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From: Jonathan Cameron <jic23@kernel.org>
To: Jean-Baptiste Maneyrol <JManeyrol@invensense.com>
Cc: "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Re: [PATCH 5/8] iio: imu: inv_mpu6050: helpers for using i2c master on auxiliary bus
Date: Sun, 8 Sep 2019 12:57:45 +0100	[thread overview]
Message-ID: <20190908125745.1c51785a@archlinux> (raw)
In-Reply-To: <20190829151801.13014-6-jmaneyrol@invensense.com>

On Thu, 29 Aug 2019 15:18:42 +0000
Jean-Baptiste Maneyrol <JManeyrol@invensense.com> wrote:

> Add helper functions to use the i2c auxiliary bus with the MPU i2c
> master block.
> 
> Support only register based chip, reading and 1 byte writing. These
> will be useful for initializing magnetometers inside MPU9x50 chips.
> 
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>

A few minor comments inline.

Always the fun question on whether we should support these sorts of
aux buses as true masters and register them as such, or whether it's
just not worth the effort as they are limited...

> ---
>  drivers/iio/imu/inv_mpu6050/Makefile      |   1 +
>  drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c | 191 ++++++++++++++++++++++
>  drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h |  46 ++++++
>  3 files changed, 238 insertions(+)
>  create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
>  create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
> index 33bec09fee9b..187f003c81f2 100644
> --- a/drivers/iio/imu/inv_mpu6050/Makefile
> +++ b/drivers/iio/imu/inv_mpu6050/Makefile
> @@ -5,6 +5,7 @@
>  
>  obj-$(CONFIG_INV_MPU6050_IIO) += inv-mpu6050.o
>  inv-mpu6050-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o
> +inv-mpu6050-$(CONFIG_INV_MPU6050_MAGN) += inv_mpu_aux.o
>  
>  obj-$(CONFIG_INV_MPU6050_I2C) += inv-mpu6050-i2c.o
>  inv-mpu6050-i2c-y := inv_mpu_i2c.o inv_mpu_acpi.o
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
> new file mode 100644
> index 000000000000..afb957567c12
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
> @@ -0,0 +1,191 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/regmap.h>
> +#include <linux/delay.h>
> +
> +#include "inv_mpu_iio.h"
> +
> +/*
> + * i2c master auxiliary bus transfer function.
> + * Requires the i2c operations to be correctly setup before.
> + */
> +static int inv_mpu_i2c_master_xfer(const struct inv_mpu6050_state *st)
> +{
> +	/* use 50hz frequency for xfer */
> +	const unsigned int freq = 50;
> +	const unsigned int period_ms = 1000 / freq;
> +	uint8_t d;
> +	unsigned int user_ctrl;
> +	int ret;
> +
> +	/* set sample rate */
> +	d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(freq);
> +	ret = regmap_write(st->map, st->reg->sample_rate_div, d);
> +	if (ret)
> +		return ret;
> +
> +	/* start i2c master */
> +	user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN;
> +	ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
> +	if (ret)
> +		goto error_restore_rate;
> +
> +	/* wait for xfer: 1 period + half-period margin */
> +	msleep(period_ms + period_ms / 2);
> +
> +	/* stop i2c master */
> +	user_ctrl = st->chip_config.user_ctrl;
> +	ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
> +	if (ret)
> +		goto error_stop_i2c;
> +
> +	/* restore sample rate */
> +	d = st->chip_config.divider;
> +	ret = regmap_write(st->map, st->reg->sample_rate_div, d);
> +	if (ret)
> +		goto error_restore_rate;
> +
> +	return 0;
> +
> +error_stop_i2c:
> +	regmap_write(st->map, st->reg->user_ctrl, st->chip_config.user_ctrl);
> +error_restore_rate:
> +	regmap_write(st->map, st->reg->sample_rate_div, st->chip_config.divider);
> +	return ret;
> +}
> +
> +int inv_mpu_aux_init(const struct inv_mpu6050_state *st)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	/* configure i2c master */
> +	val = INV_MPU6050_BITS_I2C_MST_CLK_400KHZ |
> +			INV_MPU6050_BIT_WAIT_FOR_ES;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_CTRL, val);
> +	if (ret)
> +		return ret;
> +
> +	/* configure i2c master delay */
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, 0);
> +	if (ret)
> +		return ret;
> +	val = INV_MPU6050_BIT_I2C_SLV0_DLY_EN |
> +			INV_MPU6050_BIT_I2C_SLV1_DLY_EN |
> +			INV_MPU6050_BIT_I2C_SLV2_DLY_EN |
> +			INV_MPU6050_BIT_I2C_SLV3_DLY_EN |
> +			INV_MPU6050_BIT_DELAY_ES_SHADOW;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val);

return regmap_write...

> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +/*
> + * i2c slave reading using SLV0
> + */
> +int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr,
> +		     uint8_t reg, uint8_t *val, size_t size)
> +{
> +	unsigned int status;
> +	int ret;
> +
> +	if (size > 0x0F)
> +		return -EINVAL;
> +
> +	/* setup i2c SLV0 control: i2c addr, register, enable + size */
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0),
> +			   INV_MPU6050_BIT_I2C_SLV_RNW | addr);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
> +			   INV_MPU6050_BIT_SLV_EN | size);
> +	if (ret)
> +		return ret;
> +
> +	/* do i2c xfer */
> +	ret = inv_mpu_i2c_master_xfer(st);
> +	if (ret)
> +		goto error_disable_i2c;
> +
> +	/* disable i2c slave */
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
> +	if (ret)
> +		goto error_disable_i2c;
> +
> +	/* check i2c status */
> +	ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
> +	if (ret)
> +		return ret;
> +	if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)
> +		return -EIO;
> +
> +	/* read data in registers */
> +	ret = regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
> +			       val, size);

return regmap_...

> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +
> +error_disable_i2c:
> +	regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
> +	return ret;
> +}
> +
> +/*
> + * i2c slave writing 1 byte using SLV0
> + */
> +int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr,
> +		      uint8_t reg, uint8_t val)
> +{
> +	unsigned int status;
> +	int ret;
> +
> +	/* setup i2c SLV0 control: i2c addr, register, value, enable + size */
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0), addr);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0), reg);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(0), val);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
> +			   INV_MPU6050_BIT_SLV_EN | 1);
> +	if (ret)
> +		return ret;
> +
> +	/* do i2c xfer */
> +	ret = inv_mpu_i2c_master_xfer(st);
> +	if (ret)
> +		goto error_disable_i2c;
> +
> +	/* disable i2c slave */
> +	ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
> +	if (ret)
> +		goto error_disable_i2c;
> +
> +	/* check i2c status */
> +	ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
> +	if (ret)
> +		return ret;
> +	if (status & INV_MPU6050_BIT_I2C_SLV0_NACK)
> +		return -EIO;
> +
> +	return 0;
> +
> +error_disable_i2c:
> +	regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0), 0);
> +	return ret;
> +}
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h
> new file mode 100644
> index 000000000000..bae4eab58e6c
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h
> @@ -0,0 +1,46 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#ifndef INV_MPU_AUX_H_
> +#define INV_MPU_AUX_H_
> +
> +#include <linux/kernel.h>
> +
> +#include "inv_mpu_iio.h"
> +
> +/**
> + * inv_mpu_aux_init() - init i2c auxiliary bus
> + * @st: driver internal state
> + *
> + * Returns 0 on success, a negative error code otherwise.
> + */
> +int inv_mpu_aux_init(const struct inv_mpu6050_state *st);
> +
> +/**
> + * inv_mpu_aux_read() - read register function for i2c auxiliary bus
> + * @st: driver internal state.
> + * @addr: chip i2c Address
> + * @reg: chip register address
> + * @val: buffer for storing read bytes
> + * @size: number of bytes to read
> + *
> + *  Returns 0 on success, a negative error code otherwise.
> + */
> +int inv_mpu_aux_read(const struct inv_mpu6050_state *st, uint8_t addr,
> +		     uint8_t reg, uint8_t *val, size_t size);
> +
> +/**
> + * inv_mpu_aux_write() - write register function for i2c auxiliary bus
> + * @st: driver internal state.
> + * @addr: chip i2c Address
> + * @reg: chip register address
> + * @val: 1 byte value to write
> + *
> + *  Returns 0 on success, a negative error code otherwise.
> + */
> +int inv_mpu_aux_write(const struct inv_mpu6050_state *st, uint8_t addr,
> +		      uint8_t reg, uint8_t val);
> +
> +#endif		/* INV_MPU_AUX_H_ */


  reply	other threads:[~2019-09-08 11:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-29 15:18 [PATCH 0/8] add magnetometer support for MPU925x Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 1/8] iio: imu: inv_mpu6050: disable i2c mux for 925x under Kconfig Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 2/8] iio: imu: inv_mpu6050: add header include protection macro Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 3/8] iio: imu: inv_mpu6050: add defines for supporting 9-axis chips Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 4/8] iio: imu: inv_mpu6050: fix objects syntax in Makefile Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 5/8] iio: imu: inv_mpu6050: helpers for using i2c master on auxiliary bus Jean-Baptiste Maneyrol
2019-09-08 11:57   ` Jonathan Cameron [this message]
2019-08-29 15:18 ` [PATCH 6/8] iio: imu: inv_mpu6050: add magnetometer implementation for MPU925x Jean-Baptiste Maneyrol
2019-09-08 11:57   ` Jonathan Cameron
2019-08-29 15:18 ` [PATCH 7/8] iio: imu: inv_mpu6050: add magnetometer support inside mpu driver Jean-Baptiste Maneyrol
2019-09-08 12:05   ` Jonathan Cameron
2019-09-09 16:18     ` Jean-Baptiste Maneyrol
2019-08-29 15:18 ` [PATCH 8/8] iio: imu: inv_mpu6050: add fifo support for magnetometer data Jean-Baptiste Maneyrol
2019-09-08 12:07   ` Jonathan Cameron
2019-09-08 11:42 ` [PATCH 0/8] add magnetometer support for MPU925x Jonathan Cameron
2019-09-09  9:55   ` Jean-Baptiste Maneyrol
2019-09-10 13:39     ` Jonathan Cameron

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