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Wed, 27 May 2026 11:43:05 -0700 (PDT) From: Wadim Mueller To: Jonathan Cameron , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko , Maxwell Doose , linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org Cc: Guenter Roeck , Jean Delvare , Andreas Klinger , Lars-Peter Clausen , linux-hwmon@vger.kernel.org Subject: [PATCH v2 3/3] iio: flow: add Sensirion SLF3S liquid flow sensor driver Date: Wed, 27 May 2026 20:42:54 +0200 Message-ID: <20260527184257.141635-4-wafgo01@gmail.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260527184257.141635-1-wafgo01@gmail.com> References: <20260524205112.26638-1-wafgo01@gmail.com> <20260527184257.141635-1-wafgo01@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a driver for the Sensirion SLF3S family of digital liquid-flow sensors (SLF3S-0600F, SLF3S-1300F and SLF3S-4000B). The sensors communicate over I2C and return a 16-bit signed flow value, a 16-bit signed temperature reading and a status word - each protected by a CRC-8 byte - in every measurement frame. The driver exposes: in_volumeflow_raw - signed raw counts in_volumeflow_scale - litres per second per LSB (per variant) in_temp_raw - signed raw counts in_temp_scale - millidegrees Celsius per LSB The variant is auto-detected from the product-info word read at probe time. All three SLF3S devices are factory-calibrated for both water and isopropyl alcohol; the calibration medium is selected via the sensirion,medium device property and defaults to water. Scale factors are taken from the respective datasheets (Table 16 for SLF3S-0600F, Table 15 for SLF3S-1300F and SLF3S-4000B): SLF3S-0600F: 10 (ul/min)^-1 -> 1/600 000 000 (l/s)/LSB SLF3S-1300F: 500 (ml/min)^-1 -> 1/30 000 000 (l/s)/LSB SLF3S-4000B: 32 (ml/min)^-1 -> 1/1 920 000 (l/s)/LSB Signed-off-by: Wadim Mueller Cc: Guenter Roeck Cc: Jean Delvare Cc: Andreas Klinger Cc: Lars-Peter Clausen Cc: linux-hwmon@vger.kernel.org Cc: Maxwell Doose --- drivers/iio/Kconfig | 1 + drivers/iio/Makefile | 1 + drivers/iio/flow/Kconfig | 27 +++ drivers/iio/flow/Makefile | 7 + drivers/iio/flow/slf3s.c | 345 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 381 insertions(+) create mode 100644 drivers/iio/flow/Kconfig create mode 100644 drivers/iio/flow/Makefile create mode 100644 drivers/iio/flow/slf3s.c diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig index 661127aed..652557a5b 100644 --- a/drivers/iio/Kconfig +++ b/drivers/iio/Kconfig @@ -92,6 +92,7 @@ source "drivers/iio/common/Kconfig" source "drivers/iio/dac/Kconfig" source "drivers/iio/dummy/Kconfig" source "drivers/iio/filter/Kconfig" +source "drivers/iio/flow/Kconfig" source "drivers/iio/frequency/Kconfig" source "drivers/iio/gyro/Kconfig" source "drivers/iio/health/Kconfig" diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile index cb80ef837..f03a4100c 100644 --- a/drivers/iio/Makefile +++ b/drivers/iio/Makefile @@ -29,6 +29,7 @@ obj-y += dac/ obj-y += dummy/ obj-y += gyro/ obj-y += filter/ +obj-y += flow/ obj-y += frequency/ obj-y += health/ obj-y += humidity/ diff --git a/drivers/iio/flow/Kconfig b/drivers/iio/flow/Kconfig new file mode 100644 index 000000000..1eee131ea --- /dev/null +++ b/drivers/iio/flow/Kconfig @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Liquid / gas flow sensor drivers +# +# When adding new entries keep the list in alphabetical order + +menu "Flow sensors" + +config SENSIRION_SLF3S + tristate "Sensirion SLF3S liquid flow sensor" + depends on I2C + select CRC8 + help + Say yes here to build support for the Sensirion SLF3S family + of digital liquid-flow sensors: + + - SLF3S-0600F + - SLF3S-1300F + - SLF3S-4000B + + The driver reports the volumetric flow rate and the embedded + temperature reading via the standard IIO interface. + + To compile this driver as a module, choose M here: the module + will be called slf3s. + +endmenu diff --git a/drivers/iio/flow/Makefile b/drivers/iio/flow/Makefile new file mode 100644 index 000000000..3cf4ab95c --- /dev/null +++ b/drivers/iio/flow/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for industrial I/O flow sensor drivers +# + +# When adding new entries keep the list in alphabetical order +obj-$(CONFIG_SENSIRION_SLF3S) += slf3s.o diff --git a/drivers/iio/flow/slf3s.c b/drivers/iio/flow/slf3s.c new file mode 100644 index 000000000..f971a2dc2 --- /dev/null +++ b/drivers/iio/flow/slf3s.c @@ -0,0 +1,345 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sensirion SLF3S liquid flow sensor driver. + * + * Supports the SLF3S-0600F, SLF3S-1300F and SLF3S-4000B liquid-flow + * sensors over I2C. Each measurement frame returns a 16-bit signed + * flow value, a 16-bit signed temperature value and a status word, + * each protected by a CRC-8 byte. + * + * Datasheet: https://sensirion.com/products/catalog/SLF3S-0600F/ + * + * Copyright (C) 2026 CMBlu Energy GmbH + * Author: Wadim Mueller + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define SLF3S_CRC8_POLY 0x31 +#define SLF3S_CRC8_INIT 0xff + +#define SLF3S_PRODUCT_ID_LEN 18 +#define SLF3S_PRODUCT_FAMILY_BYTE 1 +#define SLF3S_PRODUCT_SUBTYPE_BYTE 3 +#define SLF3S_PRODUCT_FAMILY_ID 0x03 + +#define SLF3S_MEAS_LEN 9 +#define SLF3S_MEAS_START_DELAY_US 12000 + +/* + * Temperature LSB equals 1/200 degC. IIO_TEMP uses milli-degrees, + * therefore the scale exposed to userspace is 1000 / 200 = 5. + */ +#define SLF3S_TEMP_SCALE_MILLIC 5 + +static const u8 slf3s_cmd_prep_pid[] = { 0x36, 0x7c }; +static const u8 slf3s_cmd_read_pid[] = { 0xe1, 0x02 }; +static const u8 slf3s_cmd_start_water[] = { 0x36, 0x08 }; +static const u8 slf3s_cmd_start_ipa[] = { 0x36, 0x15 }; +static const u8 slf3s_cmd_stop_meas[] = { 0x3f, 0xf9 }; + +/** + * struct slf3s_variant - per-variant calibration constants + * @sub_type: product-info sub-type byte returned by the sensor + * @name: name reported via @iio_dev.name + * @scale_num: flow scale numerator (l/s per LSB) + * @scale_den: flow scale denominator (l/s per LSB) + */ +struct slf3s_variant { + u8 sub_type; + const char *name; + int scale_num; + int scale_den; +}; + +static const struct slf3s_variant slf3s_variants[] = { + [0] = { + .sub_type = 0x03, + .name = "slf3s-0600f", + .scale_num = 1, + .scale_den = 600000000, + }, + [1] = { + .sub_type = 0x02, + .name = "slf3s-1300f", + .scale_num = 1, + .scale_den = 30000000, + }, + [2] = { + .sub_type = 0x05, + .name = "slf3s-4000b", + .scale_num = 1, + .scale_den = 1920000, + }, +}; + +/** + * struct slf3s_data - per-device state + * @client: I2C client this instance is bound to + * @variant: pointer into @slf3s_variants for the detected device + * @crc_table: pre-computed CRC-8 lookup table for SLF3S_CRC8_POLY + */ +struct slf3s_data { + struct i2c_client *client; + const struct slf3s_variant *variant; + u8 crc_table[CRC8_TABLE_SIZE]; +}; + +static bool slf3s_crc_valid(const struct slf3s_data *sf, const u8 *block) +{ + return crc8(sf->crc_table, block, 2, SLF3S_CRC8_INIT) == block[2]; +} + +static int slf3s_send_cmd(struct i2c_client *client, const u8 cmd[static 2]) +{ + int ret = i2c_master_send(client, cmd, 2); + + if (ret == 2) + return 0; + return ret < 0 ? ret : -EIO; +} + +/* + * Read the product-info block and update @sf->variant. The kernel + * trusts the DT compatible (or i2c id_table .data) above all else; the + * sub-type byte is a sanity hint. This means: + * + * - bus / CRC failures are real errors and must fail probe; + * - if the caller already picked a variant (specific compatible), the + * PID is logged for diagnostics but mismatches do not fail probe; + * - if the caller has no variant (generic "sensirion,slf3s" fallback), + * the sub-type byte is used to pick one; unknown sub-type fails. + */ +static int slf3s_detect_variant(struct slf3s_data *sf) +{ + struct i2c_client *client = sf->client; + u8 buf[SLF3S_PRODUCT_ID_LEN]; + int ret; + + ret = slf3s_send_cmd(client, slf3s_cmd_prep_pid); + if (ret) + return ret; + + ret = slf3s_send_cmd(client, slf3s_cmd_read_pid); + if (ret) + return ret; + + ret = i2c_master_recv(client, buf, sizeof(buf)); + if (ret < 0) + return ret; + if (ret != sizeof(buf)) + return -EIO; + + for (unsigned int i = 0; i < SLF3S_PRODUCT_ID_LEN; i += 3) { + if (!slf3s_crc_valid(sf, &buf[i])) + return -EIO; + } + + if (buf[SLF3S_PRODUCT_FAMILY_BYTE] != SLF3S_PRODUCT_FAMILY_ID) + dev_dbg(&client->dev, + "unexpected family byte 0x%02x (expected 0x%02x)\n", + buf[SLF3S_PRODUCT_FAMILY_BYTE], + SLF3S_PRODUCT_FAMILY_ID); + + for (unsigned int i = 0; i < ARRAY_SIZE(slf3s_variants); i++) { + if (buf[SLF3S_PRODUCT_SUBTYPE_BYTE] != + slf3s_variants[i].sub_type) + continue; + + if (sf->variant && sf->variant != &slf3s_variants[i]) + dev_dbg(&client->dev, + "DT compatible says %s but sub-type 0x%02x suggests %s\n", + sf->variant->name, + buf[SLF3S_PRODUCT_SUBTYPE_BYTE], + slf3s_variants[i].name); + else if (!sf->variant) + sf->variant = &slf3s_variants[i]; + return 0; + } + + if (sf->variant) { + dev_dbg(&client->dev, + "unknown SLF3S sub-type 0x%02x, trusting DT compatible %s\n", + buf[SLF3S_PRODUCT_SUBTYPE_BYTE], sf->variant->name); + return 0; + } + + dev_dbg(&client->dev, "unknown SLF3S sub-type 0x%02x\n", + buf[SLF3S_PRODUCT_SUBTYPE_BYTE]); + return -ENODEV; +} + +static int slf3s_read_sample(struct slf3s_data *sf, int *flow, int *temp) +{ + u8 buf[SLF3S_MEAS_LEN]; + int ret; + + ret = i2c_master_recv(sf->client, buf, sizeof(buf)); + if (ret < 0) + return ret; + if (ret != sizeof(buf)) + return -EIO; + + for (unsigned int i = 0; i < SLF3S_MEAS_LEN; i += 3) { + if (!slf3s_crc_valid(sf, &buf[i])) + return -EIO; + } + + *flow = sign_extend32(get_unaligned_be16(&buf[0]), 15); + *temp = sign_extend32(get_unaligned_be16(&buf[3]), 15); + return 0; +} + +static const struct iio_chan_spec slf3s_channels[] = { + { + .type = IIO_VOLUMEFLOW, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + }, + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + }, +}; + +static int slf3s_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct slf3s_data *sf = iio_priv(indio_dev); + int flow, temp, ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (!iio_device_claim_direct(indio_dev)) + return -EBUSY; + + ret = slf3s_read_sample(sf, &flow, &temp); + iio_device_release_direct(indio_dev); + if (ret) + return ret; + + *val = (chan->type == IIO_VOLUMEFLOW) ? flow : temp; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (chan->type == IIO_VOLUMEFLOW) { + *val = sf->variant->scale_num; + *val2 = sf->variant->scale_den; + return IIO_VAL_FRACTIONAL; + } + *val = SLF3S_TEMP_SCALE_MILLIC; + return IIO_VAL_INT; + default: + return -EINVAL; + } +} + +static const struct iio_info slf3s_info = { + .read_raw = slf3s_read_raw, +}; + +static void slf3s_stop_meas(void *data) +{ + struct slf3s_data *sf = data; + + slf3s_send_cmd(sf->client, slf3s_cmd_stop_meas); +} + +static int slf3s_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct iio_dev *indio_dev; + struct slf3s_data *sf; + const u8 *start_cmd = slf3s_cmd_start_water; + const char *medium; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*sf)); + if (!indio_dev) + return -ENOMEM; + + sf = iio_priv(indio_dev); + sf->client = client; + sf->variant = i2c_get_match_data(client); + crc8_populate_msb(sf->crc_table, SLF3S_CRC8_POLY); + + ret = devm_regulator_get_enable(dev, "vdd"); + if (ret) + return dev_err_probe(dev, ret, "failed to enable vdd supply\n"); + + ret = slf3s_detect_variant(sf); + if (ret) + return dev_err_probe(dev, ret, "product info read failed\n"); + + ret = device_property_read_string(dev, "sensirion,medium", &medium); + if (!ret) { + if (!strcmp(medium, "ipa")) + start_cmd = slf3s_cmd_start_ipa; + else if (strcmp(medium, "water")) + return dev_err_probe(dev, -EINVAL, + "unknown sensirion,medium '%s'\n", + medium); + } + + ret = slf3s_send_cmd(client, start_cmd); + if (ret) + return dev_err_probe(dev, ret, + "failed to start measurement\n"); + + fsleep(SLF3S_MEAS_START_DELAY_US); + + ret = devm_add_action_or_reset(dev, slf3s_stop_meas, sf); + if (ret) + return ret; + + indio_dev->name = sf->variant->name; + indio_dev->channels = slf3s_channels; + indio_dev->num_channels = ARRAY_SIZE(slf3s_channels); + indio_dev->info = &slf3s_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct i2c_device_id slf3s_id[] = { + { .name = "slf3s-0600f", .driver_data = (kernel_ulong_t)&slf3s_variants[0] }, + { .name = "slf3s-1300f", .driver_data = (kernel_ulong_t)&slf3s_variants[1] }, + { .name = "slf3s-4000b", .driver_data = (kernel_ulong_t)&slf3s_variants[2] }, + { .name = "slf3s" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, slf3s_id); + +static const struct of_device_id slf3s_of_match[] = { + { .compatible = "sensirion,slf3s-0600f", .data = &slf3s_variants[0] }, + { .compatible = "sensirion,slf3s-1300f", .data = &slf3s_variants[1] }, + { .compatible = "sensirion,slf3s-4000b", .data = &slf3s_variants[2] }, + { .compatible = "sensirion,slf3s" }, + { } +}; +MODULE_DEVICE_TABLE(of, slf3s_of_match); + +static struct i2c_driver slf3s_driver = { + .driver = { + .name = "slf3s", + .of_match_table = slf3s_of_match, + }, + .probe = slf3s_probe, + .id_table = slf3s_id, +}; +module_i2c_driver(slf3s_driver); + +MODULE_AUTHOR("Wadim Mueller "); +MODULE_DESCRIPTION("Sensirion SLF3S liquid flow sensor driver"); +MODULE_LICENSE("GPL"); -- 2.52.0