Re: [PATCH v4 3/6] iio: imu: adis: Add DIAG_STAT register size

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 10 Jan 2025 09:42:51 +0200
Robert Budai <robert.budai@analog.com> wrote:

> Some devices may have more than 16 bits of status. This patch allows the
> user to specify the size of the DIAG_STAT register. It defaults to 2 if
> not specified. This is mainly for backward compatibility.
> 
> Co-developed-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
> Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
> Co-developed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> Signed-off-by: Robert Budai <robert.budai@analog.com>
> ---
>  drivers/iio/imu/adis.c       | 11 ++++++++---
>  include/linux/iio/imu/adis.h |  2 ++
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
> index 9e4113473dc4..a072307bfb6a 100644
> --- a/drivers/iio/imu/adis.c
> +++ b/drivers/iio/imu/adis.c
> @@ -304,11 +304,15 @@ EXPORT_SYMBOL_NS(__adis_enable_irq, "IIO_ADISLIB");
>   */
>  int __adis_check_status(struct adis *adis)
>  {
> -	u16 status;
> +	unsigned int status;
>  	int ret;
>  	int i;
>  
> -	ret = __adis_read_reg_16(adis, adis->data->diag_stat_reg, &status);
> +	if (adis->data->diag_stat_size)
> +		ret = adis->ops->read(adis, adis->data->diag_stat_reg, &status,
> +				      adis->data->diag_stat_size);
> +	else
> +		ret = __adis_read_reg_16(adis, adis->data->diag_stat_reg, (u16 *)&status);
>  	if (ret)
>  		return ret;
>  
> @@ -317,7 +321,8 @@ int __adis_check_status(struct adis *adis)
>  	if (status == 0)
>  		return 0;
>  
> -	for (i = 0; i < 16; ++i) {
> +	for (i = 0; i < BITS_PER_BYTE * ((adis->data->diag_stat_size) ?
> +					 adis->data->diag_stat_size : 2); ++i) {

This is getting hard to read.  I think a local variable is appropriate.

>  		if (status & BIT(i)) {
>  			dev_err(&adis->spi->dev, "%s.\n",
>  				adis->data->status_error_msgs[i]);
> diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
> index 52652f51db2e..b888b22f5c8c 100644
> --- a/include/linux/iio/imu/adis.h
> +++ b/include/linux/iio/imu/adis.h
> @@ -44,6 +44,7 @@ struct adis_timeout {
>   * @glob_cmd_reg: Register address of the GLOB_CMD register
>   * @msc_ctrl_reg: Register address of the MSC_CTRL register
>   * @diag_stat_reg: Register address of the DIAG_STAT register
> + * @diag_stat_size: Length (in bytes) of the DIAG_STAT register.

Add something about 0 being treated as meaning 2. Or add this to
all instances of this structure so we don't need that 0 case.
Whilst there are quite a lot instances, they are mostly filled
by a couple of macros so it shouldn't be too bad to update them all.

>   * @prod_id_reg: Register address of the PROD_ID register
>   * @prod_id: Product ID code that should be expected when reading @prod_id_reg
>   * @self_test_mask: Bitmask of supported self-test operations
> @@ -70,6 +71,7 @@ struct adis_data {
>  	unsigned int glob_cmd_reg;
>  	unsigned int msc_ctrl_reg;
>  	unsigned int diag_stat_reg;
> +	unsigned int diag_stat_size;
>  	unsigned int prod_id_reg;
>  
>  	unsigned int prod_id;