Re: [PATCH v4 3/5] iio: amplifiers: hmc425a: move conversion logic

Jonathan Cameron
2024-01-21T17:08:14Z

On Wed, 17 Jan 2024 14:51:12 +0200
Dumitru Ceclan <mitrutzceclan@gmail.com> wrote:

> Move gain-dB<->code conversion logic from read_raw and write_raw to
> hmc425a_gain_dB_to_code() and hmc425a_code_to_gain_dB().
>
> Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
Some comments inline

Jonathan

> ---
> drivers/iio/amplifiers/hmc425a.c | 102 ++++++++++++++++++-------------
> 1 file changed, 59 insertions(+), 43 deletions(-)
>
> diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc425a.c
> index ed4d72922696..e1162a500daf 100644
> --- a/drivers/iio/amplifiers/hmc425a.c
> +++ b/drivers/iio/amplifiers/hmc425a.c
> @@ -56,35 +56,72 @@ static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
> return 0;
> }
>
> +static int hmc425a_gain_dB_to_code(struct hmc425a_state *st, int val, int val2, int *code)
> +{
> + struct hmc425a_chip_info *inf = st->chip_info;
> + int gain, temp;
> +
> + if (val < 0)
> + gain = (val * 1000) - (val2 / 1000);
> + else
> + gain = (val * 1000) + (val2 / 1000);
> +
> + if (gain > inf->gain_max || gain < inf->gain_min)
> + return -EINVAL;
> +
> + switch (st->type) {
> + case ID_HMC425A:
> + *code = ~((abs(gain) / 500) & 0x3F);

In the next patch I point out that this should be data or callbacks in in
the st->chip_info structure, not encoded in code here based on st->type (which
I want you to get rid of!)

> + return 0;
> + case ID_HMC540S:
> + *code = ~((abs(gain) / 1000) & 0xF);
> + return 0;
> + case ID_ADRF5740:
> + temp = (abs(gain) / 2000) & 0xF;
> + *code = temp & BIT(3) ? temp | BIT(2) : temp;

Given you are moving the code, a comment here might be nice as it's unusual
(bits are 2DB, 4DB, 8DB and another 8DB)

> + return 0;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int hmc425a_code_to_gain_dB(struct hmc425a_state *st, int *val, int *val2)
> +{
> + int code, gain;
> +
> + code = st->gain;
> + switch (st->type) {
> + case ID_HMC425A:
> + gain = ~code * -500;
> + break;
> + case ID_HMC540S:
> + gain = ~code * -1000;
> + break;
> + case ID_ADRF5740:
> + code = code & BIT(3) ? code & ~BIT(2) : code;
> + gain = code * -2000;
> + break;
> + }
> +
> + *val = gain / 1000;
> + *val2 = (gain % 1000) * 1000;
> +
> + return 0;
> +}
> +
> static int hmc425a_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan, int *val,
> int *val2, long m)
> {
> struct hmc425a_state *st = iio_priv(indio_dev);
> - int code, gain = 0;
> int ret;
>
> mutex_lock(&st->lock);
> switch (m) {
> case IIO_CHAN_INFO_HARDWAREGAIN:
> - code = st->gain;
> -
> - switch (st->type) {
> - case ID_HMC425A:
> - gain = ~code * -500;
> - break;
> - case ID_HMC540S:
> - gain = ~code * -1000;
> + ret = hmc425a_code_to_gain_dB(st, val, val2);
> + if (ret)
> break;
> - case ID_ADRF5740:
> - code = code & BIT(3) ? code & ~BIT(2) : code;
> - gain = code * -2000;
> - break;
> - }
> -
> - *val = gain / 1000;
> - *val2 = (gain % 1000) * 1000;
> -
> ret = IIO_VAL_INT_PLUS_MICRO_DB;
> break;
> default:
> @@ -100,36 +137,15 @@ static int hmc425a_write_raw(struct iio_dev *indio_dev,
> int val2, long mask)
> {
> struct hmc425a_state *st = iio_priv(indio_dev);
> - struct hmc425a_chip_info *inf = st->chip_info;
> - int code = 0, gain;
> - int ret;
> -
> - if (val < 0)
> - gain = (val * 1000) - (val2 / 1000);
> - else
> - gain = (val * 1000) + (val2 / 1000);
> -
> - if (gain > inf->gain_max || gain < inf->gain_min)
> - return -EINVAL;
> -
> - switch (st->type) {
> - case ID_HMC425A:
> - code = ~((abs(gain) / 500) & 0x3F);
> - break;
> - case ID_HMC540S:
> - code = ~((abs(gain) / 1000) & 0xF);
> - break;
> - case ID_ADRF5740:
> - code = (abs(gain) / 2000) & 0xF;
> - code = code & BIT(3) ? code | BIT(2) : code;
> - break;
> - }
> + int code = 0, ret;
>
> mutex_lock(&st->lock);
> switch (mask) {
> case IIO_CHAN_INFO_HARDWAREGAIN:
> + ret = hmc425a_gain_dB_to_code(st, val, val2, &code);
> + if (ret)
> + break;
> st->gain = code;
> -
> ret = hmc425a_write(indio_dev, st->gain);
> break;