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Message-ID: <4b05448b65969f9f433f7ac3aa234c33025ad262.1732811829.git.mazziesaccount@gmail.com>
Date: Thu, 28 Nov 2024 18:51:00 +0200
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Matti Vaittinen <mazziesaccount@...il.com>,
Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc: Matti Vaittinen <mazziesaccount@...il.com>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] iio: gts: simplify scale table build
The GTS helpers offer two different set of "available scales" -tables.
Drivers can choose to advertice the scales which are available on a
currently selected integration time (by just changing the hwgain).
Another option is to list all scales which can be supported using any of
the integration times. This is useful for drivers which allow scale
setting to also change the integration time to meet the scale user
prefers.
The helper function which build these tables for the GTS did firstbuild
the "time specific" scale arrays for all the times. This is done by
calculating the scales based on the integration time specific "total
gain" arrays (gain contributed by both the integration time and hw-gain).
After this the helper code calculates an array for all available scales.
This is done combining all the time specific total-gains into one sorted
array, removing dublicate gains and finally converting the gains to
scales as above.
This can be somewhat simplified by changing the logic for calculating
the 'all available scales' -array to directly use the time specific
scale arrays instead of time specific total-gain arrays. Code can
directly just add all the already computed time specific scales to one
big 'all scales'-array, keep it sorted and remove duplicates.
Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
---
This has been tested by IIO-gts kunit tests only. All testing is
appreciated.
Comparing the scales is not as pretty as comparing the gains was, as
scales are in two ints where the gains were in one. This makes the code
slightly more hairy. I however believe that the logic is now more
obvious. This might be more important for one reading this later...
---
drivers/iio/industrialio-gts-helper.c | 109 ++++++++++----------------
1 file changed, 42 insertions(+), 67 deletions(-)
diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c
index 7f900f578f1d..31101848b194 100644
--- a/drivers/iio/industrialio-gts-helper.c
+++ b/drivers/iio/industrialio-gts-helper.c
@@ -191,86 +191,61 @@ static int fill_and_sort_scaletables(struct iio_gts *gts, int **gains, int **sca
return 0;
}
-static int combine_gain_tables(struct iio_gts *gts, int **gains,
- int *all_gains, size_t gain_bytes)
+static int scale_eq(int *sc1, int *sc2)
{
- int i, new_idx, time_idx;
+ return *sc1 == *sc2 && *(sc1 + 1) == *(sc2 + 1);
+}
- /*
- * We assume all the gains for same integration time were unique.
- * It is likely the first time table had greatest time multiplier as
- * the times are in the order of preference and greater times are
- * usually preferred. Hence we start from the last table which is likely
- * to have the smallest total gains.
- */
- time_idx = gts->num_itime - 1;
- memcpy(all_gains, gains[time_idx], gain_bytes);
- new_idx = gts->num_hwgain;
+static int scale_smaller(int *sc1, int *sc2)
+{
+ if (*sc1 != *sc2)
+ return *sc1 < *sc2;
+
+ /* If integer parts are equal, fixp parts */
+ return *(sc1 + 1) < *(sc2 + 1);
+}
+
+static int do_combined_scaletable(struct iio_gts *gts, int **scales, size_t scale_bytes)
+{
+ int t_idx, i, new_idx;
+ int *all_scales = kcalloc(gts->num_itime, scale_bytes, GFP_KERNEL);
- while (time_idx-- > 0) {
- for (i = 0; i < gts->num_hwgain; i++) {
- int candidate = gains[time_idx][i];
+ if (!all_scales)
+ return -ENOMEM;
+
+ t_idx = gts->num_itime - 1;
+ memcpy(all_scales, scales[t_idx], scale_bytes);
+ new_idx = gts->num_hwgain * 2;
+
+ while (t_idx-- > 0) {
+ for (i = 0; i < gts->num_hwgain ; i++) {
+ int *candidate = &scales[t_idx][i * 2];
int chk;
- if (candidate > all_gains[new_idx - 1]) {
- all_gains[new_idx] = candidate;
- new_idx++;
+ if (scale_smaller(candidate, &all_scales[new_idx - 2])) {
+ all_scales[new_idx] = *candidate;
+ all_scales[new_idx + 1] = *(candidate + 1);
+ new_idx += 2;
continue;
}
- for (chk = 0; chk < new_idx; chk++)
- if (candidate <= all_gains[chk])
+ for (chk = 0; chk < new_idx; chk += 2)
+ if (!scale_smaller(candidate, &all_scales[chk]))
break;
- if (candidate == all_gains[chk])
+
+ if (scale_eq(candidate, &all_scales[chk]))
continue;
- memmove(&all_gains[chk + 1], &all_gains[chk],
+ memmove(&all_scales[chk + 2], &all_scales[chk],
(new_idx - chk) * sizeof(int));
- all_gains[chk] = candidate;
- new_idx++;
+ all_scales[chk] = *candidate;
+ all_scales[chk + 1] = *(candidate + 1);
+ new_idx += 2;
}
}
- return new_idx;
-}
-
-static int *build_all_scales_table(struct iio_gts *gts, int *all_gains, int num_scales)
-{
- int i, ret;
- int *all_scales __free(kfree) = kcalloc(num_scales, 2 * sizeof(int),
- GFP_KERNEL);
-
- if (!all_scales)
- return ERR_PTR(-ENOMEM);
-
- for (i = 0; i < num_scales; i++) {
- ret = iio_gts_total_gain_to_scale(gts, all_gains[i], &all_scales[i * 2],
- &all_scales[i * 2 + 1]);
- if (ret)
- return ERR_PTR(ret);
- }
-
- return_ptr(all_scales);
-}
-
-static int build_combined_tables(struct iio_gts *gts,
- int **gains, size_t gain_bytes)
-{
- int *all_scales, num_gains;
- int *all_gains __free(kfree) = kcalloc(gts->num_itime, gain_bytes,
- GFP_KERNEL);
-
- if (!all_gains)
- return -ENOMEM;
-
- num_gains = combine_gain_tables(gts, gains, all_gains, gain_bytes);
-
- all_scales = build_all_scales_table(gts, all_gains, num_gains);
- if (IS_ERR(all_scales))
- return PTR_ERR(all_scales);
-
- gts->num_avail_all_scales = num_gains;
+ gts->num_avail_all_scales = new_idx / 2;
gts->avail_all_scales_table = all_scales;
return 0;
@@ -279,15 +254,15 @@ static int build_combined_tables(struct iio_gts *gts,
static int gain_to_scaletables(struct iio_gts *gts, int **gains, int **scales)
{
int ret;
- size_t gain_bytes;
+ size_t scale_bytes;
ret = fill_and_sort_scaletables(gts, gains, scales);
if (ret)
return ret;
- gain_bytes = array_size(gts->num_hwgain, sizeof(int));
+ scale_bytes = array_size(gts->num_hwgain, 2 * sizeof(int));
- return build_combined_tables(gts, gains, gain_bytes);
+ return do_combined_scaletable(gts, scales, scale_bytes);
}
/**
--
2.47.0
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