On Mon, 12 Apr 2021 10:50:56 +0300 Tomas Melin <tomas.melin@xxxxxxxxxxx> wrote: > Add initial support for Murata SCA3300 3-axis industrial > accelerometer with digital SPI interface. This device also > provides a temperature measurement. > > Device product page including datasheet can be found at: > https://www.murata.com/en-global/products/sensor/accel/sca3300 > > Signed-off-by: Tomas Melin <tomas.melin@xxxxxxxxxxx> Hi Tomas, Comments below. Thanks, Jonathan > --- > drivers/iio/accel/Kconfig | 13 ++ > drivers/iio/accel/Makefile | 1 + > drivers/iio/accel/sca3300.c | 434 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 448 insertions(+) > create mode 100644 drivers/iio/accel/sca3300.c > > diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig > index cceda3cecbcf..0dbf7b648e8a 100644 > --- a/drivers/iio/accel/Kconfig > +++ b/drivers/iio/accel/Kconfig > @@ -450,6 +450,19 @@ config SCA3000 > To compile this driver as a module, say M here: the module will be > called sca3000. > > +config SCA3300 > + tristate "Murata SCA3300 3-Axis Accelerometer Driver" > + depends on SPI > + select CRC8 > + select IIO_BUFFER > + select IIO_TRIGGERED_BUFFER > + help > + Say yes here to build support for Murata SCA3300 3-Axis > + accelerometer. > + > + To compile this driver as a module, choose M here: the module will be > + called sca3300. > + > config STK8312 > tristate "Sensortek STK8312 3-Axis Accelerometer Driver" > depends on I2C > diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile > index 32cd1342a31a..4b56527a2b97 100644 > --- a/drivers/iio/accel/Makefile > +++ b/drivers/iio/accel/Makefile > @@ -50,6 +50,7 @@ obj-$(CONFIG_MXC4005) += mxc4005.o > obj-$(CONFIG_MXC6255) += mxc6255.o > > obj-$(CONFIG_SCA3000) += sca3000.o > +obj-$(CONFIG_SCA3300) += sca3300.o > > obj-$(CONFIG_STK8312) += stk8312.o > obj-$(CONFIG_STK8BA50) += stk8ba50.o > diff --git a/drivers/iio/accel/sca3300.c b/drivers/iio/accel/sca3300.c > new file mode 100644 > index 000000000000..112fb88ecd3a > --- /dev/null > +++ b/drivers/iio/accel/sca3300.c > @@ -0,0 +1,434 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) Vaisala Oyj. All rights reserved. Give a year for the copyright notice if you can. > + */ > +#include <linux/crc8.h> > +#include <linux/delay.h> > +#include <linux/iio/buffer.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/iio/trigger_consumer.h> > +#include <linux/iio/triggered_buffer.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/spi/spi.h> > + > +#define SCA3300_ALIAS "sca3300" > + > +#define SCA3300_REG_STATUS 0x6 > +#define SCA3300_REG_MODE 0xd > +#define SCA3300_REG_WHOAMI 0x10 > +#define SCA3300_VALUE_SW_RESET 0x20 > +#define SCA3300_CRC8_POLYNOMIAL 0x1d > +#define SCA3300_X_READ 0 I wouldn't bother defining this. > +#define SCA3300_X_WRITE BIT(7) Even this one is something I'd just put inline with a comment. > +#define SCA3300_DEVICE_ID 0x51 > +#define SCA3300_RS_ERROR 0x3 > + > +enum sca3300_scan_indexes { > + SCA3300_ACC_X = 0, > + SCA3300_ACC_Y, > + SCA3300_ACC_Z, > + SCA3300_TEMP, > + SCA3300_TIMESTAMP, > +}; > + > +#define SCA3300_ACCEL_CHANNEL(index, reg, axis) { \ > + .type = IIO_ACCEL, \ > + .address = reg, \ > + .modified = 1, \ > + .channel2 = IIO_MOD_##axis, \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ > + BIT(IIO_CHAN_INFO_PROCESSED), \ As mentioned below, don't provide PROCESSED. Userspace is better at handling the conversion so leave it to them. > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > + .scan_index = index, \ > + .scan_type = { \ > + .sign = 's', \ > + .realbits = 16, \ > + .storagebits = 16, \ > + .shift = 0, \ > + .endianness = IIO_CPU, \ > + }, \ > + } > + > +static const struct iio_chan_spec sca3300_channels[] = { > + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_X, 0x1, X), > + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Y, 0x2, Y), > + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Z, 0x3, Z), > + { > + .type = IIO_TEMP, > + .address = 0x5, > + .scan_index = SCA3300_TEMP, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + .scan_type = { > + .sign = 's', > + .realbits = 16, > + .storagebits = 16, > + .shift = 0, > + .endianness = IIO_CPU, > + }, > + }, > + IIO_CHAN_SOFT_TIMESTAMP(4), > +}; > + > +static const int sca3300_accel_scale[] = {2700, 1350, 5400, 5400}; > + > +static const unsigned long sca3300_scan_masks[] = { > + BIT(SCA3300_ACC_X) | BIT(SCA3300_ACC_Y) | BIT(SCA3300_ACC_Z) | > + BIT(SCA3300_TEMP), > + 0}; > + > +/** > + * SCA3300 device data run scripts/kernel-doc over the file and fix the warnings + errors. > + * > + * @spi SPI device structure > + * @opmode Device operation mode > + * @lock Data buffer lock > + * @txbuf Transmit buffer > + * @rxbuf Receive buffer > + * @scan Triggered buffer. Four channel 16-bit data + 64-bit timestamp > + */ > +struct sca3300_data { > + struct spi_device *spi; > + u32 opmode; > + struct mutex lock; > + u8 txbuf[4]; > + u8 rxbuf[4]; > + struct { > + s16 channels[4]; > + s64 ts __aligned(sizeof(s64)); > + } scan; > +}; > + > +DECLARE_CRC8_TABLE(sca3300_crc_table); > + > +static int sca3300_transfer(struct sca3300_data *sca_data, int *val) > +{ > + struct spi_delay delay = {.value = 10, .unit = SPI_DELAY_UNIT_USECS}; > + int32_t ret; > + int rs; > + u8 crc; > + struct spi_transfer xfers[2] = { > + { > + .tx_buf = sca_data->txbuf, > + .rx_buf = NULL, > + .len = ARRAY_SIZE(sca_data->txbuf), > + .delay = delay, > + .cs_change = 1, > + }, > + { > + .tx_buf = NULL, > + .rx_buf = sca_data->rxbuf, > + .len = ARRAY_SIZE(sca_data->rxbuf), > + .delay = delay, > + .cs_change = 0, > + } > + }; > + > + /* inverted crc value as described in device data sheet */ > + crc = ~crc8(sca3300_crc_table, &sca_data->txbuf[0], 3, CRC8_INIT_VALUE); > + sca_data->txbuf[3] = crc; > + > + ret = spi_sync_transfer(sca_data->spi, xfers, 2); Use ARRAY_SIZE(xfers) instead of 2. > + if (ret < 0) { > + dev_err(&sca_data->spi->dev, > + "transfer error, error: %d\n", ret); > + return -EIO; > + } > + > + crc = ~crc8(sca3300_crc_table, &sca_data->rxbuf[0], 3, CRC8_INIT_VALUE); > + if (sca_data->rxbuf[3] != crc) { > + dev_err(&sca_data->spi->dev, "CRC checksum mismatch"); > + return -EIO; > + } > + > + /* get return status */ > + rs = sca_data->rxbuf[0] & 0x03; > + if (rs == SCA3300_RS_ERROR) > + return rs; > + > + *val = (s16)(sca_data->rxbuf[2] | (sca_data->rxbuf[1] << 8)); Preference for an unaligned endian conversion here and explicit sign extend e.g something like sign_extend32(get_unaligned_le16(&sca_data->rxbuf[1]), 15) > + > + return 0; > +} > + > +static int sca3300_read_reg(struct sca3300_data *sca_data, u8 reg, int *val) > +{ > + int ret; > + > + mutex_lock(&sca_data->lock); > + sca_data->txbuf[0] = SCA3300_X_READ | (reg << 2); > + ret = sca3300_transfer(sca_data, val); > + if (ret > 0) { > + sca_data->txbuf[0] = SCA3300_X_READ | (SCA3300_REG_STATUS << 2); > + ret = sca3300_transfer(sca_data, val); > + /* status 0 = startup, 0x2 = mode change */ > + if (ret > 0 && *val != 0 && *val != 0x2) { > + dev_err_ratelimited(&sca_data->spi->dev, > + "device status: %x\n", > + (u16)*val); > + mutex_unlock(&sca_data->lock); > + return -EIO; > + } > + if (ret > 0) > + ret = 0; > + } > + mutex_unlock(&sca_data->lock); > + > + return ret; > +} > + > +static int sca3300_write_reg(struct sca3300_data *sca_data, u8 reg, int val) > +{ > + int reg_val = 0; > + int ret; > + > + mutex_lock(&sca_data->lock); > + sca_data->txbuf[0] = SCA3300_X_WRITE | (reg << 2); > + sca_data->txbuf[1] = val >> 8; > + sca_data->txbuf[2] = val & 0xFF; Prefer (Slightly) an unaligned put. > + ret = sca3300_transfer(sca_data, ®_val); > + if (ret > 0) { Factor this error handling out to another function, plus trigger it from an appropriate standard error code rather than a positive return value. > + sca_data->txbuf[0] = SCA3300_X_READ | (SCA3300_REG_STATUS << 2); > + ret = sca3300_transfer(sca_data, ®_val); > + /* status 0 = startup, 0x2 = mode change */ > + if (ret > 0 && reg_val != 0 && reg_val != 0x2) { > + dev_err_ratelimited(&sca_data->spi->dev, > + "device status: %x\n", > + (u16)reg_val); > + mutex_unlock(&sca_data->lock); > + return -EIO; > + } > + if (ret > 0) > + ret = 0; Whenever you get this sort of juggling it rather implies your design is less than ideal. > + } > + mutex_unlock(&sca_data->lock); > + > + return ret; > +} > + > +static int sca3300_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct sca3300_data *data = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_SCALE: > + if (val < 0 || val > 3) > + return -EINVAL; No. Scale values need to be the value of 1LSB not a random integer that requires you to look up the datasheet. > + return sca3300_write_reg(data, SCA3300_REG_MODE, val); > + default: > + return -EINVAL; > + } > +} > + > +static int sca3300_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct sca3300_data *data = iio_priv(indio_dev); > + int ret; > + int reg_val; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + ret = sca3300_read_reg(data, chan->address, val); > + if (ret < 0) > + return ret; > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + ret = sca3300_read_reg(data, SCA3300_REG_MODE, ®_val); > + if (ret < 0) > + return ret; > + *val = sca3300_accel_scale[reg_val]; Scale is very very rarely an integer value which makes me wonder what you are returning here... It should be the multiplier needed to take the raw value to a reading in m/sec^2 Given you use it as fractional below, I'm guessing this is 1/scale_value? > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_PROCESSED: Don't provide processed here. Userspace needs to do the conversion itself (and given it has floating point easily available will probably do a better job than we can). I'm assuming the mode can't autonomously change? > + ret = sca3300_read_reg(data, SCA3300_REG_MODE, ®_val); > + if (ret < 0) > + return ret; > + *val2 = sca3300_accel_scale[reg_val]; > + ret = sca3300_read_reg(data, chan->address, val); > + if (ret < 0) > + return ret; > + return IIO_VAL_FRACTIONAL; > + default: > + return -EINVAL; > + } > +} > + > +static irqreturn_t sca3300_trigger_handler(int irq, void *p) > +{ > + struct iio_poll_func *pf = p; > + struct iio_dev *indio_dev = pf->indio_dev; > + struct sca3300_data *data = iio_priv(indio_dev); > + s64 time_ns = iio_get_time_ns(indio_dev); Is the timestamp at the start more accurate that that at the end of reading the channels? If not, just put this inline in the iio_push_to_buffers_with_timestamp() call. > + int bit, ret, val, i = 0; > + > + for_each_set_bit(bit, indio_dev->active_scan_mask, > + indio_dev->masklength) { > + ret = sca3300_read_reg(data, sca3300_channels[bit].address, > + &val); > + if (ret < 0) Given we can't return an error code from interrupt handlers, it is usually a good idea to print something to the log. Otherwise we get missing data with no idea of why.. > + goto out; > + if (ARRAY_SIZE(data->scan.channels) > i) How could this not be true? If it's always true, don't bother checking i. > + ((s16 *)data->scan.channels)[i++] = val; > + } > + > + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, time_ns); > +out: > + iio_trigger_notify_done(indio_dev->trig); > + > + return IRQ_HANDLED; > +} > + > +static int sca3300_init(struct sca3300_data *sca_data, > + struct iio_dev *indio_dev) > +{ > + int ret; > + int value = 0; > + > + if (sca_data->opmode < 1 || sca_data->opmode > 4) > + return -EINVAL; Whilst this is going anyway, better to check that next to where it is read so we drop out immediately rather than buried in this function. > + > + ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE, > + SCA3300_VALUE_SW_RESET); > + if (ret != 0) > + return ret; For sleeps, good to reference which section in data sheet gives the timing. > + usleep_range(2e3, 10e3); > + > + ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE, > + sca_data->opmode - 1); > + if (ret != 0) if (ret) see below. > + return ret; > + msleep(100); Again, document where the time comes from. Saves reviewers time if they want to check it. (I'm too lazy :) > + ret = sca3300_read_reg(sca_data, SCA3300_REG_WHOAMI, &value); > + if (ret != 0) if (ret) is more idiomatic in kernel code. > + return ret; > + > + if (value != SCA3300_DEVICE_ID) { > + dev_err(&sca_data->spi->dev, "device id not expected value\n"); Perhaps useful to print what was expected and what was seen. Maybe it's a new variant and this might help the user to identify that and add it to the driver. > + return -EIO; -EINVAL probably more appropriate return. > + } > + return 0; > +} > + > +static int sca3300_debugfs_reg_access(struct iio_dev *indio_dev, > + unsigned int reg, unsigned int writeval, > + unsigned int *readval) > +{ > + struct sca3300_data *data = iio_priv(indio_dev); > + int value; > + int ret; > + > + if (reg > 0x1f) Use a define that names that register. > + return -EINVAL; > + > + if (!readval) > + return sca3300_write_reg(data, reg, writeval); > + > + ret = sca3300_read_reg(data, reg, &value); > + if (ret < 0) > + return ret; > + > + *readval = (unsigned int)value; > + > + return 0; > +} > + > +static const struct iio_info sca3300_info = { > + .read_raw = sca3300_read_raw, > + .write_raw = sca3300_write_raw, > + .debugfs_reg_access = &sca3300_debugfs_reg_access, > +}; > + > +static int sca3300_probe(struct spi_device *spi) > +{ > + struct sca3300_data *sca_data; > + struct iio_dev *indio_dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*sca_data)); > + if (!indio_dev) { > + dev_err(&spi->dev, > + "failed to allocate memory for iio device\n"); > + return -ENOMEM; > + } > + > + sca_data = iio_priv(indio_dev); > + mutex_init(&sca_data->lock); > + sca_data->spi = spi; > + spi_set_drvdata(spi, indio_dev); Won't be used once using devm as below and remove() is dropped, so drop this. > + > + crc8_populate_msb(sca3300_crc_table, SCA3300_CRC8_POLYNOMIAL); > + > + indio_dev->dev.parent = &spi->dev; > + indio_dev->info = &sca3300_info; > + indio_dev->name = SCA3300_ALIAS; > + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED; BUFFER_TRIGGERED bit now set by iio_triggered_buffer_setup() so shouldn't be ehre as well. > + indio_dev->channels = sca3300_channels; > + indio_dev->num_channels = ARRAY_SIZE(sca3300_channels); > + indio_dev->available_scan_masks = sca3300_scan_masks; > + > + if (spi->dev.of_node) { > + ret = of_property_read_u32(spi->dev.of_node, "murata,opmode", Please use generic firmware access calls rather than the of specific ones. That lets us get ACPI support for free :) As per the binding review however, this one needs to go in favour of userspace control of scale + filter frequencies / sampling freq. > + &sca_data->opmode); > + if (ret < 0) > + return ret; > + } > + > + ret = sca3300_init(sca_data, indio_dev); > + if (ret < 0) { > + dev_err(&spi->dev, "failed to init device, error: %d\n", ret); > + return ret; > + } > + > + ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time, > + sca3300_trigger_handler, NULL); devm_iio_triggered_buffer_setup() and you can drop the manual cleanup in remove() and hence drop remove() entirely as nothing else left. > + if (ret < 0) { > + dev_err(&spi->dev, > + "iio triggered buffer setup failed, error: %d\n", ret); > + return ret; > + } > + > + ret = devm_iio_device_register(&spi->dev, indio_dev); > + if (ret < 0) { > + dev_err(&spi->dev, "iio device register failed, error: %d\n", > + ret); > + iio_triggered_buffer_cleanup(indio_dev); With devm above, no need to manually clean this up. > + return ret; > + } > + > + return 0; > +} > + > +static int sca3300_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + > + iio_triggered_buffer_cleanup(indio_dev); > + return 0; > +} > + > +static const struct of_device_id sca3300_dt_ids[] = { > + { .compatible = "murata,sca3300"}, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, sca3300_dt_ids); > + > +static struct spi_driver sca3300_driver = { > + .driver = { > + .name = SCA3300_ALIAS, > + .owner = THIS_MODULE, > + .of_match_table = of_match_ptr(sca3300_dt_ids), > + }, > + > + .probe = sca3300_probe, > + .remove = sca3300_remove, > +}; > + > +module_spi_driver(sca3300_driver); > + > +MODULE_AUTHOR("Tomas Melin <tomas.melin@xxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Murata SCA3300 SPI Accelerometer"); > +MODULE_LICENSE("GPL v2");
