Re: [PATCH 4/4] iio: accel: Add driver for the MiraMEMS DA280 3-axis 14-bit digital accelerometer

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On 08/10/16 19:02, Hans de Goede wrote:
> Hi,
> 
> On 08-10-16 19:17, Jonathan Cameron wrote:
>> On 08/10/16 13:34, Hans de Goede wrote:
>>> Add an iio driver for the MiraMEMS DA280 3-axis 14-bit accelerometer, as
>>> well as for the DA226 which is a fully compatible 2-axis version.
>>>
>>> Datasheets for the DA280 and DA226 can be found at the manufacturers site:
>>> http://www.miramems.com/en/products.asp?list=1
>>>
>>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>> How many more of these devices do you have? :)
> 
> I own 13 identical (on the outside) 7" android tablets with an
> Allwinner A13/A23/A33 SoC, and I've access to 3 friends of mine own.
> 
> And I'm trying to run Fedora with the mainline kernel on all 16 of them.
> I'm actually working on hardware auto-detection for devicetree to deal
> with the internal differences these "identical" tablets have, see:
> 
> https://openiotelceurope2016.sched.org/event/7rqw/devicetree-hardware-autoconfiguration-hans-de-goede-red-hat?iframe=no&w=i:100;&sidebar=yes&bg=no
> 
> I've the accelerometer working on all of them (now), so this should
> be my last patch for a while. Although I do plan to add orientation
> support to all the accel drivers used in those tablets, so I
> guess that will be another round of patches.
> 
>> You have another unwanted le16_to_cpu conversion of data coming off
>> the back of an smbus word read.
> 
> Ugh, I distinctly remember thinking that I needed to take that
> out in this driver too, but clearly I did not. I'll post a fixed
> v2 soon.
Meh, happens to us all :)
> 
>> Otherwise, looks good to me.
> 
> Thank you for the quick response and review. I must say I find
> the iio subsys a very welcoming subsys to contribute too.
It is indeed a nice corner of the kernel to work in.  If it
wasn't I'd have burnt out long ago!

Stuff like Daniel and co + now Alison mentoring outreachy
certainly helps + a steady stream of other people just getting
started keeps a level of enthusiasm going.  Might help that generally
the parts are cheap and getting something going as you've seen
is simple + we are in the classic (advanced) maker territory.

Anyhow, I thoroughly agree and would just like to add thanks
to everyone who does review - I wouldn't keep up (anywhere near)
without you all!

Anyhow enough soppy stuff - back to reviewing ;)

Jonathan
> 
> Regards,
> 
> Hans
> 
> 
>>
>> Jonathan
>>> ---
>>>  .../devicetree/bindings/i2c/trivial-devices.txt    |   2 +
>>>  drivers/iio/accel/Kconfig                          |  10 ++
>>>  drivers/iio/accel/Makefile                         |   1 +
>>>  drivers/iio/accel/da280.c                          | 183 +++++++++++++++++++++
>>>  4 files changed, 196 insertions(+)
>>>  create mode 100644 drivers/iio/accel/da280.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
>>> index b23ded3..6e4ba81 100644
>>> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
>>> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
>>> @@ -124,6 +124,8 @@ microchip,mcp4662-502    Microchip 8-bit Dual I2C Digital Potentiometer with NV Mem
>>>  microchip,mcp4662-103    Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k)
>>>  microchip,mcp4662-503    Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k)
>>>  microchip,mcp4662-104    Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k)
>>> +miramems,da226        MiraMEMS DA226 2-axis 14-bit digital accelerometer
>>> +miramems,da280        MiraMEMS DA280 3-axis 14-bit digital accelerometer
>>>  miramems,da311        MiraMEMS DA311 3-axis 12-bit digital accelerometer
>>>  national,lm63        Temperature sensor with integrated fan control
>>>  national,lm75        I2C TEMP SENSOR
>>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>>> index c94348f..c2ed6cf 100644
>>> --- a/drivers/iio/accel/Kconfig
>>> +++ b/drivers/iio/accel/Kconfig
>>> @@ -52,6 +52,16 @@ config BMC150_ACCEL_SPI
>>>      tristate
>>>      select REGMAP_SPI
>>>
>>> +config DA280
>>> +    tristate "MiraMEMS DA280 3-axis 14-bit digital accelerometer driver"
>>> +    depends on I2C
>>> +    help
>>> +      Say yes here to build support for the MiraMEMS DA280 3-axis 14-bit
>>> +      digital accelerometer.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called da280.
>>> +
>>>  config DA311
>>>      tristate "MiraMEMS DA311 3-axis 12-bit digital accelerometer driver"
>>>      depends on I2C
>>> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
>>> index 601ca59..b7a9ba7 100644
>>> --- a/drivers/iio/accel/Makefile
>>> +++ b/drivers/iio/accel/Makefile
>>> @@ -8,6 +8,7 @@ obj-$(CONFIG_BMA220) += bma220_spi.o
>>>  obj-$(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-$(CONFIG_DA280)    += da280.o
>>>  obj-$(CONFIG_DA311)    += da311.o
>>>  obj-$(CONFIG_DMARD06)    += dmard06.o
>>>  obj-$(CONFIG_DMARD09)    += dmard09.o
>>> diff --git a/drivers/iio/accel/da280.c b/drivers/iio/accel/da280.c
>>> new file mode 100644
>>> index 0000000..7b1fe88
>>> --- /dev/null
>>> +++ b/drivers/iio/accel/da280.c
>>> @@ -0,0 +1,183 @@
>>> +/**
>>> + * IIO driver for the MiraMEMS DA280 3-axis accelerometer and
>>> + * IIO driver for the MiraMEMS DA226 2-axis accelerometer
>>> + *
>>> + * Copyright (c) 2016 Hans de Goede <hdegoede@xxxxxxxxxx>
>>> + *
>>> + * 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>
>>> +#include <linux/iio/sysfs.h>
>>> +#include <linux/byteorder/generic.h>
>>> +
>>> +#define DA280_REG_CHIP_ID        0x01
>>> +#define DA280_REG_ACC_X_LSB        0x02
>>> +#define DA280_REG_ACC_Y_LSB        0x04
>>> +#define DA280_REG_ACC_Z_LSB        0x06
>>> +#define DA280_REG_MODE_BW        0x11
>>> +
>>> +#define DA280_CHIP_ID            0x13
>>> +#define DA280_MODE_ENABLE        0x1e
>>> +#define DA280_MODE_DISABLE        0x9e
>>> +
>>> +enum { da226, da280 };
>>> +
>>> +/*
>>> + * a value of + or -4096 corresponds to + or - 1G
>>> + * scale = 9.81 / 4096 = 0.002395019
>>> + */
>>> +
>>> +static const int da280_nscale = 2395019;
>>> +
>>> +#define DA280_CHANNEL(reg, axis) {    \
>>> +    .type = IIO_ACCEL,    \
>>> +    .address = reg,    \
>>> +    .modified = 1,    \
>>> +    .channel2 = IIO_MOD_##axis,    \
>>> +    .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),    \
>>> +    .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),    \
>>> +}
>>> +
>>> +static const struct iio_chan_spec da280_channels[] = {
>>> +    DA280_CHANNEL(DA280_REG_ACC_X_LSB, X),
>>> +    DA280_CHANNEL(DA280_REG_ACC_Y_LSB, Y),
>>> +    DA280_CHANNEL(DA280_REG_ACC_Z_LSB, Z),
>>> +};
>>> +
>>> +struct da280_data {
>>> +    struct i2c_client *client;
>>> +};
>>> +
>>> +static int da280_enable(struct i2c_client *client, bool enable)
>>> +{
>>> +    u8 data = enable ? DA280_MODE_ENABLE : DA280_MODE_DISABLE;
>>> +
>>> +    return i2c_smbus_write_byte_data(client, DA280_REG_MODE_BW, data);
>>> +}
>>> +
>>> +static int da280_read_raw(struct iio_dev *indio_dev,
>>> +                struct iio_chan_spec const *chan,
>>> +                int *val, int *val2, long mask)
>>> +{
>>> +    struct da280_data *data = iio_priv(indio_dev);
>>> +    int ret;
>>> +
>>> +    switch (mask) {
>>> +    case IIO_CHAN_INFO_RAW:
>>> +        ret = i2c_smbus_read_word_data(data->client, chan->address);
>>> +        if (ret < 0)
>>> +            return ret;
>>> +        /*
>>> +         * Values are 14 bits, stored as 16 bits with the 2
>>> +         * least significant bits always 0.
>>> +         */
>>> +        *val = ((short)le16_to_cpu(ret)) >> 2;
>> Same thing Lars picked up on before I think...  It's already in cpu endian.
>>
>>> +        return IIO_VAL_INT;
>>> +    case IIO_CHAN_INFO_SCALE:
>>> +        *val = 0;
>>> +        *val2 = da280_nscale;
>>> +        return IIO_VAL_INT_PLUS_NANO;
>>> +    default:
>>> +        return -EINVAL;
>>> +    }
>>> +}
>>> +
>>> +static const struct iio_info da280_info = {
>>> +    .driver_module    = THIS_MODULE,
>>> +    .read_raw    = da280_read_raw,
>>> +};
>>> +
>>> +static int da280_probe(struct i2c_client *client,
>>> +            const struct i2c_device_id *id)
>>> +{
>>> +    int ret;
>>> +    struct iio_dev *indio_dev;
>>> +    struct da280_data *data;
>>> +
>>> +    ret = i2c_smbus_read_byte_data(client, DA280_REG_CHIP_ID);
>>> +    if (ret != DA280_CHIP_ID)
>>> +        return (ret < 0) ? ret : -ENODEV;
>>> +
>>> +    indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>> +    if (!indio_dev)
>>> +        return -ENOMEM;
>>> +
>>> +    data = iio_priv(indio_dev);
>>> +    data->client = client;
>>> +    i2c_set_clientdata(client, indio_dev);
>>> +
>>> +    indio_dev->dev.parent = &client->dev;
>>> +    indio_dev->info = &da280_info;
>>> +    indio_dev->modes = INDIO_DIRECT_MODE;
>>> +    indio_dev->channels = da280_channels;
>>> +    if (id->driver_data == da226) {
>>> +        indio_dev->name = "da226";
>>> +        indio_dev->num_channels = 2;
>>> +    } else {
>>> +        indio_dev->name = "da280";
>>> +        indio_dev->num_channels = 3;
>>> +    }
>>> +
>>> +    ret = da280_enable(client, true);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    ret = iio_device_register(indio_dev);
>>> +    if (ret < 0) {
>>> +        dev_err(&client->dev, "device_register failed\n");
>>> +        da280_enable(client, false);
>>> +    }
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int da280_remove(struct i2c_client *client)
>>> +{
>>> +    struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>> +
>>> +    iio_device_unregister(indio_dev);
>>> +
>>> +    return da280_enable(client, false);
>>> +}
>>> +
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int da280_suspend(struct device *dev)
>>> +{
>>> +    return da280_enable(to_i2c_client(dev), false);
>>> +}
>>> +
>>> +static int da280_resume(struct device *dev)
>>> +{
>>> +    return da280_enable(to_i2c_client(dev), true);
>>> +}
>>> +#endif
>>> +
>>> +static SIMPLE_DEV_PM_OPS(da280_pm_ops, da280_suspend, da280_resume);
>>> +
>>> +static const struct i2c_device_id da280_i2c_id[] = {
>>> +    { "da226", da226 },
>>> +    { "da280", da280 },
>>> +    {}
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, da280_i2c_id);
>>> +
>>> +static struct i2c_driver da280_driver = {
>>> +    .driver = {
>>> +        .name = "da280",
>>> +        .pm = &da280_pm_ops,
>>> +    },
>>> +    .probe        = da280_probe,
>>> +    .remove        = da280_remove,
>>> +    .id_table    = da280_i2c_id,
>>> +};
>>> +
>>> +module_i2c_driver(da280_driver);
>>> +
>>> +MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
>>> +MODULE_DESCRIPTION("MiraMEMS DA280 3-Axis Accelerometer driver");
>>> +MODULE_LICENSE("GPL v2");
>>>
>>

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