RE: [PATCH 1/3] iio: pressure: Add driver for DLH pressure sensors

Denis, Tomislav AVL DiTEST
2019-11-15T07:36:56Z

Hi Jonathan,

Thanks for the fast review. V2 patches coming soon.

Tomislav

> On Thu, 14 Nov 2019 11:09:06 +0100
> <tomislav.denis@avl.com> wrote:
>
> > From: Tomislav Denis <tomislav.denis@avl.com>
> >
> > All Sensors DLH is series of low voltage digital pressure sensors.
> > Additionally to pressure value sensors deliver a temperature value.
> > Sensors can be accessed over I2C and SPI, this driver supports only
> > I2C access.
> >
> > Signed-off-by: Tomislav Denis <tomislav.denis@avl.com>
> Hi Tomislav,
>
> A few comments inline. Please check the units of the output against the IIO
> ABI docs. Some IIO ABI units are non obvious unfortunately!
>
> Thanks,
>
> Jonathan
>
> > ---
> > MAINTAINERS | 7 +
> > drivers/iio/pressure/Kconfig | 12 ++
> > drivers/iio/pressure/Makefile | 1 +
> > drivers/iio/pressure/dlh-i2c.c | 322
> > +++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 342 insertions(+)
> > create mode 100644 drivers/iio/pressure/dlh-i2c.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS index 8323258..2a08923 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -668,6 +668,13 @@ S: Maintained
> > F: Documentation/i2c/busses/i2c-ali1563.rst
> > F: drivers/i2c/busses/i2c-ali1563.c
> >
> > +ALL SENSORS DLH SERIES PRESSURE SENSORS DRIVER
> > +M: Tomislav Denis <tomislav.denis@avl.com>
> > +W: http://www.allsensors.com/cad/DS-0355_Rev_B.PDF
> The specific path is likely to bit rot.
> So either drop the entry entirely or perhaps
> W http://www.allsensors.com/cad/DS-0355_Rev_B.PDF
> > +S: Maintained
> > +L: linux-iio@vger.kernel.org
> > +F: drivers/iio/pressure/dlh-i2c.c
> > +
> > ALLEGRO DVT VIDEO IP CORE DRIVER
> > M: Michael Tretter <m.tretter@pengutronix.de>
> > R: Pengutronix Kernel Team <kernel@pengutronix.de>
> > diff --git a/drivers/iio/pressure/Kconfig
> > b/drivers/iio/pressure/Kconfig index ba420e4..504de3e 100644
> > --- a/drivers/iio/pressure/Kconfig
> > +++ b/drivers/iio/pressure/Kconfig
> > @@ -53,6 +53,18 @@ config IIO_CROS_EC_BARO
> > To compile this driver as a module, choose M here: the module
> > will be called cros_ec_baro.
> >
> > +config DLH_I2C
> > + tristate "All Sensors DLH series low voltage digital pressure sensors"
> > + depends on I2C
> > + select IIO_BUFFER
> > + select IIO_TRIGGERED_BUFFER
> > + help
> > + Say yes here to build support for the All Sensors DLH series
> > + pressure sensors driver.
> > +
> > + To compile this driver as a module, choose M here: the module
> > + will be called dlh-i2c.
> > +
> > config DPS310
> > tristate "Infineon DPS310 pressure and temperature sensor"
> > depends on I2C
> > diff --git a/drivers/iio/pressure/Makefile
> > b/drivers/iio/pressure/Makefile index d8f5ace..1851a36 100644
> > --- a/drivers/iio/pressure/Makefile
> > +++ b/drivers/iio/pressure/Makefile
> > @@ -9,6 +9,7 @@ obj-$(CONFIG_BMP280) += bmp280.o bmp280-objs :=
> > bmp280-core.o bmp280-regmap.o
> > obj-$(CONFIG_BMP280_I2C) += bmp280-i2c.o
> > obj-$(CONFIG_BMP280_SPI) += bmp280-spi.o
> > +obj-$(CONFIG_DLH_I2C) += dlh-i2c.o
> > obj-$(CONFIG_DPS310) += dps310.o
> > obj-$(CONFIG_IIO_CROS_EC_BARO) += cros_ec_baro.o
> > obj-$(CONFIG_HID_SENSOR_PRESS) += hid-sensor-press.o
> > diff --git a/drivers/iio/pressure/dlh-i2c.c
> > b/drivers/iio/pressure/dlh-i2c.c new file mode 100644 index
> > 0000000..4ef13c2
> > --- /dev/null
> > +++ b/drivers/iio/pressure/dlh-i2c.c
> > @@ -0,0 +1,322 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * All Sensors DLH series low voltage digital pressure sensors
> > + *
> > + * Copyright (c) 2019 AVL DiTEST GmbH
> > + * Tomislav Denis <tomislav.denis@avl.com>
> > + *
> > + * Datasheet: http://www.allsensors.com/cad/DS-0355_Rev_B.PDF
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/buffer.h>
> > +#include <linux/iio/trigger_consumer.h> #include
> > +<linux/iio/triggered_buffer.h>
> > +
> > +/* Commands */
> > +#define DLH_START_SINGLE 0xAA
> > +
> > +/* Status bits */
> > +#define DLH_STATUS_OK 0x40
> > +
> > +/* DLH data format */
> > +#define DLH_NUM_READ_BYTES 7
> > +#define DLH_NUM_DATA_BYTES 3
> > +#define DLH_NUM_PR_BITS 24
> > +#define DLH_NUM_TEMP_BITS 24
> > +
> > +/* DLH timings */
> > +#define DLH_SINGLE_DUT_MS 5
> > +
> > +enum dhl_ids {
> > + dlhl60d,
> > + dlhl60g,
> > +};
> > +
> > +struct dlh_info {
> > + u8 osdig; /* digital offset factor */
> > + unsigned int fss; /* full scale span (inch H2O) */
> > +};
> > +
> > +struct dlh_state {
> > + struct i2c_client *client;
> > + struct dlh_info info;
> > + u8 rx_buf[DLH_NUM_READ_BYTES] ____cacheline_aligned; };
> > +
> > +static struct dlh_info dlh_info_tbl[] = {
> > + [dlhl60d] = {
> > + .osdig = 2,
> > + .fss = 120,
> > + },
> > + [dlhl60g] = {
> > + .osdig = 10,
> > + .fss = 60,
> > + },
> > +};
> > +
> > +static int dlh_i2c_read_direct(struct dlh_state *st,
> > + unsigned int *pressure, unsigned int *temperature) {
> > + int ret;
> > +
> > + ret = i2c_smbus_write_byte(st->client, DLH_START_SINGLE);
> > + if (ret) {
> > + dev_err(&st->client->dev,
> > + "%s: I2C write byte failed\n", __func__);
> > + return ret;
> > + }
> > +
> > + mdelay(DLH_SINGLE_DUT_MS);
> > +
> > + ret = i2c_master_recv(st->client, st->rx_buf,
> DLH_NUM_READ_BYTES);
> > + if (ret < 0) {
> > + dev_err(&st->client->dev,
> > + "%s: I2C read block failed\n", __func__);
> > + return ret;
> > + }
> > +
> > + if (st->rx_buf[0] != DLH_STATUS_OK) {
> > + dev_err(&st->client->dev,
> > + "%s: invalid status 0x%02x\n", __func__, st-
> >rx_buf[0]);
> > + return -EBUSY;
> > + }
> > +
> > + *pressure = be32_to_cpup((u32 *)&st->rx_buf[1]) >> 8;
> > + *temperature = be32_to_cpup((u32 *)&st->rx_buf[3]) &
> > + GENMASK(DLH_NUM_TEMP_BITS - 1, 0);
> > +
> > + return 0;
> > +}
> > +
> > +static int dlh_i2c_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *channel, int *value,
> > + int *value2, long mask)
> > +{
> > + struct dlh_state *st = iio_priv(indio_dev);
> > + unsigned int pressure, temperature;
> > + int ret;
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + if (iio_buffer_enabled(indio_dev))
> > + return -EBUSY;
> > +
> > + ret = iio_device_claim_direct_mode(indio_dev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = dlh_i2c_read_direct(st, &pressure, &temperature);
> > + iio_device_release_direct_mode(indio_dev);
> > + if (ret)
> > + return ret;
> > +
> > + switch (channel->type) {
> > + case IIO_PRESSURE: /* inch H2O */
>
> I'm guessing the scale converts that to kilopascals as per
> Documentation/ABI/testing/sysfs-bus-iio?
>
> > + *value = pressure;
> > + return IIO_VAL_INT;
> > +
> > + case IIO_TEMP: /* degrees Celsius */
>
> Base units in IIO for temperature are milli degress Celsius.
>
> > + *value = temperature;
> > + return IIO_VAL_INT;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > + case IIO_CHAN_INFO_SCALE:
> > + switch (channel->type) {
> > + case IIO_PRESSURE:
> > + *value = 125 * st->info.fss;
> > + *value2 = 100 * (1 << DLH_NUM_PR_BITS);
> > + return IIO_VAL_FRACTIONAL;
> > +
> > + case IIO_TEMP:
> > + *value = 125;
> > + *value2 = DLH_NUM_TEMP_BITS;
> > + return IIO_VAL_FRACTIONAL_LOG2;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > + case IIO_CHAN_INFO_OFFSET:
> > + switch (channel->type) {
> > + case IIO_PRESSURE:
> > + *value = -125 * st->info.fss;
> > + *value2 = 100 * st->info.osdig;
> > + return IIO_VAL_FRACTIONAL;
> > +
> > + case IIO_TEMP:
> > + *value = -40;
> > + return IIO_VAL_INT;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> default:
> return -EINVAL;
>
> > + }
> > +
> Drop the following. One of the standard build bots complains about this and
> it is sensible to ensure it was deliberate that not all cases were handled in
> that switch statement.
> > + return -EINVAL;
> > +}
> > +
> > +static const struct iio_info dlh_i2c_info = {
> > + .read_raw = dlh_i2c_read_raw,
> > +};
> > +
> > +static const struct iio_chan_spec dlh_i2c_channels[] = {
> > + {
> > + .type = IIO_PRESSURE,
> > + .indexed = 1,
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> > + .info_mask_shared_by_type =
> > + BIT(IIO_CHAN_INFO_SCALE) |
> > + BIT(IIO_CHAN_INFO_OFFSET),
> > + .scan_index = 0,
> > + .scan_type = {
> > + .sign = 'u',
> > + .realbits = DLH_NUM_PR_BITS,
> > + .storagebits = 32,
> > + .shift = 8,
> > + .endianness = IIO_BE,
> > + },
> > + }, {
> > + .type = IIO_TEMP,
> > + .indexed = 1,
>
> If setting indexed, even though the default is 0, should probably provide the
> .channel = 0, to make that explicit.
>
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> > + .info_mask_shared_by_type =
> > + BIT(IIO_CHAN_INFO_SCALE) |
> > + BIT(IIO_CHAN_INFO_OFFSET),
> > + .scan_index = 1,
> > + .scan_type = {
> > + .sign = 'u',
> > + .realbits = DLH_NUM_TEMP_BITS,
> > + .storagebits = 32,
> > + .shift = 8,
> > + .endianness = IIO_BE,
> > + },
> > + }
> > +};
> > +
> > +static irqreturn_t dlh_i2c_trigger_handler(int irq, void *private) {
> > + struct iio_poll_func *pf = (struct iio_poll_func *)private;
> No need to add explicit cast for pointers of type void *. The c spec allows
> simply
>
> struct iio_poll_func *pf = private;
>
> > + struct iio_dev *indio_dev = pf->indio_dev;
> > + struct dlh_state *st = iio_priv(indio_dev);
> > + int ret;
> > + unsigned int chn, i = 0;
> > + __be32 tmp_buf[2];
> > +
> > + ret = i2c_master_recv(st->client, st->rx_buf,
> DLH_NUM_READ_BYTES);
> > + if (ret < 0) {
> > + dev_err(&st->client->dev,
> > + "%s: I2C read block failed\n", __func__);
> > + goto out;
> > + }
> > +
> > + if (st->rx_buf[0] != DLH_STATUS_OK) {
> > + dev_err(&st->client->dev,
> > + "%s: invalid status 0x%02x\n", __func__, st-
> >rx_buf[0]);
> > + goto out;
> > + }
> > +
> > + ret = i2c_smbus_write_byte(st->client, DLH_START_SINGLE);
> > + if (ret) {
> > + dev_err(&st->client->dev,
> > + "%s: I2C write byte failed\n", __func__);
> > + goto out;
> > + }
>
> If I understand the logic here correctly, you are triggering the next capture as
> part of the previous one. This doesn't sound right as we are using an
> external trigger. Imagine.
>
> Trigger1 - reads whatever is currently in buffer and starts next sample.
> Wait 5 minutes
> Trigger2 - reads whatever was captured just after trigger1 not fresh data as
> we might expect.
>
> In particular I suspect you get random stale data for the first read after
> starting the buffer.
>
> The flow should be.
>
> Trigger1. Send the DLH_START_SINGLE;
> poll or wait for interrupt to signal completion of this reading.
> Read data.
>
> Wait for 5 minutes
> Trigger 2. Send the DLH_START_SINGLE;
> poll or wait for interrupt to signal completion of this reading.
> Read data.
>
> That should guarantee fresh data whatever the spacing of triggers.
>
> If you want to basically get data as quick as possible, the loop trigger will
> ensure that you call the start asap after the prevous read.
>
> > +
> > + for_each_set_bit(chn, indio_dev->active_scan_mask,
> > + indio_dev->masklength) {
> > + memcpy(tmp_buf + i,
> > + &st->rx_buf[1] + chn * DLH_NUM_DATA_BYTES,
> > + DLH_NUM_DATA_BYTES);
> > + i++;
> > + }
> > +
> > + iio_push_to_buffers(indio_dev, tmp_buf);
> > +
> > +out:
> > + iio_trigger_notify_done(indio_dev->trig);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int dlh_i2c_probe(struct i2c_client *client,
> > + const struct i2c_device_id *id)
> > +{
> > + struct dlh_state *st;
> > + struct iio_dev *indio_dev;
> > + int ret;
> > +
> > + if (!i2c_check_functionality(client->adapter,
> > + I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE)) {
> > + dev_err(&client->dev,
> > + "adapter doesn't support required i2c
> functionality\n");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
> > + if (!indio_dev) {
> > + dev_err(&client->dev, "failed to allocate iio device\n");
> > + return -ENOMEM;
> > + }
> > +
> > + i2c_set_clientdata(client, indio_dev);
> > +
> > + st = iio_priv(indio_dev);
> > + st->info = dlh_info_tbl[id->driver_data];
> > + st->client = client;
> > +
> > + indio_dev->name = id->name;
> > + indio_dev->dev.parent = &client->dev;
> > + indio_dev->dev.of_node = client->dev.of_node;
> > + indio_dev->info = &dlh_i2c_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->channels = dlh_i2c_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(dlh_i2c_channels);
> > +
> > + ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
> > + &iio_pollfunc_store_time, &dlh_i2c_trigger_handler, NULL);
> > + if (ret) {
> > + dev_err(&client->dev, "failed to setup iio buffer\n");
> > + return ret;
> > + }
> > +
> > + ret = devm_iio_device_register(&client->dev, indio_dev);
> > + if (ret) {
> > + dev_err(&client->dev, "failed to register iio device\n");
> > + return ret;
> Drop the return ret; out of the brackets as then we don't need the return 0.
>
> if (ret)
> dev_err(...)
>
> return ret;
> }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id dlh_i2c_of_match[] = {
> > + { .compatible = "asc,dlhl60d" },
> > + { .compatible = "asc,dlhl60g" },
> > + {}
> > +};
> > +MODULE_DEVICE_TABLE(of, dlh_i2c_of_match);
> > +
> > +static const struct i2c_device_id dlh_i2c_id[] = {
> > + { "dlhl60d", dlhl60d },
> > + { "dlhl60g", dlhl60g },
> > + {}
> > +};
> > +MODULE_DEVICE_TABLE(i2c, dlh_i2c_id);
> > +
> > +static struct i2c_driver dlh_i2c_driver = {
> > + .driver = {
> > + .name = "dlh_i2c",
> > + .of_match_table = dlh_i2c_of_match,
> > + },
> > + .probe = dlh_i2c_probe,
> > + .id_table = dlh_i2c_id,
> > +};
> > +module_i2c_driver(dlh_i2c_driver);
> > +
> > +MODULE_AUTHOR("Tomislav Denis <tomislav.denis@avl.com>");
> > +MODULE_DESCRIPTION("Driver for All Sensors DLH series pressure
> > +sensors"); MODULE_LICENSE("GPL v2");
>