,9 @@ > #define SPS30_MAX_READ_SIZE 48 > /* sensor measures reliably up to 3000 ug / m3 */ > #define SPS30_MAX_PM 3000 > +/* minimum and maximum self cleaning periods in seconds */ > +#define SPS30_AUTO_CLEANING_PERIOD_MIN 0 > +#define SPS30_AUTO_CLEANING_PERIOD_MAX 604800 > > /* SPS30 commands */ > #define SPS30_START_MEAS 0x0010 > @@ -37,6 +38,9 @@ > #define SPS30_READ_DATA 0x0300 > #define SPS30_READ_SERIAL 0xd033 > #define SPS30_START_FAN_CLEANING 0x5607 > +#define SPS30_AUTO_CLEANING_PERIOD 0x8004 > +/* not a sensor command per se, used only to distinguish write from read */ > +#define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005 > > enum { > PM1, > @@ -45,6 +49,11 @@ enum { > PM10, > }; > > +enum { > + RESET, > + MEASURING, > +}; > + > struct sps30_state { > struct i2c_client *client; > /* > @@ -52,6 +61,7 @@ struct sps30_state { > * Must be held whenever sequence of commands is to be executed. > */ > struct mutex lock; > + int state; > }; > > DECLARE_CRC8_TABLE(sps30_crc8_table); > @@ -107,6 +117,9 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size) > case SPS30_START_FAN_CLEANING: > ret = sps30_write_then_read(state, buf, 2, NULL, 0); > break; > + case SPS30_READ_AUTO_CLEANING_PERIOD: > + buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8; > + buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD; > case SPS30_READ_DATA_READY_FLAG: > case SPS30_READ_DATA: > case SPS30_READ_SERIAL: > @@ -114,6 +127,15 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size) > size += size / 2; > ret = sps30_write_then_read(state, buf, 2, buf, size); > break; > + case SPS30_AUTO_CLEANING_PERIOD: > + buf[2] = data[0]; > + buf[3] = data[1]; > + buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE); > + buf[5] = data[2]; > + buf[6] = data[3]; > + buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE); > + ret = sps30_write_then_read(state, buf, 8, NULL, 0); > + break; > } > > if (ret) > @@ -170,6 +192,14 @@ static int sps30_do_meas(struct sps30_state *state, s32 *data, int size) > int i, ret, tries = 5; > u8 tmp[16]; > > + if (state->state == RESET) { > + ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0); > + if (ret) > + return ret; > + > + state->state = MEASURING; > + } > + > while (tries--) { > ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2); > if (ret) > @@ -276,6 +306,24 @@ static int sps30_read_raw(struct iio_dev *indio_dev, > return -EINVAL; > } > > +static int sps30_do_cmd_reset(struct sps30_state *state) > +{ > + int ret; > + > + ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0); > + msleep(300); > + /* > + * Power-on-reset causes sensor to produce some glitch on i2c bus and > + * some controllers end up in error state. Recover simply by placing > + * some data on the bus, for example STOP_MEAS command, which > + * is NOP in this case. > + */ > + sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); > + state->state = RESET; > + > + return ret; > +} > + > static ssize_t start_cleaning_store(struct device *dev, > struct device_attribute *attr, > const char *buf, size_t len) > @@ -296,10 +344,82 @@ static ssize_t start_cleaning_store(struct device *dev, > return len; > } > > +static ssize_t cleaning_period_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > + struct sps30_state *state = iio_priv(indio_dev); > + u8 tmp[4]; > + int ret; > + > + mutex_lock(&state->lock); > + ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4); > + mutex_unlock(&state->lock); > + if (ret) > + return ret; > + > + return sprintf(buf, "%d\n", get_unaligned_be32(tmp)); > +} > + > +static ssize_t cleaning_period_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + struct iio_dev *indio_dev = dev_to_iio_dev(dev); > + struct sps30_state *state = iio_priv(indio_dev); > + int val, ret; > + u8 tmp[4]; > + > + if (kstrtoint(buf, 0, &val)) > + return -EINVAL; > + > + if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) && > + (val > SPS30_AUTO_CLEANING_PERIOD_MAX)) > + return -EINVAL; Should this be || instead of &&? Jeremy > + > + put_unaligned_be32(val, tmp); > + > + mutex_lock(&state->lock); > + ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0); > + if (ret) { > + mutex_unlock(&state->lock); > + return ret; > + } > + > + msleep(20); > + > + /* > + * sensor requires reset in order to return up to date self cleaning > + * period > + */ > + ret = sps30_do_cmd_reset(state); > + if (ret) > + dev_warn(dev, > + "period changed but reads will return the old value\n"); > + > + mutex_unlock(&state->lock); > + > + return len; > +} > + > +static ssize_t cleaning_period_available_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n", > + SPS30_AUTO_CLEANING_PERIOD_MIN, 1, > + SPS30_AUTO_CLEANING_PERIOD_MAX); > +} > + > static IIO_DEVICE_ATTR_WO(start_cleaning, 0); > +static IIO_DEVICE_ATTR_RW(cleaning_period, 0); > +static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0); > > static struct attribute *sps30_attrs[] = { > &iio_dev_attr_start_cleaning.dev_attr.attr, > + &iio_dev_attr_cleaning_period.dev_attr.attr, > + &iio_dev_attr_cleaning_period_available.dev_attr.attr, > NULL > }; > > @@ -362,6 +482,7 @@ static int sps30_probe(struct i2c_client *client) > state = iio_priv(indio_dev); > i2c_set_clientdata(client, indio_dev); > state->client = client; > + state->state = RESET; > indio_dev->dev.parent = &client->dev; > indio_dev->info = &sps30_info; > indio_dev->name = client->name; > @@ -373,19 +494,11 @@ static int sps30_probe(struct i2c_client *client) > mutex_init(&state->lock); > crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL); > > - ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0); > + ret = sps30_do_cmd_reset(state); > if (ret) { > dev_err(&client->dev, "failed to reset device\n"); > return ret; > } > - msleep(300); > - /* > - * Power-on-reset causes sensor to produce some glitch on i2c bus and > - * some controllers end up in error state. Recover simply by placing > - * some data on the bus, for example STOP_MEAS command, which > - * is NOP in this case. > - */ > - sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); > > ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf)); > if (ret) { > @@ -395,12 +508,6 @@ static int sps30_probe(struct i2c_client *client) > /* returned serial number is already NUL terminated */ > dev_info(&client->dev, "serial number: %s\n", buf); > > - ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0); > - if (ret) { > - dev_err(&client->dev, "failed to start measurement\n"); > - return ret; > - } > - > ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state); > if (ret) > return ret; > -- > 2.20.1 >