Re: [PATCH 6/8] iio: cleanup and move comments in hmc5843

[Jonathan Cameron <jic23@kernel.org>]

On 5/8/2012 11:20 PM, Peter Meerwald wrote:
> From: Peter Meerwald<p.meerwald@bct-electronic.com>
>
All sensible enough.  A few comments inline but I'm fine with what you 
have here.
> Signed-off-by: Peter Meerwald<pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
>   drivers/staging/iio/magnetometer/hmc5843.c |  122 ++++++++++++++-------------
>   1 files changed, 63 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/staging/iio/magnetometer/hmc5843.c b/drivers/staging/iio/magnetometer/hmc5843.c
> index 57ab4fb..57ed182 100644
> --- a/drivers/staging/iio/magnetometer/hmc5843.c
> +++ b/drivers/staging/iio/magnetometer/hmc5843.c
> @@ -103,6 +103,18 @@ static const int hmc5843_regval_to_nanoscale[] = {
>   	6173, 7692, 10309, 12821, 18868, 21739, 25641, 35714
>   };
>
> +/*
> + * From the datasheet:
> + * Value	| Sensor input field range (Ga)	| Gain (counts/milli-Gauss)
> + * 0		| (+-)0.7			| 1620
> + * 1		| (+-)1.0			| 1300
> + * 2		| (+-)1.5			| 970
> + * 3		| (+-)2.0			| 780
> + * 4		| (+-)3.2			| 530
> + * 5		| (+-)3.8			| 460
> + * 6		| (+-)4.5			| 390
> + * 7		| (+-)6.5			| 280
> + */
>   static const int regval_to_input_field_mg[] = {
>   	700,
>   	1000,
> @@ -113,6 +125,19 @@ static const int regval_to_input_field_mg[] = {
>   	4500,
>   	6500
>   };
> +
> +/*
> + * From the datasheet:
> + * Value	| Data output rate (Hz)
> + * 0		| 0.5
> + * 1		| 1
> + * 2		| 2
> + * 3		| 5
> + * 4		| 10 (default)
> + * 5		| 20
> + * 6		| 50
> + * 7		| Not used
> + */
>   static const char * const regval_to_samp_freq[] = {
>   	"0.5",
>   	"1",
> @@ -130,18 +155,16 @@ static const unsigned short normal_i2c[] = { HMC5843_I2C_ADDRESS,
>   /* Each client has this additional data */
>   struct hmc5843_data {
>   	struct mutex lock;
I'd argue for doing it the other way round and realigning lock rather 
than removing the tabs, but that's just personal taste.
> -	u8		rate;
> -	u8		meas_conf;
> -	u8		operating_mode;
> -	u8		range;
> +	u8 rate;
> +	u8 meas_conf;
> +	u8 operating_mode;
> +	u8 range;
>   };
>
> -static void hmc5843_init_client(struct i2c_client *client);
> -
> +/* The lower two bits contain the current conversion mode */
Would prefer this as a kerneldoc description. But this is better than 
nothing!
>   static s32 hmc5843_configure(struct i2c_client *client,
>   				       u8 operating_mode)
>   {
> -	/* The lower two bits contain the current conversion mode */
>   	return i2c_smbus_write_byte_data(client,
>   					HMC5843_MODE_REG,
>   					operating_mode&  HMC5843_MODE_MASK);
> @@ -166,23 +189,22 @@ static int hmc5843_read_measurement(struct iio_dev *indio_dev,
>   	if (result<  0)
>   		return -EINVAL;
>
> -	*val	= (s16)swab16((u16)result);
> +	*val = (s16)swab16((u16)result);
>   	return IIO_VAL_INT;
>   }
>
> -
>   /*
> - * From the datasheet
> + * From the datasheet:
>    * 0 - Continuous-Conversion Mode: In continuous-conversion mode, the
> - * device continuously performs conversions and places the result in the
> - * data register.
> + *     device continuously performs conversions and places the result in
> + *     the data register.
>    *
> - * 1 - Single-Conversion Mode : device performs a single measurement,
> - *  sets RDY high and returned to sleep mode
> + * 1 - Single-Conversion Mode : Device performs a single measurement,
> + *     sets RDY high and returns to sleep mode.
>    *
> - * 2 - Idle Mode :  Device is placed in idle mode.
> + * 2 - Idle Mode : Device is placed in idle mode.
>    *
> - * 3 - Sleep Mode. Device is placed in sleep mode.
> + * 3 - Sleep Mode : Device is placed in sleep mode.
>    *
>    */
>   static ssize_t hmc5843_show_operating_mode(struct device *dev,
> @@ -206,13 +228,14 @@ static ssize_t hmc5843_set_operating_mode(struct device *dev,
>   	unsigned long operating_mode = 0;
>   	s32 status;
>   	int error;
> +
>   	mutex_lock(&data->lock);
>   	error = kstrtoul(buf, 10,&operating_mode);
>   	if (error) {
>   		count = error;
>   		goto exit;
>   	}
> -	dev_dbg(dev, "set Conversion mode to %lu\n", operating_mode);
> +	dev_dbg(dev, "set conversion mode to %lu\n", operating_mode);
>   	if (operating_mode>  HMC5843_MODE_SLEEP) {
>   		count = -EINVAL;
>   		goto exit;
> @@ -230,6 +253,7 @@ exit:
>   	mutex_unlock(&data->lock);
>   	return count;
>   }
> +
>   static IIO_DEVICE_ATTR(operating_mode,
>   			S_IWUSR | S_IRUGO,
>   			hmc5843_show_operating_mode,
> @@ -239,17 +263,19 @@ static IIO_DEVICE_ATTR(operating_mode,
>   /*
>    * API for setting the measurement configuration to
>    * Normal, Positive bias and Negative bias
> - * From the datasheet
>    *
> - * Normal measurement configuration (default): In normal measurement
> - * configuration the device follows normal measurement flow. Pins BP and BN
> - * are left floating and high impedance.
> + * From the datasheet:
> + * 0 - Normal measurement configuration (default): In normal measurement
> + *     configuration the device follows normal measurement flow. Pins BP
> + *     and BN are left floating and high impedance.
>    *
> - * Positive bias configuration: In positive bias configuration, a positive
> - * current is forced across the resistive load on pins BP and BN.
> + * 1 - Positive bias configuration: In positive bias configuration, a
> + *     positive current is forced across the resistive load on pins BP
> + *     and BN.
>    *
> - * Negative bias configuration. In negative bias configuration, a negative
> - * current is forced across the resistive load on pins BP and BN.
> + * 2 - Negative bias configuration. In negative bias configuration, a
> + *     negative current is forced across the resistive load on pins BP
> + *     and BN.
>    *
>    */
>   static s32 hmc5843_set_meas_conf(struct i2c_client *client,
> @@ -290,8 +316,7 @@ static ssize_t hmc5843_set_measurement_configuration(struct device *dev,
>   		return -EINVAL;
>
>   	mutex_lock(&data->lock);
> -
> -	dev_dbg(dev, "set mode to %lu\n", meas_conf);
> +	dev_dbg(dev, "set measurement configuration to %lu\n", meas_conf);
>   	if (hmc5843_set_meas_conf(client, meas_conf)) {
>   		count = -EINVAL;
>   		goto exit;
> @@ -302,25 +327,13 @@ exit:
>   	mutex_unlock(&data->lock);
>   	return count;
>   }
> +
>   static IIO_DEVICE_ATTR(meas_conf,
>   			S_IWUSR | S_IRUGO,
>   			hmc5843_show_measurement_configuration,
>   			hmc5843_set_measurement_configuration,
>   			0);
>
> -/*
> - * From Datasheet
> - * The table shows the minimum data output
> - * Value	| Minimum data output rate(Hz)
> - * 0		| 0.5
> - * 1		| 1
> - * 2		| 2
> - * 3		| 5
> - * 4		| 10 (default)
> - * 5		| 20
> - * 6		| 50
> - * 7		| Not used
> - */
>   static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("0.5 1 2 5 10 20 50");
>
>   static s32 hmc5843_set_rate(struct i2c_client *client,
> @@ -333,7 +346,7 @@ static s32 hmc5843_set_rate(struct i2c_client *client,
>   	reg_val = (data->meas_conf) |  (rate<<  HMC5843_RATE_OFFSET);
>   	if (rate>= HMC5843_RATE_NOT_USED) {
>   		dev_err(&client->dev,
> -			"This data output rate is not supported\n");
> +			"data output rate is not supported\n");
>   		return -EINVAL;
>   	}
>   	return i2c_smbus_write_byte_data(client, HMC5843_CONFIG_REG_A, reg_val);
> @@ -392,31 +405,19 @@ static ssize_t show_sampling_frequency(struct device *dev,
>   	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
>   	s32 rate;
>
> -	rate = i2c_smbus_read_byte_data(client,  this_attr->address);
> +	rate = i2c_smbus_read_byte_data(client, this_attr->address);
>   	if (rate<  0)
>   		return rate;
>   	rate = (rate&  HMC5843_RATE_BITMASK)>>  HMC5843_RATE_OFFSET;
>   	return sprintf(buf, "%s\n", regval_to_samp_freq[rate]);
>   }
> +
>   static IIO_DEVICE_ATTR(sampling_frequency,
>   			S_IWUSR | S_IRUGO,
>   			show_sampling_frequency,
>   			set_sampling_frequency,
>   			HMC5843_CONFIG_REG_A);
>
> -/*
> - * From Datasheet
> - *	Nominal gain settings
> - * Value	| Sensor Input Field Range(Ga)	| Gain(counts/ milli-gauss)
> - *0		|(+-)0.7			|1620
> - *1		|(+-)1.0			|1300
> - *2		|(+-)1.5			|970
> - *3		|(+-)2.0			|780
> - *4		|(+-)3.2			|530
> - *5		|(+-)3.8			|460
> - *6		|(+-)4.5			|390
> - *7		|(+-)6.5			|280
> - */
>   static ssize_t show_range(struct device *dev,
>   				struct device_attribute *attr,
>   				char *buf)
> @@ -440,6 +441,7 @@ static ssize_t set_range(struct device *dev,
>   	struct hmc5843_data *data = iio_priv(indio_dev);
>   	unsigned long range = 0;
>   	int error;
> +
>   	mutex_lock(&data->lock);
>   	error = kstrtoul(buf, 10,&range);
>   	if (error) {
> @@ -461,8 +463,8 @@ static ssize_t set_range(struct device *dev,
>   exit:
>   	mutex_unlock(&data->lock);
>   	return count;
> -
>   }
> +
>   static IIO_DEVICE_ATTR(in_magn_range,
>   			S_IWUSR | S_IRUGO,
>   			show_range,
> @@ -537,7 +539,7 @@ static int hmc5843_detect(struct i2c_client *client,
>   	return 0;
>   }
>
> -/* Called when we have found a new HMC5843. */
> +/* Called when we have found a new HMC5843 */
>   static void hmc5843_init_client(struct i2c_client *client)
>   {
>   	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> @@ -548,6 +550,7 @@ static void hmc5843_init_client(struct i2c_client *client)
>   	hmc5843_configure(client, data->operating_mode);
>   	i2c_smbus_write_byte_data(client, HMC5843_CONFIG_REG_B, data->range);
>   	mutex_init(&data->lock);
> +
>   	pr_info("HMC5843 initialized\n");
>   }
>
> @@ -577,8 +580,6 @@ static int hmc5843_probe(struct i2c_client *client,
>   	data->operating_mode = HMC5843_MODE_CONVERSION_CONTINUOUS;
>
>   	i2c_set_clientdata(client, indio_dev);
> -
> -	/* Initialize the HMC5843 chip */
>   	hmc5843_init_client(client);
>
>   	indio_dev->info =&hmc5843_info;
> @@ -587,10 +588,13 @@ static int hmc5843_probe(struct i2c_client *client,
>   	indio_dev->num_channels = ARRAY_SIZE(hmc5843_channels);
>   	indio_dev->dev.parent =&client->dev;
>   	indio_dev->modes = INDIO_DIRECT_MODE;
> +
>   	err = iio_device_register(indio_dev);
>   	if (err)
>   		goto exit_free2;
> +
>   	return 0;
> +
>   exit_free2:
>   	iio_device_free(indio_dev);
>   exit: