Re: [PATCH 8/9 v2] iio: pressure: bmp280: add support for BMP085 EOC interrupt

[Jonathan Cameron <jic23@kernel.org>]

On 22/06/16 21:53, Linus Walleij wrote:
> The first version of this sensor, BMP085, supports sending an
> End-of-Conversion (EOC) interrupt. Add code to support this using
> a completion, in a similar vein as drivers/misc/bmp085.c does.
> 
> Make sure to check that we are given a rising edge, because the
> EOC line goes from low-to-high when the conversion is ready.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Rather obvious race condition in probe..
> ---
> ChangeLog v1->v2:
> - Fix spelling mistakes
> ---
>  drivers/iio/pressure/bmp280-core.c | 83 ++++++++++++++++++++++++++++++++++----
>  drivers/iio/pressure/bmp280-i2c.c  |  3 +-
>  drivers/iio/pressure/bmp280-spi.c  |  3 +-
>  drivers/iio/pressure/bmp280.h      |  3 +-
>  4 files changed, 81 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index 733ef3c08102..7b2a03d6fd1d 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -26,6 +26,9 @@
>  #include <linux/iio/sysfs.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h> /* For irq_get_irq_data() */
> +#include <linux/completion.h>
>  
>  #include "bmp280.h"
>  
> @@ -33,6 +36,8 @@ struct bmp280_data {
>  	struct device *dev;
>  	struct mutex lock;
>  	struct regmap *regmap;
> +	struct completion done;
> +	bool use_eoc;
>  	const struct bmp280_chip_info *chip_info;
>  	struct regulator *vddd;
>  	struct regulator *vdda;
> @@ -593,16 +598,32 @@ static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
>  	unsigned int delay_us;
>  	unsigned int ctrl;
>  
> +	if (data->use_eoc)
> +		init_completion(&data->done);
> +
>  	ret = regmap_write(data->regmap, BMP280_REG_CTRL_MEAS, ctrl_meas);
>  	if (ret)
>  		return ret;
>  
> -	if (ctrl_meas == BMP180_MEAS_TEMP)
> -		delay_us = 4500;
> -	else
> -		delay_us = conversion_time_max[data->oversampling_press];
> -
> -	usleep_range(delay_us, delay_us + 1000);
> +	if (data->use_eoc) {
> +		/*
> +		 * If we have a completion interrupt, use it, wait up to
> +		 * 100ms. The longest conversion time listed is 76.5 ms for
> +		 * advanced resolution mode.
> +		 */
> +		ret = wait_for_completion_timeout(&data->done,
> +						  1 + msecs_to_jiffies(100));
> +		if (!ret)
> +			dev_err(data->dev, "timeout waiting for completion\n");
> +	} else {
> +		if (ctrl_meas == BMP180_MEAS_TEMP)
> +			delay_us = 4500;
> +		else
> +			delay_us =
> +				conversion_time_max[data->oversampling_press];
> +
> +		usleep_range(delay_us, delay_us + 1000);
> +	}
>  
>  	ret = regmap_read(data->regmap, BMP280_REG_CTRL_MEAS, &ctrl);
>  	if (ret)
> @@ -844,16 +865,28 @@ static const struct bmp280_chip_info bmp180_chip_info = {
>  	.read_press = bmp180_read_press,
>  };
>  
> +static irqreturn_t bmp058_eoc_irq(int irq, void *d)
> +{
> +	struct bmp280_data *data = d;
> +
> +	complete(&data->done);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +
>  int bmp280_common_probe(struct device *dev,
>  			struct regmap *regmap,
>  			unsigned int chip,
> -			const char *name)
> +			const char *name,
> +			int irq)
>  {
>  	int ret;
>  	struct iio_dev *indio_dev;
>  	struct bmp280_data *data;
>  	unsigned int chip_id;
>  	struct gpio_desc *gpiod;
> +	unsigned long irq_trig;
>  
>  	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
>  	if (!indio_dev)
> @@ -937,5 +970,39 @@ int bmp280_common_probe(struct device *dev,
>  	if (ret < 0)
>  		return ret;
>  
> -	return devm_iio_device_register(dev, indio_dev);
> +	ret = devm_iio_device_register(dev, indio_dev);
You just exposed the userspace interface here.... Yet (see below)
> +	if (ret) {
> +		dev_err(dev, "unable to register IIO device\n");
> +		return ret;
> +	}
> +
> +	/*
> +	 * Attempt to grab an optional EOC IRQ - only the BMP058 has this
> +	 * however as it happens, the BMP058 shares the chip ID of BMP180
> +	 * so we look for an IRQ if we have that.
> +	 */
> +	if (irq <= 0 || (chip_id  != BMP180_CHIP_ID))
> +		return 0;
> +
> +	irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
> +	if (irq_trig != IRQF_TRIGGER_RISING) {
> +		dev_err(dev, "non-rising trigger given for EOC interrupt, "
> +			"trying to enforce it\n");
> +		irq_trig = IRQF_TRIGGER_RISING;
> +	}
> +	ret = devm_request_threaded_irq(dev,
> +			irq,
> +			bmp058_eoc_irq,
> +			NULL,
> +			irq_trig,
> +			name,
> +			data);
> +	if (ret) {
> +		/* Bail out without IRQ but keep the driver in place */
> +		dev_err(dev, "unable to request DRDY IRQ\n");
> +		return 0;
> +	}
A necessary interrupt isn't available until here.  Please reorder.
The register call for userspace (and for that matter inkernel users) must
be made only one everything else is ready.

 
> +
> +	data->use_eoc = true;
> +	return 0;
>  }
> diff --git a/drivers/iio/pressure/bmp280-i2c.c b/drivers/iio/pressure/bmp280-i2c.c
> index a981670e5dc0..b9a2562e8a7e 100644
> --- a/drivers/iio/pressure/bmp280-i2c.c
> +++ b/drivers/iio/pressure/bmp280-i2c.c
> @@ -33,7 +33,8 @@ static int bmp280_i2c_probe(struct i2c_client *client,
>  	return bmp280_common_probe(&client->dev,
>  				   regmap,
>  				   id->driver_data,
> -				   id->name);
> +				   id->name,
> +				   client->irq);
>  }
>  
>  static const struct acpi_device_id bmp280_acpi_i2c_match[] = {
> diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-spi.c
> index 2b9955f48d58..05ddf2ee7519 100644
> --- a/drivers/iio/pressure/bmp280-spi.c
> +++ b/drivers/iio/pressure/bmp280-spi.c
> @@ -81,7 +81,8 @@ static int bmp280_spi_probe(struct spi_device *spi)
>  	return bmp280_common_probe(&spi->dev,
>  				   regmap,
>  				   id->driver_data,
> -				   id->name);
> +				   id->name,
> +				   spi->irq);
>  }
>  
>  static const struct of_device_id bmp280_of_spi_match[] = {
> diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
> index acb40de2f581..9dee048b5a74 100644
> --- a/drivers/iio/pressure/bmp280.h
> +++ b/drivers/iio/pressure/bmp280.h
> @@ -104,4 +104,5 @@ extern const struct regmap_config bmp280_regmap_config;
>  int bmp280_common_probe(struct device *dev,
>  			struct regmap *regmap,
>  			unsigned int chip,
> -			const char *name);
> +			const char *name,
> +			int irq);
>