[PATCH] aiodev: add ST L3GD20 Gyroscope and temperature sensor support

[Sascha Hauer]

On Fri, Jul 08, 2022 at 07:55:26AM +0200, Ahmad Fatoum wrote:
> The L3GD0 is an on-board peripheral of the STM32F429-DISCOVERY and as
> such a good target to test out SPI driver support. Add a simple aiodev
> driver to interface with it. It can read the chip's angular rate in
> three dimensions as well as the temperature sensor embedded in it.
> 
> Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
> ---
>  drivers/aiodev/Kconfig   |   6 ++
>  drivers/aiodev/Makefile  |   1 +
>  drivers/aiodev/st_gyro.c | 122 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 129 insertions(+)
>  create mode 100644 drivers/aiodev/st_gyro.c

Applied, thanks

Sascha

> 
> diff --git a/drivers/aiodev/Kconfig b/drivers/aiodev/Kconfig
> index 88a3b9a3431c..6bd697702ecf 100644
> --- a/drivers/aiodev/Kconfig
> +++ b/drivers/aiodev/Kconfig
> @@ -30,6 +30,12 @@ config LM75
>  	help
>  	  Support for LM75 and similar devices
>  
> +config ST_GYRO
> +	tristate "ST L3GD20 SPI gyro driver"
> +	depends on SPI
> +	help
> +	  Support for L3GD20 three-axis angular rate sensor.
> +
>  config MC13XXX_ADC
>  	tristate "MC13XXX ADC driver"
>  	depends on MFD_MC13XXX
> diff --git a/drivers/aiodev/Makefile b/drivers/aiodev/Makefile
> index 4c92a403a293..06a63b0d2d78 100644
> --- a/drivers/aiodev/Makefile
> +++ b/drivers/aiodev/Makefile
> @@ -3,6 +3,7 @@
>  obj-$(CONFIG_AIODEV) += core.o
>  obj-$(CONFIG_IMX_THERMAL) += imx_thermal.o
>  obj-$(CONFIG_LM75) += lm75.o
> +obj-$(CONFIG_ST_GYRO) += st_gyro.o
>  obj-$(CONFIG_MC13XXX_ADC) += mc13xxx_adc.o
>  obj-$(CONFIG_QORIQ_THERMAL) += qoriq_thermal.o
>  obj-$(CONFIG_AM335X_ADC) += am335x_adc.o
> diff --git a/drivers/aiodev/st_gyro.c b/drivers/aiodev/st_gyro.c
> new file mode 100644
> index 000000000000..3938d8239e4b
> --- /dev/null
> +++ b/drivers/aiodev/st_gyro.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// SPDX-FileCopyrightText: 2022 Ahmad Fatoum
> +
> +#include <common.h>
> +#include <driver.h>
> +#include <xfuncs.h>
> +#include <spi/spi.h>
> +#include <aiodev.h>
> +
> +#define ST_GYRO_WHO_AM_I    0x0F
> +#define ST_GYRO_CTRL_REG1   0x20
> +
> +#define ST_GYRO_DEFAULT_OUT_TEMP_ADDR           0x26
> +#define ST_GYRO_DEFAULT_OUT_X_L_ADDR            0x28
> +#define ST_GYRO_DEFAULT_OUT_Y_L_ADDR            0x2a
> +#define ST_GYRO_DEFAULT_OUT_Z_L_ADDR            0x2c
> +
> +#define ST_GYRO_OUT_L_ADDR(idx)		\
> +	(ST_GYRO_DEFAULT_OUT_X_L_ADDR + 2 * (idx))
> +
> +#define ST_GYRO_OUT_H_ADDR(idx)		\
> +	(ST_GYRO_OUT_L_ADDR(idx) + 1)
> +
> +#define ST_GYRO_READ		0x80
> +#define ST_GYRO_WRITE		0x00
> +#define ST_GYRO_MULTI		0x40
> +
> +struct st_gyro {
> +	struct aiodevice aiodev;
> +	struct aiochannel aiochan[4];
> +	struct spi_device *spi;
> +};
> +#define to_st_gyro(chan) container_of(chan->aiodev, struct st_gyro, aiodev)
> +
> +static int st_gyro_read(struct aiochannel *chan, int *val)
> +{
> +	struct st_gyro *gyro = to_st_gyro(chan);
> +	int ret;
> +	u8 tx;
> +	u8 rx_h, rx_l;
> +
> +	if (chan->index == 3) {
> +		tx = ST_GYRO_DEFAULT_OUT_TEMP_ADDR | ST_GYRO_READ;
> +		ret = spi_write_then_read(gyro->spi, &tx, 1, &rx_l, 1);
> +		if (ret)
> +			return ret;
> +
> +		*val = (s8)rx_l;
> +		return 0;
> +	}
> +
> +	tx = ST_GYRO_OUT_H_ADDR(chan->index) | ST_GYRO_READ;
> +	ret = spi_write_then_read(gyro->spi, &tx, 1, &rx_h, 1);
> +	if (ret)
> +		return ret;
> +
> +	tx = ST_GYRO_OUT_L_ADDR(chan->index) | ST_GYRO_READ;
> +	ret = spi_write_then_read(gyro->spi, &tx, 1, &rx_l, 1);
> +	if (ret)
> +		return ret;
> +
> +	*val = (s16)((rx_h << 8) | rx_l);
> +	*val *= 250;
> +	*val >>= 16;
> +
> +	return 0;
> +}
> +
> +static int st_gyro_probe(struct device_d *dev)
> +{
> +	u8 tx[2], rx[2];
> +	struct st_gyro *gyro;
> +	int ret, i;
> +
> +	gyro = xzalloc(sizeof(*gyro));
> +	gyro->spi = to_spi_device(dev);
> +
> +	tx[0] = ST_GYRO_WHO_AM_I | ST_GYRO_READ;
> +	ret = spi_write_then_read(gyro->spi, tx, 1, rx, 1);
> +	if (ret)
> +		return -EIO;
> +	if (rx[0] != 0xD4)
> +		return dev_err_probe(dev, -ENODEV, "unexpected device WAI: %02x\n", rx[0]);
> +
> +	/* initialize device */
> +	tx[0] = ST_GYRO_CTRL_REG1 | ST_GYRO_WRITE;
> +	tx[1] = 0xF; /* normal mode, 3 channels */
> +	ret = spi_write(gyro->spi, tx, 2);
> +	if (ret)
> +		return -EIO;
> +
> +	gyro->aiodev.num_channels = 4;
> +	gyro->aiodev.hwdev = dev;
> +	gyro->aiodev.read = st_gyro_read;
> +	gyro->aiodev.name = "gyroscope";
> +	gyro->aiodev.channels =
> +		xmalloc(gyro->aiodev.num_channels *
> +			sizeof(gyro->aiodev.channels[0]));
> +	for (i = 0; i < 3; i++) {
> +		gyro->aiodev.channels[i] = &gyro->aiochan[i];
> +		gyro->aiochan[i].unit = "dps";
> +		gyro->aiochan[i].index = i;
> +	}
> +
> +	gyro->aiodev.channels[3] = &gyro->aiochan[3];
> +	gyro->aiochan[3].unit = "C";
> +	gyro->aiochan[3].index = 3;
> +
> +	return aiodevice_register(&gyro->aiodev);
> +}
> +
> +static const struct of_device_id st_gyro_match[] = {
> +	{ .compatible = "st,l3gd20-gyro"  },
> +	{ /* sentinel */ }
> +};
> +
> +static struct driver_d st_gyro_driver = {
> +	.name  = "st_gyro",
> +	.probe = st_gyro_probe,
> +	.of_compatible = st_gyro_match,
> +};
> +device_spi_driver(st_gyro_driver);
> -- 
> 2.34.1
> 
> 
> 

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