Re: [PATCH V3 3/5] iio: accel: sca3300: modified to support multi chips

[Melin Tomas <tomas.melin@vaisala.com>]

Hi,

Some comments below.

On 04/05/2022 16:36, LI Qingwu wrote:
> The drive support sca3300 only.
> There are some other similar chips, for instance, SCL3300.
> Prepare the way for multiple chips and additional channels.
> Modify the driver to read the device id.
> Add the tables for the corresponding id to support multiple chips.
> Add prepares for the addition of extra channels.
> Add prepares for handling the operation modes for multiple chips.
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Reviewed-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: LI Qingwu <Qing-wu.Li@leica-geosystems.com.cn>
> ---
>  drivers/iio/accel/sca3300.c | 180 ++++++++++++++++++++++++++++--------
>  1 file changed, 141 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/iio/accel/sca3300.c b/drivers/iio/accel/sca3300.c
> index ff16d2cc8c70..1e0e6a2f7a63 100644
> --- a/drivers/iio/accel/sca3300.c
> +++ b/drivers/iio/accel/sca3300.c
> @@ -37,7 +37,6 @@
>  
>  /* Device ID */
>  #define SCA3300_REG_WHOAMI	0x10
> -#define SCA3300_WHOAMI_ID	0x51
I suggest leaving this here, define another value for scl3000 if needed.
>  
>  /* Device return status and mask */
>  #define SCA3300_VALUE_RS_ERROR	0x3
> @@ -93,15 +92,35 @@ static const struct iio_chan_spec sca3300_channels[] = {
>  	IIO_CHAN_SOFT_TIMESTAMP(4),
>  };
>  
> -static const int sca3300_lp_freq[] = {70, 70, 70, 10};
> -static const int sca3300_accel_scale[][2] = {{0, 370}, {0, 741}, {0, 185}, {0, 185}};
> +static const int sca3300_freq_tbl[] = {70, 10};
> +static const int sca3300_freq_modes_map[] = {0, 0, 0, 1};
>  
> +static const int sca3300_accel_scale_tbl[][2] = {{0, 370}, {0, 741}, {0, 185}};
> +static const int sca3300_accel_scale_modes_map[] = {0, 1, 2, 2};
Suggest keeping name of this intact, and keep name of the map variable
similar.
static const int sca3300_accel_scale[][2] = {{0, 370}, {0, 741}, {0, 185}};
static const int sca3300_accel_scale_map[] = {0, 1, 2, 2};

That keeps it easy to remember that these are related to each other.

> +
> +static const int sca3300_avail_modes_map[] = {0, 1, 2, 3};
>  static const unsigned long sca3300_scan_masks[] = {
>  	BIT(SCA3300_ACC_X) | BIT(SCA3300_ACC_Y) | BIT(SCA3300_ACC_Z) |
>  	BIT(SCA3300_TEMP),
>  	0
>  };
>  
> +struct sca3300_chip_info {
> +	const struct iio_chan_spec *channels;
> +	const int (*accel_scale_table)[2];> +	const int *accel_scale_modes_map;
> +	const unsigned long *scan_masks;
> +	const int *avail_modes_table;
> +	const int *freq_modes_map;
> +	const int *freq_table;> +	const u8 num_accel_scales;
> +	const u8 num_avail_modes;
> +	const u8 num_channels;
> +	const u8 num_freqs;
> +	const u8 chip_id;
> +	const char *name;
Suggest keeping related variables logically sorted in declaration
together instead of sorting according to length.
> +};
> +
>  /**
>   * struct sca3300_data - device data
>   * @spi: SPI device structure
> @@ -117,10 +136,28 @@ struct sca3300_data {
>  		s16 channels[4];
>  		s64 ts __aligned(sizeof(s64));
>  	} scan;
> +	const struct sca3300_chip_info *chip;
>  	u8 txbuf[4] ____cacheline_aligned;
>  	u8 rxbuf[4];
>  };
>  
> +static const struct sca3300_chip_info sca3300_chip_tbl[] = {
> +	{	.num_accel_scales = ARRAY_SIZE(sca3300_accel_scale_tbl)*2,> +		.accel_scale_modes_map = sca3300_accel_scale_modes_map,
> +		.accel_scale_table = sca3300_accel_scale_tbl,
> +		.num_channels = ARRAY_SIZE(sca3300_channels),
> +		.freq_modes_map = sca3300_freq_modes_map,
> +		.avail_modes_table = sca3300_avail_modes_map,
> +		.freq_table = sca3300_freq_tbl,
> +		.scan_masks = sca3300_scan_masks,
> +		.channels = sca3300_channels,
> +		.num_avail_modes = 4,
> +		.name = "sca3300",
> +		.chip_id = 0x51,
> +		.num_freqs = 2,
> +	},
> +};
> +
>  DECLARE_CRC8_TABLE(sca3300_crc_table);
>  
>  static int sca3300_transfer(struct sca3300_data *sca_data, int *val)
> @@ -227,36 +264,80 @@ static int sca3300_write_reg(struct sca3300_data *sca_data, u8 reg, int val)
>  	return sca3300_error_handler(sca_data);
>  }
>  
> +static int sca3300_set_op_mode(struct sca3300_data *sca_data, int index)
> +{
> +	int mode;
> +
> +	if ((index < 0) || (index >= sca_data->chip->num_avail_modes))
> +		return -EINVAL;
> +
> +	mode = sca_data->chip->avail_modes_table[index];
> +
> +	return sca3300_write_reg(sca_data, SCA3300_REG_MODE, mode);
> +}
> +
> +static int sca3300_get_op_mode(struct sca3300_data *sca_data, int *index)
> +{
> +	int reg_val;
> +	int ret;
> +	int i;
> +
> +	ret = sca3300_read_reg(sca_data, SCA3300_REG_MODE, &reg_val);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < sca_data->chip->num_avail_modes; i++) {
> +		if (sca_data->chip->avail_modes_table[i] == reg_val) {
> +			*index = i;
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
>  static int sca3300_write_raw(struct iio_dev *indio_dev,
>  			     struct iio_chan_spec const *chan,
>  			     int val, int val2, long mask)
>  {
>  	struct sca3300_data *data = iio_priv(indio_dev);
> +	int mode = -1;
Suggest not setting to invalid default value, instead avoid calling
function if values are not found.

>  	int reg_val;
> +	int index;
>  	int ret;
>  	int i;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_SCALE:
> -		if (val)
> +		if (chan->type != IIO_ACCEL)
>  			return -EINVAL;
Was there some problem with if (val) here, or why changed?
> -
> -		for (i = 0; i < ARRAY_SIZE(sca3300_accel_scale); i++) {
> -			if (val2 == sca3300_accel_scale[i][1])
> -				return sca3300_write_reg(data, SCA3300_REG_MODE, i);
> +		for (i = 0; i < data->chip->num_avail_modes; i++) { 4
> +			index = data->chip->accel_scale_modes_map[i];
> +			if ((val == data->chip->accel_scale_table[index][0]) &&
> +			(val2 == data->chip->accel_scale_table[index][1])) {
> +				mode = i;
> +				break;
> +			}
>  		}
> -		return -EINVAL;
> -
> +		return sca3300_set_op_mode(data, mode);
>  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> -		ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
> +		ret = sca3300_get_op_mode(data, &reg_val);
>  		if (ret)
>  			return ret;
> -		/* freq. change is possible only for mode 3 and 4 */
> -		if (reg_val == 2 && val == sca3300_lp_freq[3])
> -			return sca3300_write_reg(data, SCA3300_REG_MODE, 3);
> -		if (reg_val == 3 && val == sca3300_lp_freq[2])
> -			return sca3300_write_reg(data, SCA3300_REG_MODE, 2);
> -		return -EINVAL;
> +		index = data->chip->accel_scale_modes_map[reg_val];
> +		for (i = 0; i < data->chip->num_avail_modes; i++) {
> +			int index_new = data->chip->accel_scale_modes_map[i]; 0122
> +			int index_freq = data->chip->freq_modes_map[i];
Declare variables at top of function.
> +
> +			if (val == data->chip->freq_table[index_freq]) {
> +				if (data->chip->accel_scale_table[index] ==
> +				data->chip->accel_scale_table[index_new]) {
To be compatible with existing code, this should check that mode is 2 or
3. I don't see how this does that, please explain.

> +					mode = i;
> +					break;
> +				}
> +			}
> +		}
> +		return sca3300_set_op_mode(data, mode);
>  	default:
>  		return -EINVAL;
>  	}
> @@ -267,8 +348,9 @@ static int sca3300_read_raw(struct iio_dev *indio_dev,
>  			    int *val, int *val2, long mask)
>  {
>  	struct sca3300_data *data = iio_priv(indio_dev);
> -	int ret;
>  	int reg_val;
> +	int index;
> +	int ret;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> @@ -277,17 +359,25 @@ static int sca3300_read_raw(struct iio_dev *indio_dev,
>  			return ret;
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
> -		ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
> +		ret = sca3300_get_op_mode(data, &reg_val);
>  		if (ret)
>  			return ret;
> -		*val = 0;
> -		*val2 = sca3300_accel_scale[reg_val][1];
> -		return IIO_VAL_INT_PLUS_MICRO;
> +		switch (chan->type) {
> +		case IIO_ACCEL:
> +			index = data->chip->accel_scale_modes_map[reg_val];
> +			*val = data->chip->accel_scale_table[index][0];
> +			*val2 = data->chip->accel_scale_table[index][1];
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		default:
> +			return -EINVAL;
> +		}
>  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> -		ret = sca3300_read_reg(data, SCA3300_REG_MODE, &reg_val);
> +
> +		ret = sca3300_get_op_mode(data, &reg_val);
>  		if (ret)
>  			return ret;
> -		*val = sca3300_lp_freq[reg_val];
> +		index = data->chip->freq_modes_map[reg_val];
> +		*val = data->chip->freq_table[index];
>  		return IIO_VAL_INT;
>  	default:
>  		return -EINVAL;
> @@ -331,6 +421,7 @@ static int sca3300_init(struct sca3300_data *sca_data,
>  {
>  	int value = 0;
>  	int ret;
> +	int i;
>  
>  	ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE,
>  				SCA3300_MODE_SW_RESET);
> @@ -347,12 +438,22 @@ static int sca3300_init(struct sca3300_data *sca_data,
>  	if (ret)
>  		return ret;
>  
> -	if (value != SCA3300_WHOAMI_ID) {
> -		dev_err(&sca_data->spi->dev,
> -			"device id not expected value, %d != %u\n",
> -			value, SCA3300_WHOAMI_ID);
> +	for (i = 0; i < ARRAY_SIZE(sca3300_chip_tbl); i++) {
> +		if (sca3300_chip_tbl[i].chip_id == value)
> +			break;
> +	}> +	if (i == ARRAY_SIZE(sca3300_chip_tbl)) {
> +		dev_err(&sca_data->spi->dev, "Invalid chip %x\n", value);
Please start this with small letter, also perhaps resort to "unknown
chip id %x\n" or so.
>  		return -ENODEV;
>  	}
> +
> +	indio_dev->available_scan_masks = sca3300_chip_tbl[i].scan_masks;
> +	indio_dev->num_channels = sca3300_chip_tbl[i].num_channels;
> +	indio_dev->channels = sca3300_chip_tbl[i].channels;
> +	sca_data->chip = &sca3300_chip_tbl[i];
> +	indio_dev->name = sca3300_chip_tbl[i].name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
I would prefer to keep the above indio_dev additions in the probe
function. That way we keep the init function clean(er).

Thanks,
Tomas

>  	return 0;
>  }
>  
> @@ -384,15 +485,21 @@ static int sca3300_read_avail(struct iio_dev *indio_dev,
>  			      const int **vals, int *type, int *length,
>  			      long mask)
>  {
> +	struct sca3300_data *data = iio_priv(indio_dev);
>  	switch (mask) {
>  	case IIO_CHAN_INFO_SCALE:
> -		*vals = (const int *)sca3300_accel_scale;
> -		*length = ARRAY_SIZE(sca3300_accel_scale) * 2 - 2;
> -		*type = IIO_VAL_INT_PLUS_MICRO;
> -		return IIO_AVAIL_LIST;
> +		switch (chan->type) {
> +		case IIO_ACCEL:
> +			*vals = (const int *)data->chip->accel_scale_table;
> +			*length = data->chip->num_accel_scales;
> +			*type = IIO_VAL_INT_PLUS_MICRO;
> +			return IIO_AVAIL_LIST;
> +		default:
> +			return -EINVAL;
> +		}
>  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> -		*vals = &sca3300_lp_freq[2];
> -		*length = 2;
> +		*vals = (const int *)data->chip->freq_table;
> +		*length = data->chip->num_freqs;
>  		*type = IIO_VAL_INT;
>  		return IIO_AVAIL_LIST;
>  	default:
> @@ -424,11 +531,6 @@ static int sca3300_probe(struct spi_device *spi)
>  	crc8_populate_msb(sca3300_crc_table, SCA3300_CRC8_POLYNOMIAL);
>  
>  	indio_dev->info = &sca3300_info;
> -	indio_dev->name = SCA3300_ALIAS;
> -	indio_dev->modes = INDIO_DIRECT_MODE;
> -	indio_dev->channels = sca3300_channels;
> -	indio_dev->num_channels = ARRAY_SIZE(sca3300_channels);
> -	indio_dev->available_scan_masks = sca3300_scan_masks;
>  
>  	ret = sca3300_init(sca_data, indio_dev);
>  	if (ret) {