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thermal: broadcom: Use clamp to simplify bcm2835_thermal_temp2adc

PATCH RESEND Applied Thorsten Blum 4 participants 4 messages Jan 5 – Jan 21

Subsystems (3)
Broadcom BCM2711/BCM2835 Arm architecture Thermal Broadcom BCM281XX/BCM11XXX/BCM216XX Arm architecture
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Thorsten Blum

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#0 lore raw

PATCH RESEND 1/1 thermal: broadcom: Use clamp to simplify bcm2835_thermal_temp2adc

Use clamp() to simplify bcm2835_thermal_temp2adc() and improve its readability. Explicitly cast BIT() to int to prevent a signedness error.

Signed-off-by Thorsten Blum <[email protected]>
---
 drivers/thermal/broadcom/bcm2835_thermal.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)
drivers/thermal/broadcom/bcm2835_thermal.c +2 -6
index 685a5aee5e0d..c5105dfc6ec9 100644
@@ -11,6 +11,7 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>

@@ -80,12 +81,7 @@ static int bcm2835_thermal_temp2adc(int temp, int offset, int slope)
 	temp -= offset;
 	temp /= slope;
 
-	if (temp < 0)
-		temp = 0;
-	if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
-		temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
-
-	return temp;
+	return clamp(temp, 0, (int)BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1);
 }
 
 static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
#2 lore raw
In reply to Thorsten Blum
Quoted 21 lines · On Mon, 5 Jan 2026 13:13:03 +0100 Thorsten Blum <[email protected]>…

Use clamp() to simplify bcm2835_thermal_temp2adc() and improve its readability. Explicitly cast BIT() to int to prevent a signedness error.

Signed-off-by Thorsten Blum <[email protected]>
---
 drivers/thermal/broadcom/bcm2835_thermal.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)
drivers/thermal/broadcom/bcm2835_thermal.c +1 -0
index 685a5aee5e0d..c5105dfc6ec9 100644
@@ -11,6 +11,7 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>

drivers/thermal/broadcom/bcm2835_thermal.c static int bcm2835_thermal_temp2adc(int temp, int offset, int slope) · line 84

Quoted 10 lines
drivers/thermal/broadcom/bcm2835_thermal.c +1 -6
@@ -80,12 +81,7 @@ static int bcm2835_thermal_temp2adc(int temp, int offset, int slope)
 	temp -= offset;
 	temp /= slope;
 
-	if (temp < 0)
-		temp = 0;
-	if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
-		temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
-
-	return temp;
+	return clamp(temp, 0, (int)BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1);

Hmmm....
I wonder if I can get 'statically_true(lo >= 0)' into the type check so that cast isn't necessary.
signed_val < 0 ? 0 : signed_val > unsigned_val ? unsigned_val : signed_val
is fine.
Would mean swapping the order of the tests - which shouldn't break anything. But will need a full audit - various bits of code have relied on the order of the comparisons.

David

Quoted 4 lines
drivers/thermal/broadcom/bcm2835_thermal.c +0 -0
 }
 
 static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
Applied
#3 lore raw
In reply to Thorsten Blum

drivers/thermal/broadcom/bcm2835_thermal.c

Quoted 11 lines · Thorsten Blum

Use clamp() to simplify bcm2835_thermal_temp2adc() and improve its readability. Explicitly cast BIT() to int to prevent a signedness error.

Signed-off-by Thorsten Blum <[email protected]>
---
  drivers/thermal/broadcom/bcm2835_thermal.c | 8 ++------
  1 file changed, 2 insertions(+), 6 deletions(-)
drivers/thermal/broadcom/bcm2835_thermal.c +0 -1
index 685a5aee5e0d..c5105dfc6ec9 100644
--- a/drivers/thermal/broadcom/bcm2835_thermal.c

Applied, thanks

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