[PATCH 7/8] eeepc-laptop: document fan_pwm conversions

From: Frans Klaver
Date: Wed Oct 22 2014 - 15:13:34 EST


eeepc_get_fan_pwm and eeepc_set_fan_pwm convert the PWM value read from
the fan to a range lmsensors understands. Unfortunately this is only
clear if you are familiar with how lmsensors handles duty cycles.

Introduce two conversion functions that document the goal of these
conversions.

Signed-off-by: Frans Klaver <fransklaver@xxxxxxxxx>
---
drivers/platform/x86/eeepc-laptop.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
index f820bb3..275a239 100644
--- a/drivers/platform/x86/eeepc-laptop.c
+++ b/drivers/platform/x86/eeepc-laptop.c
@@ -974,18 +974,28 @@ static struct platform_driver platform_driver = {
#define EEEPC_EC_SFB0 0xD0
#define EEEPC_EC_FAN_CTRL (EEEPC_EC_SFB0 + 3) /* Byte containing SF25 */

+static inline int eeepc_pwm_to_lmsensors(int value)
+{
+ return value * 255 / 100;
+}
+
+static inline int eeepc_lmsensors_to_pwm(int value)
+{
+ value = clamp_val(value, 0, 255);
+ return value * 100 / 255;
+}
+
static int eeepc_get_fan_pwm(void)
{
u8 value = 0;

ec_read(EEEPC_EC_FAN_PWM, &value);
- return value * 255 / 100;
+ return eeepc_pwm_to_lmsensors(value);
}

static void eeepc_set_fan_pwm(int value)
{
- value = clamp_val(value, 0, 255);
- value = value * 100 / 255;
+ value = eeepc_lmsensors_to_pwm(value);
ec_write(EEEPC_EC_FAN_PWM, value);
}

--
2.1.0

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