Re: [PATCH 2/2] iio: accel: Add support for Domintech DMARD06 accelerometer

Jonathan Cameron
2016-07-23T10:57:45Z

On 22/07/16 00:41, Peter Meerwald-Stadler wrote:
>
>> This patch add support for Domintech DMARD06 accelerometer.
>
> comments below
>
>> Domintech DMARD06 is a low-g tri-axial digital accelerometer for
>> cost-sensitive consumer application.
>>
>> Signed-off-by: Aleksei Mamlin <mamlinav@gmail.com>
I don't have anything to add here. Nice fairly clean first version.
>> ---
>> .../devicetree/bindings/iio/accel/dmard06.txt | 17 ++
>> drivers/iio/accel/Kconfig | 11 ++
>> drivers/iio/accel/Makefile | 1 +
>> drivers/iio/accel/dmard06.c | 219 +++++++++++++++++++++
>> 4 files changed, 248 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/iio/accel/dmard06.txt
>> create mode 100644 drivers/iio/accel/dmard06.c
>>
>> diff --git a/Documentation/devicetree/bindings/iio/accel/dmard06.txt b/Documentation/devicetree/bindings/iio/accel/dmard06.txt
>> new file mode 100644
>> index 0000000..cc2231a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/accel/dmard06.txt
>> @@ -0,0 +1,17 @@
>> +Device tree bindings for Domintech DMARD06 acceletometer
>
> typo: accelerometer
>
>> +
>> +Required properties:
>> + - compatible : Should be "domintech,dmard06"
>> + - reg : I2C address of the chip. Should be 0x1c
>> +
>> +Example:
>> + &i2c1 {
>> + /* ... */
>> +
>> + accelerometer@1c {
>> + compatible = "domintech,dmard06";
>> + reg = <0x1c>;
>> + };
>> +
>> + /* ... */
>> + };
>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>> index e4a758c..abc8536 100644
>> --- a/drivers/iio/accel/Kconfig
>> +++ b/drivers/iio/accel/Kconfig
>> @@ -40,6 +40,17 @@ config BMC150_ACCEL_SPI
>> tristate
>> select REGMAP_SPI
>>
>> +config DMARD06
>> + tristate "Domintech DMARD06 Digital Accelerometer Driver"
>> + depends on OF || COMPILE_TEST
>> + depends on I2C
>> + help
>> + Say yes here to build support for the Domintech DMARD06 low-g
>> + tri-axial digital accelerometer connected via an I2C bus.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called dmard06.
>> +
>> config HID_SENSOR_ACCEL_3D
>> depends on HID_SENSOR_HUB
>> select IIO_BUFFER
>> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
>> index 71b6794..a96b269 100644
>> --- a/drivers/iio/accel/Makefile
>> +++ b/drivers/iio/accel/Makefile
>> @@ -7,6 +7,7 @@ obj-$(CONFIG_BMA180) += bma180.o
>> obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
>> obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
>> obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
>> +obj-$(CONFIG_DMARD06) += dmard06.o
>> obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
>> obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
>> obj-$(CONFIG_KXSD9) += kxsd9.o
>> diff --git a/drivers/iio/accel/dmard06.c b/drivers/iio/accel/dmard06.c
>> new file mode 100644
>> index 0000000..433e430
>> --- /dev/null
>> +++ b/drivers/iio/accel/dmard06.c
>> @@ -0,0 +1,219 @@
>> +/*
>> + * IIO driver for Domintech DMARD06 accelerometer
>> + *
>> + * Copyright (C) 2016 Aleksei Mamlin <mamlinav@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/i2c.h>
>> +#include <linux/iio/iio.h>
>> +
>> +struct dmard06_data {
>> + struct i2c_client *client;
>> +};
>> +
>> +#define DMARD06_DRV_NAME "dmard06"
>> +
>> +/* Device data registers */
>> +#define DMARD06_CHIP_ID_REG 0x0f
>> +#define DMARD06_TOUT_REG 0x40
>> +#define DMARD06_XOUT_REG 0x41
>> +#define DMARD06_YOUT_REG 0x42
>> +#define DMARD06_ZOUT_REG 0x43
>> +
>> +/* Device ID value */
>> +#define DMARD06_CHIP_ID 0x06
>> +
>> +/* Device values */
>> +#define DMARD06_AXIS_MAX_VAL 64
>> +#define DMARD06_AXIS_SCALE_VAL 31250
>> +#define DMARD06_TEMP_CENTER_VAL 25
>> +
>> +static int dmard06_i2c_read(struct i2c_client *client, u8 reg, u8 *buf)
>> +{
>> + int error;
>
> 'error' is a bit pessimistic, how about 'ret'? :-)
>
>> +
>
> can't use i2c_smbus_read_byte_data()?
>
>> + error = i2c_master_send(client, &reg, 1);
>> + if (unlikely(error < 0))
>> + return error;
>> +
>> + error = i2c_master_recv(client, buf, 1);
>> + if (unlikely(error < 0))
>> + return error;
>
> not sure if it is worth to annotate unlikely() here -- i2c is slooow
> locking is needed if you really need two i2c_master calls
>
>> + return 0;
>> +}
>> +
>> +static int dmard06_read_chip_id(struct dmard06_data *dmard06)
>> +{
>> + u8 buf;
>> + u8 chip_id;
>> + int error;
>> +
>> + error = dmard06_i2c_read(dmard06->client, DMARD06_CHIP_ID_REG, &buf);
>> + if (error) {
>> + dev_err(&dmard06->client->dev, "Failed to read chip id: %d\n",
>> + error);
>> + return error;
>> + }
>> +
>> + chip_id = (buf & 0x00ff);
>
> why? buf is u8 anyways
>
>> + if (chip_id != DMARD06_CHIP_ID) {
>> + dev_err(&dmard06->client->dev, "Invalid chip id: %02x\n",
>> + chip_id);
>> + return -EINVAL;
>
> often ENODEV is used for this case
>
>> + }
>> +
>> + dev_info(&dmard06->client->dev, "Found DMARD%02x chip\n", chip_id);
>
> we prefer silent probing of the driver, please don't clutter the log
>
>> +
>> + return 0;
>> +}
>> +
>> +static int dmard06_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan,
>> + int *val, int *val2, long mask)
>> +{
>> + struct dmard06_data *dmard06 = iio_priv(indio_dev);
>> + u8 buf;
>> + bool reversed;
>> + int error;
>> + int tmp;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_RAW:
>> + error = dmard06_i2c_read(dmard06->client, chan->address, &buf);
>> + if (error) {
>> + dev_err(&dmard06->client->dev,
>> + "Failed to read data %d\n", error);
>> + return error;
>> + }
>> +
>> + reversed = (buf >> 7) & 1;
>> + tmp = (int)((buf & 0x7f) >> 1);
>
>
>> +
>> + switch (chan->type) {
>> + case IIO_ACCEL:
>
> wouldn't sign_extend32(buf >> 1, 6) do the job?
>
>> + *val = reversed ? (tmp - DMARD06_AXIS_MAX_VAL) : tmp;
>> + return IIO_VAL_INT;
>> + case IIO_TEMP:
>> + *val = reversed ? -tmp : tmp;
>> + return IIO_VAL_INT;
>> + default:
>> + return -EINVAL;
>> + }
>> + case IIO_CHAN_INFO_OFFSET:
>> + switch (chan->type) {
>> + case IIO_TEMP:
>> + *val = DMARD06_TEMP_CENTER_VAL;
>> + return IIO_VAL_INT;
>> + default:
>> + return -EINVAL;
>> + }
>> + case IIO_CHAN_INFO_SCALE:
>> + switch (chan->type) {
>> + case IIO_ACCEL:
>> + *val = 0;
>> + *val2 = DMARD06_AXIS_SCALE_VAL;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + default:
>> + return -EINVAL;
>> + }
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> +static const struct iio_info dmard06_info = {
>> + .driver_module = THIS_MODULE,
>> + .read_raw = dmard06_read_raw,
>> +};
>> +
>> +#define DMARD06_ACCEL_CHANNEL(_axis, reg) { \
>
> maybe rename reg to _reg
>
>> + .type = IIO_ACCEL, \
>> + .address = reg, \
>> + .channel2 = IIO_MOD_##_axis, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>> + .modified = 1, \
>> +}
>> +
>> +#define DMARD06_TEMP_CHANNEL(reg) { \
>> + .type = IIO_TEMP, \
>> + .address = reg, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>> + BIT(IIO_CHAN_INFO_OFFSET), \
>> +}
>> +
>> +static const struct iio_chan_spec dmard06_channels[] = {
>> + DMARD06_ACCEL_CHANNEL(X, DMARD06_XOUT_REG),
>> + DMARD06_ACCEL_CHANNEL(Y, DMARD06_YOUT_REG),
>> + DMARD06_ACCEL_CHANNEL(Z, DMARD06_ZOUT_REG),
>> + DMARD06_TEMP_CHANNEL(DMARD06_TOUT_REG),
>> +};
>> +
>> +static int dmard06_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + int error;
>> + struct iio_dev *indio_dev;
>> + struct dmard06_data *dmard06;
>> +
>> + dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
>
> not needed
>
>> +
>> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
>> + dev_err(&client->dev, "I2C check functionality failed\n");
>> + return -ENXIO;
>> + }
>> +
>> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dmard06));
>> + if (!indio_dev) {
>> + dev_err(&client->dev, "Failed to allocate iio device\n");
>> + return -ENOMEM;
>> + }
>> +
>> + dmard06 = iio_priv(indio_dev);
>> + dmard06->client = client;
>> +
>> + error = dmard06_read_chip_id(dmard06);
>> + if (error)
>> + return error;
>> +
>> + i2c_set_clientdata(client, indio_dev);
>> + indio_dev->dev.parent = &client->dev;
>> + indio_dev->name = DMARD06_DRV_NAME;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + indio_dev->channels = dmard06_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(dmard06_channels);
>> + indio_dev->info = &dmard06_info;
>> +
>> + return devm_iio_device_register(&client->dev, indio_dev);
>> +}
>> +
>> +static const struct i2c_device_id dmard06_id[] = {
>> + { "dmard06", 0 },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, dmard06_id);
>> +
>> +static const struct of_device_id dmard06_of_match[] = {
>> + { .compatible = "domintech,dmard06" },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(of, dmard06_of_match);
>> +
>> +static struct i2c_driver dmard06_driver = {
>> + .probe = dmard06_probe,
>> + .id_table = dmard06_id,
>> + .driver = {
>> + .name = DMARD06_DRV_NAME,
>> + .of_match_table = of_match_ptr(dmard06_of_match),
>> + },
>> +};
>> +module_i2c_driver(dmard06_driver);
>> +
>> +MODULE_AUTHOR("Aleksei Mamlin <mamlinav@gmail.com>");
>> +MODULE_DESCRIPTION("Domintech DMARD06 accelerometer driver");
>> +MODULE_LICENSE("GPL v2");
>>
>