Re: [PATCH v1 4/4] iio: imu: inv_mpu6050: Add SPI support for MPU6000

[Adriana Reus <adriana.reus@intel.com>]

Hi Lucas, Ge,


Thanks for pointing that out Lucas, I'm looking into it.

Ge, would it suffice to set the I2C_IF_DIS via an SPI transaction 
(spi_write or regmap_write)?
Couldn't the chip get confused during that transaction also?


On 03.02.2016 08:42, Ge Gao wrote:
> That is a good point.  That register should be set in case chip get confused if the spi signal mimic a I2C signal
>
> Ge
>
>> On Feb 2, 2016, at 10:31 PM, Lucas De Marchi <lucas.de.marchi@gmail.com> wrote:
>>
>> Hi Adriana,
>>
>>> On Tue, Feb 2, 2016 at 1:02 PM, Adriana Reus <adriana.reus@intel.com> wrote:
>>> The only difference between the MPU6000 and the
>>> MPU6050 is that the first also supports SPI.
>>> Add SPI driver for this chip.
>>>
>>> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
>>> ---
>>> Changes since initial version:
>>> * Modified Kconfig so that the SPI component selects the core component
>>>    instead of the other way around.
>>>
>>> drivers/iio/imu/inv_mpu6050/Kconfig       |  7 +++
>>> drivers/iio/imu/inv_mpu6050/Makefile      |  3 ++
>>> drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h |  1 +
>>> drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c | 80 +++++++++++++++++++++++++++++++
>>> 4 files changed, 91 insertions(+)
>>> create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c
>>>
>>> diff --git a/drivers/iio/imu/inv_mpu6050/Kconfig b/drivers/iio/imu/inv_mpu6050/Kconfig
>>> index 483f52d..6f6a419 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/Kconfig
>>> +++ b/drivers/iio/imu/inv_mpu6050/Kconfig
>>> @@ -25,3 +25,10 @@ config INV_MPU6050_I2C
>>>           This driver can be built as a module. The module will be called
>>>           inv-mpu6050-i2c.
>>>
>>> +config INV_MPU6050_SPI
>>> +       tristate "Invensense MPU6050 devices"
>>> +       select INV_MPU6050_IIO
>>> +       select REGMAP_SPI
>>> +       help
>>> +         This driver can be built as a module. The module will be called
>>> +         inv-mpu6050-spi.
>>> diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
>>> index ca4941d..734af5e 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/Makefile
>>> +++ b/drivers/iio/imu/inv_mpu6050/Makefile
>>> @@ -7,3 +7,6 @@ inv-mpu6050-objs := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o
>>>
>>> obj-$(CONFIG_INV_MPU6050_I2C) += inv-mpu6050-i2c.o
>>> inv-mpu6050-i2c-objs := inv_mpu_i2c.o inv_mpu_acpi.o
>>> +
>>> +obj-$(CONFIG_INV_MPU6050_SPI) += inv-mpu6050-spi.o
>>> +inv-mpu6050-spi-objs := inv_mpu_spi.o
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> index af406a3..758fe2b 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> @@ -62,6 +62,7 @@ struct inv_mpu6050_reg_map {
>>> enum inv_devices {
>>>         INV_MPU6050,
>>>         INV_MPU6500,
>>> +       INV_MPU6000,
>>>         INV_NUM_PARTS
>>> };
>>>
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c
>>> new file mode 100644
>>> index 0000000..484171e
>>> --- /dev/null
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c
>>> @@ -0,0 +1,80 @@
>>> +/*
>>> +* Copyright (C) 2015 Intel Corporation Inc.
>>> +*
>>> +* This software is licensed under the terms of the GNU General Public
>>> +* License version 2, as published by the Free Software Foundation, and
>>> +* may be copied, distributed, and modified under those terms.
>>> +*
>>> +* This program is distributed in the hope that it will be useful,
>>> +* but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> +* GNU General Public License for more details.
>>> +*/
>>> +#include <linux/module.h>
>>> +#include <linux/acpi.h>
>>> +#include <linux/spi/spi.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/iio/iio.h>
>>> +#include "inv_mpu_iio.h"
>>> +
>>> +static const struct regmap_config inv_mpu_regmap_config = {
>>> +       .reg_bits = 8,
>>> +       .val_bits = 8,
>>> +};
>>> +
>>> +static int inv_mpu_probe(struct spi_device *spi)
>>> +{
>>> +       struct regmap *regmap;
>>> +       const struct spi_device_id *id = spi_get_device_id(spi);
>>> +       const char *name = id ? id->name : NULL;
>>> +
>>> +       regmap = devm_regmap_init_spi(spi, &inv_mpu_regmap_config);
>>> +       if (IS_ERR(regmap)) {
>>> +               dev_err(&spi->dev, "Failed to register spi regmap %d\n",
>>> +                       (int)PTR_ERR(regmap));
>>> +               return PTR_ERR(regmap);
>>> +       }
>>> +
>>> +       return inv_mpu_core_probe(regmap, spi->irq, name);
>>
>> I think there's still some spi-only initialization missing. As per
>> datasheet we should disable the I2C interface when using the SPI
>> interface.
>>
>> Lucas De Marchi