[PATCH] iio: light: tsl2591: replace persist switch statements with lookup table

[PATCH] iio: light: tsl2591: replace persist switch statements with lookup table

[Caio]

tsl2591_persist_cycle_to_lit() and tsl2591_persist_lit_to_cycle() are
inverse mappings of the same 15-entry table, duplicating the same
pairs across two switch statements. Replace both with a shared
tsl2591_persist_table[] array and simple linear searches, eliminating
the duplication.

Signed-off-by: Caio <caio.groff@usp.br>
---
 drivers/iio/light/tsl2591.c | 104 ++++++++++++------------------------
 1 file changed, 35 insertions(+), 69 deletions(-)

diff --git a/drivers/iio/light/tsl2591.c b/drivers/iio/light/tsl2591.c
index c5557867e..6626e6d0b 100644
--- a/drivers/iio/light/tsl2591.c
+++ b/drivers/iio/light/tsl2591.c
@@ -229,80 +229,46 @@ static int tsl2591_multiplier_to_gain(const u32 multiplier)
 	}
 }
 
+struct tsl2591_persist_map {
+	u8 cycle;
+	int lit;
+};
+
+static const struct tsl2591_persist_map tsl2591_persist_table[] = {
+	{ TSL2591_PRST_ALS_INT_CYCLE_ANY, 1  },
+	{ TSL2591_PRST_ALS_INT_CYCLE_2,   2  },
+	{ TSL2591_PRST_ALS_INT_CYCLE_3,   3  },
+	{ TSL2591_PRST_ALS_INT_CYCLE_5,   5  },
+	{ TSL2591_PRST_ALS_INT_CYCLE_10,  10 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_15,  15 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_20,  20 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_25,  25 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_30,  30 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_35,  35 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_40,  40 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_45,  45 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_50,  50 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_55,  55 },
+	{ TSL2591_PRST_ALS_INT_CYCLE_60,  60 },
+};
+
 static int tsl2591_persist_cycle_to_lit(const u8 als_persist)
 {
-	switch (als_persist) {
-	case TSL2591_PRST_ALS_INT_CYCLE_ANY:
-		return 1;
-	case TSL2591_PRST_ALS_INT_CYCLE_2:
-		return 2;
-	case TSL2591_PRST_ALS_INT_CYCLE_3:
-		return 3;
-	case TSL2591_PRST_ALS_INT_CYCLE_5:
-		return 5;
-	case TSL2591_PRST_ALS_INT_CYCLE_10:
-		return 10;
-	case TSL2591_PRST_ALS_INT_CYCLE_15:
-		return 15;
-	case TSL2591_PRST_ALS_INT_CYCLE_20:
-		return 20;
-	case TSL2591_PRST_ALS_INT_CYCLE_25:
-		return 25;
-	case TSL2591_PRST_ALS_INT_CYCLE_30:
-		return 30;
-	case TSL2591_PRST_ALS_INT_CYCLE_35:
-		return 35;
-	case TSL2591_PRST_ALS_INT_CYCLE_40:
-		return 40;
-	case TSL2591_PRST_ALS_INT_CYCLE_45:
-		return 45;
-	case TSL2591_PRST_ALS_INT_CYCLE_50:
-		return 50;
-	case TSL2591_PRST_ALS_INT_CYCLE_55:
-		return 55;
-	case TSL2591_PRST_ALS_INT_CYCLE_60:
-		return 60;
-	default:
-		return -EINVAL;
-	}
-}
+	int i;
 
+	for (i = 0; i < ARRAY_SIZE(tsl2591_persist_table); i++)
+		if (tsl2591_persist_table[i].cycle == als_persist)
+			return tsl2591_persist_table[i].lit;
+	return -EINVAL;
+}
 static int tsl2591_persist_lit_to_cycle(const u8 als_persist)
 {
-	switch (als_persist) {
-	case 1:
-		return TSL2591_PRST_ALS_INT_CYCLE_ANY;
-	case 2:
-		return TSL2591_PRST_ALS_INT_CYCLE_2;
-	case 3:
-		return TSL2591_PRST_ALS_INT_CYCLE_3;
-	case 5:
-		return TSL2591_PRST_ALS_INT_CYCLE_5;
-	case 10:
-		return TSL2591_PRST_ALS_INT_CYCLE_10;
-	case 15:
-		return TSL2591_PRST_ALS_INT_CYCLE_15;
-	case 20:
-		return TSL2591_PRST_ALS_INT_CYCLE_20;
-	case 25:
-		return TSL2591_PRST_ALS_INT_CYCLE_25;
-	case 30:
-		return TSL2591_PRST_ALS_INT_CYCLE_30;
-	case 35:
-		return TSL2591_PRST_ALS_INT_CYCLE_35;
-	case 40:
-		return TSL2591_PRST_ALS_INT_CYCLE_40;
-	case 45:
-		return TSL2591_PRST_ALS_INT_CYCLE_45;
-	case 50:
-		return TSL2591_PRST_ALS_INT_CYCLE_50;
-	case 55:
-		return TSL2591_PRST_ALS_INT_CYCLE_55;
-	case 60:
-		return TSL2591_PRST_ALS_INT_CYCLE_60;
-	default:
-		return -EINVAL;
-	}
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(tsl2591_persist_table); i++)
+		if (tsl2591_persist_table[i].lit == als_persist)
+			return tsl2591_persist_table[i].cycle;
+	return -EINVAL;
 }
 
 static int tsl2591_compatible_int_time(struct tsl2591_chip *chip,
-- 
2.34.1

Re: [PATCH] iio: light: tsl2591: replace persist switch statements with lookup table

[David Lechner]

On 6/17/26 11:42 AM, Caio wrote:
> tsl2591_persist_cycle_to_lit() and tsl2591_persist_lit_to_cycle() are
> inverse mappings of the same 15-entry table, duplicating the same
> pairs across two switch statements. Replace both with a shared
> tsl2591_persist_table[] array and simple linear searches, eliminating
> the duplication.
> 
Isn't this the same thing as [1]?

https://lore.kernel.org/linux-iio/20260522182058.199762-1-matheus.feitosa@usp.br/

Re: [PATCH] iio: light: tsl2591: replace persist switch statements with lookup table

[Joshua Crofts]

On Wed, 17 Jun 2026 13:42:58 -0300
Caio <caio.groff@usp.br> wrote:

> tsl2591_persist_cycle_to_lit() and tsl2591_persist_lit_to_cycle() are
> inverse mappings of the same 15-entry table, duplicating the same
> pairs across two switch statements. Replace both with a shared
> tsl2591_persist_table[] array and simple linear searches, eliminating
> the duplication.
> 
> Signed-off-by: Caio <caio.groff@usp.br>
> ---

Alongside David's comment, you're missing your full name in the
Signed-off-by tag.

-- 
Kind regards

CJD

Re: [PATCH] iio: light: tsl2591: replace persist switch statements with lookup table

[Andy Shevchenko]

On Wed, Jun 17, 2026 at 01:42:58PM -0300, Caio wrote:
> tsl2591_persist_cycle_to_lit() and tsl2591_persist_lit_to_cycle() are
> inverse mappings of the same 15-entry table, duplicating the same
> pairs across two switch statements. Replace both with a shared
> tsl2591_persist_table[] array and simple linear searches, eliminating
> the duplication.

I have a déjà vu about this...
https://lore.kernel.org/linux-iio/20260528185912.24774-1-matheus.feitosa@usp.br/
Ah, and this what was applied already. please, base your code on the respective
tree and branch.

-- 
With Best Regards,
Andy Shevchenko