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* [PATCH] iio: light: tsl2591: reduce code duplication in tsl2591_persist_* functions
@ 2026-04-18 18:54 LucasRabaquim
  2026-04-18 21:21 ` David Lechner
  0 siblings, 1 reply; 2+ messages in thread
From: LucasRabaquim @ 2026-04-18 18:54 UTC (permalink / raw)
  To: jic23, dlechner, nuno.sa, andy; +Cc: LucasRabaquim, Matheus Feitosa, linux-iio

Add tsl2591_persist_table as a bidirectional lookup table for
tsl2591_persist_cycle_to_lit and tsl2591_persist_lit_to_cycle functions

These functions were prone to errors in the case of adding or updating
TSL2591_PRST_ALS_INT_CYCLE_* values. The functions utilize a for-loop
like in the function tsl2591_als_time_to_fval, allowing it to compare
the cycle value with tsl2591_persist_table[i].cycle and return lit
value with tsl2591_persist_table[i].lit as defined in the new type
tsl2591_persist_entry, reducing the risk of logic mismatches.

Signed-off-by: LucasRabaquim <lucas.rabaquim@usp.br>
Co-developed-by: Matheus Feitosa <matheus.feitosa@usp.br>
Signed-off-by: Matheus Feitosa <matheus.feitosa@usp.br>
---
 drivers/iio/light/tsl2591.c | 104 +++++++++++++-----------------------
 1 file changed, 38 insertions(+), 66 deletions(-)

diff --git a/drivers/iio/light/tsl2591.c b/drivers/iio/light/tsl2591.c
index c5557867ea43..86483f0b2e01 100644
--- a/drivers/iio/light/tsl2591.c
+++ b/drivers/iio/light/tsl2591.c
@@ -170,6 +170,12 @@ struct tsl2591_chip {
 	bool events_enabled;
 };
 
+/* Persist cycle conversion table mapping register cycles to lit values */
+struct tsl2591_persist_entry {
+	u8 cycle;
+	int lit;
+};
+
 /*
  * Period table is ALS persist cycle x integration time setting
  * Integration times: 100ms, 200ms, 300ms, 400ms, 500ms, 600ms
@@ -229,80 +235,46 @@ static int tsl2591_multiplier_to_gain(const u32 multiplier)
 	}
 }
 
+static const struct tsl2591_persist_entry 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 (als_persist == tsl2591_persist_table[i].cycle)
+			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 (als_persist == tsl2591_persist_table[i].lit)
+			return tsl2591_persist_table[i].cycle;
 	}
+
+	return -EINVAL;
 }
 
 static int tsl2591_compatible_int_time(struct tsl2591_chip *chip,
-- 
2.47.3


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2026-04-18 18:54 [PATCH] iio: light: tsl2591: reduce code duplication in tsl2591_persist_* functions LucasRabaquim
2026-04-18 21:21 ` David Lechner

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