diff mbox series

[v2,5/7] iio: imu: inv_mpu6050: helpers for using i2c master on auxiliary bus

Message ID 20190912105804.15650-5-jmaneyrol@invensense.com (mailing list archive)
State New, archived
Headers show
Series add magnetometer support for MPU925x | expand

Commit Message

Jean-Baptiste Maneyrol Sept. 12, 2019, 10:58 a.m. UTC 
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>
---
 drivers/iio/imu/inv_mpu6050/Makefile      |   3 +-
 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c | 184 ++++++++++++++++++++++
 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h |  46 ++++++
 3 files changed, 232 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
 create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h

Comments

Jonathan Cameron Sept. 15, 2019, 1:13 p.m. UTC | #1 
On Thu, 12 Sep 2019 10:58:34 +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>
Docs should be by the implementation not in the header.

Otherwise, this looks fine I think. I'm not planning to plough through
datasheets for this set so mostly assuming you got it right ;)

Jonathan



> ---
>  drivers/iio/imu/inv_mpu6050/Makefile      |   3 +-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c | 184 ++++++++++++++++++++++
>  drivers/iio/imu/inv_mpu6050/inv_mpu_aux.h |  46 ++++++
>  3 files changed, 232 insertions(+), 1 deletion(-)
>  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..2cfbd926522f 100644
> --- a/drivers/iio/imu/inv_mpu6050/Makefile
> +++ b/drivers/iio/imu/inv_mpu6050/Makefile
> @@ -4,7 +4,8 @@
>  #
>  
>  obj-$(CONFIG_INV_MPU6050_IIO) += inv-mpu6050.o
> -inv-mpu6050-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o
> +inv-mpu6050-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o \
> +		 inv_mpu_aux.o
>  
>  obj-$(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..b4907c1a8bb6
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
> @@ -0,0 +1,184 @@
> +// 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;
> +	return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val);
> +}
> +
> +/*
> + * 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 */
> +	return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
> +				val, size);
> +
> +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.

Documentation at implementation, not in the header.
Tends to rot when hidden away from the code.

> + */
> +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_ */
diff mbox series

Patch

diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
index 33bec09fee9b..2cfbd926522f 100644
--- a/drivers/iio/imu/inv_mpu6050/Makefile
+++ b/drivers/iio/imu/inv_mpu6050/Makefile
@@ -4,7 +4,8 @@ 
 #
 
 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-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o \
+		 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..b4907c1a8bb6
--- /dev/null
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_aux.c
@@ -0,0 +1,184 @@ 
+// 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;
+	return regmap_write(st->map, INV_MPU6050_REG_I2C_MST_DELAY_CTRL, val);
+}
+
+/*
+ * 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 */
+	return regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
+				val, size);
+
+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_ */