Hi Adriana,
On Thu, Feb 4, 2016 at 7:20 AM, Adriana Reus <adriana.reus@xxxxxxxxx> 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@xxxxxxxxx>
> ---
[ ... ]
> 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..6a1de35
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_spi.c
> @@ -0,0 +1,87 @@
> +/*
> +* 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;
> + int result;
> +
> + 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);
> + }
> +
> + result = regmap_write(regmap, INV_MPU6050_REG_USER_CTRL,
> + INV_MPU6050_BIT_I2C_IF_DIS);
> + if (result) {
> + dev_err(&spi->dev, "Failed to disable I2C interface\n");
> + return result;
> + }
> +
> + return inv_mpu_core_probe(regmap, spi->irq, name);
Here we reset the chip making superfluous the I2C disable above. See
note on section "9.1 I2C and SPI (MPU-6000 only) Serial Interfaces":
"To prevent switching into I 2 C mode when using SPI (MPU-6000), the I
2 C interface should be disabled by
setting the I2C_IF_DIS configuration bit. Setting this bit should be
performed immediately after waiting for the
time specified by the “Start-Up Time for Register Read/Write” in Section 6.3."
Lucas De Marchi
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